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Grade 8 science las

The document provides a learning activity sheet on force and motion for 8th grade science students. It includes activities that investigate the relationship between force, mass, and acceleration through examples of forces acting on objects like footballs, pendulums, boxes, and carts. Students are asked to analyze diagrams, apply Newton's laws of motion, and determine the net force, acceleration, and changes in motion of various objects based on the applied and contact forces.

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8 SCIENCE FIRST QUARTER LEARNING ACTIVITY SHEET
i Learning Activity Sheet in SCIENCE (Grade 8) Copyright © 2020 DEPARTMENT OF EDUCATION Regional Office No. 02 (Cagayan Valley) Regional Government Center, Carig Sur, Tuguegarao City, 3500 “No copy of this material shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit.” This material has been developed for the implementation of K to 12 Curriculum through the Curriculum and Learning Management Division (CLMD). It can be reproduced for educational purposes and the source must be acknowledged. Derivatives of the work including creating an edited version, an enhancement of supplementary work are permitted provided all original works are acknowledged and the copyright is attributed. No work may be derived from this material for commercial purposes and profit. Republic of the Philippines Department of Education COPYRIGHT PAGE _____________________________________________ Address: Regional Government Center, Carig Sur, Tuguegarao City, 3500 Telephone Nos.: (078) 304-3855; (078) 396-9728 Email Address: region2@deped.gov.ph Website: region2.deped.gov.ph Consultants: Regional Director : ESTELA L. CARIÑO, EdD., CESO IV Assistant Regional Director : RHODA T. RAZON, EdD., CESO V Schools Division Superintendent : REYNANTE Z. CALIGUIRAN, PhD Asst. Schools Division Superintendent : JESUS B. MAGGAY Chief Education Supervisor, CLMD : OCTAVIO V. CABASAG, PhD Chief Education Supervisor, CID : ESTELA S. CABARO, PhD Development Team Writers : ERIC B. PASION, MARIA LORESA J. TUMANGUIL, RIZZA C. BALORAN, SHEELA A. APOSTOL, EDGAR A. SADDUL, GEMMA U. PACAMALAN, REOWIN PALATTAO, VENIE DE LEON, KAREN GACUTAN, MAPHILINDO TURARAY, EDUARDO C. DELA ROSA, DIANA D. LACAMBRA, VICTORIA T. IRINGAN, Cagayan Nat’l HS, Tuguegarao City Science HS Content Editor: EDUARDO C. DELA ROSA, Cagayan National High School ULYSSES DAQUIAOG, Ugad National HS, SDO Isabela Language Editor : MYRNA Q. ADDURU, VISITACION LIGUTAN Illustrators : KATHERINE D. MELAD, TRISHA ELIZABETH J. TUMANGUIL, EMERLITA N. MORALES, VENIE DE LEON Layout Artists : ERIC B. PASION, Cagayan National High School Focal Persons : MYRNA Q. ADDURU, PhD, EPS Science SDO Tuguegarao City JESSICA T. CASTANEDA, PhD, EPS LRMS, SDO Tuguegarao City ESTER T. GRAMAJE, EPS Science-CLMD, DepEd RO2 RIZALINO G. CARONAN, EPS LRMS, DepEd R02 Printed by: DepEd Regional Office No. 02
ii Table of Contents Competency Page number Investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion ..................... 1 Infer that when a body exerts a force on another, an equal amount of force is exerted back on it ..................... 20 Identify and explain the factors that affect potential and kinetic energy ..................... 33 Investigates the effect of temperature to the speed of sound ..................... 45 Explain the hierarchy of colors in relation to the energy of visible light ..................... 57 Differentiate between heat and temperature at the molecular level ..................... 68 Infer the relationship between current and voltage ..................... 78 Explain the advantages and disadvantages of series and parallel connections in homes ..................... 100 Explain the functions of circuit breakers, fuses, earthing, double insulation, and other safety devices in the home ..................... 112
1 SCIENCE 8 Name of Learner: ______________________________ Grade Level: _________________ Section: ______________________________________ Date: _______________________ LEARNING ACTIVITY SHEET Force and Motion Background Information for the Learners: In your Grade 7, you described the motion of objects in terms of distance, displacement, speed, velocity, and acceleration. As you remember, distance is the total length of path travelled. Displacement on the other hand is the shortest distance the object makes with respect to the reference point. In other words, distance is measured by virtue of the object’s path, while displacement is measured by virtue of the object’s final position with the point of reference. The time rate at which an object changes distance is speed. Speed tells us how fast the object is going. When the speed of the object is zero, it means that the object is at rest. When the speed of an object has a magnitude equal to any number, it means that the object is moving. The time rate of change in displacement is velocity. Velocity describes how fast the object changes position with respect to the reference point. Zero velocity may mean two things. It may be that the object is at rest or it is moving but is located just right where the reference point is at that instant of time! Just like when you are running around the oval or making a U-turn and returned to the spot where you started. Objects do not usually travel in uniform speed or uniform velocity. This means, velocity changes over time. Objects usually speed up or slow down. Acceleration tells how fast an object changes its velocity. When the acceleration of the object is zero, it means that the object is in equilibrium condition or a state of balance. In other words, the object may not be moving (static equilibrium), or the object is moving at constant velocity (dynamic equilibrium). When this equilibrium condition is disturbed, the object’s state motion is also disrupted. An object that is initially at rest may now begin to move. Similarly, an object that is initially moving at constant speed or constant velocity may speed up, may slow down, or may change direction. In other words, the object accelerates. What causes these changes in an object’s motion and how does it affect acceleration? These are the things that we will investigate through this learning activity sheets.
2 Learning Competency with Code: Investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion. (Quarter 1, Week 1, S8FE-Ia-15) Activity 1. Loop-a-Word Directions: There are 15 words related to motion which are hidden in the box below. Locate and encircle them. M E R N N I W J F W G N E W T O N Q U E A I F O R C E K H E M S C K H V D W A R G R O S D G I C U I N T E A C T I O N J N A P K F S G M T G U A M L Z X C E G B I F U J N U T Y N H V S Y Q F K M S V T T M L R D X H Q I T W J N M U L A L O E U C L S I Z U K I X K V A I Z J S D X N D G P Y W O G H V T E Q W W A Y S H N S E F B N O R M A L G G U R T S D G P Q I H V K V G C C R B B W F K M B I M T W O I E M G E K U I L I B R O U M R N X V N R C R S W K F S X U V P L X V E N P O I Q T I N E R T I A N G S L M W C P A J F B O P M J Y R L E H K J E N I T L H H R M R E H L A I Z T A L H O L J I Y H E I T Q F X T P D G R K Q S B X L O G M D C Y W A C C E L E R A T I O N P N E D F T R N M J Z Q D S N Z J F R S C B F I A I L I N E O F A C T I O N D W O C Z U Z O T C U W H V D Y J X Q I B P U S H S J N
3 Force is any __ __ __ __ __ __ __ __ __ __ __ that causes change in an object’s motion. It is caused by either __ __ __ __ or__ __ __ __. Force is a vector quantity with three characteristics. These are line of action, __ __ __ __ __ __ __ __ __, and __ __ __ __ __ __ __ __ __. The SI unit of force is the __ __ __ __ __ __. It is denoted in symbol by capital letter __. It is defined as the amount of force that causes a one-kilogram mass object an acceleration of one meter per second squared in the direction of the force. The expanded form of this unit is __ __ ▪ __ / __ 2 . Activity 2. What can Force Do? Directions: Have you experienced playing football or have you ever watched a football game? Study the picture below and answer the questions that follow. 1. In a football game, what is exerted on the ball as the player kicks it? _____________________________________________________________________ 2. If the football is initially at rest, what happens to its speed as the player kicks it? _____________________________________________________________________ 3. While the football is rolling on the ground, does the surface of the ground offer an opposite force on the ball? _______________________________________________ 4. What is this force exerted by the ground surface on the ball? _____________________________________________________________________ 5. What is the effect of this force to the football’s speed? _____________________________________________________________________ 6. How about when another player blocks a flying football. Does the player exert a force on the ball? ___________________________________________________________ 7. What is the effect of this blocking force to the football’s speed? _____________________________________________________________________ 8. What is the effect of this force to the football’s direction of travel? _____________________________________________________________________ Activity 3. Complete the Message Directions: Fill in the spaces to complete all the statements inside the box. Each space corresponds to a letter.
4 Activity 4. Balanced Force Normally, there are more than one forces acting on an object. When two or more forces act on an object, they add up algebraically to get the combined effect of the forces called Resultant Force or Net Force. Directions: A free-body diagram (FBD) illustrates the forces acting on an object to determine the resultant force. Interpret the free-body diagrams below and answer the questions that follow. A. Tension A pendulum is suspended at a certain height. The string exerts tension on the bob with a force of 0.01 N. The weight of the bob is also 0.01 N. String Tension = 0.01 N Pendulum bob Weight = 0.01 N 1. What are the two forces acting on the bob? __________________________________ 2. What is the direction of each force? ________________________________________ 3. Using the Cartesian coordinate plane (x-y coordinate plane) what is the sign of an upward force? _________________________________________________________ 4. Using the Cartesian coordinate plane (x-y coordinate plane) what is the sign of a downward force? ______________________________________________________ 5. With positive and negative signs affixed with the upward and downward forces, respectively, add the two forces together. F net = F1 + F2 _________________________________________________________________________________________ 6. If the Fnet on the pendulum is equal to zero, will the bob swing sideways? __________ 7. If the Fnet on the pendulum is equal to zero, will the bob move upward? ___________ 8. If the Fnet on the pendulum is equal to zero, will the bob move downward? _________ 9. Are the two forces acting on the pendulum balanced? __________________________ 10. What is the Fnet when forces are balanced? __________________________________
5 B. Normal A box weighing 20 N is placed on top of a table. The table supports the weight of the box with an upward normal force of 20 N. Box Normal = 20 N Table Weight = 20 N 1. What are the two forces acting on the box? __________________________________ 2. What is the direction of each force? ________________________________________ 3. Which force takes a positive sign? _________________________________________ 4. Which force takes a negative sign? ________________________________________ 5. With positive and negative signs affixed with the upward and downward forces, respectively, add the two forces together. F net = F1 + F2 ___________________________________________________________________ 6. If the Fnet is equal to zero, will the box slide sideways? ________________________ 7. Are the two forces acting on the box balanced? ______________________________ 8. What makes the forces balanced? Describe their magnitude and direction. _____________________________________________________________________ _________________________________________________________________ C. Friction A load is pushed to the right along a horizontal floor with a force of 50 N. Static friction acts towards the opposite direction with a frictional force of 50 N. Load Static Friction = 50 N F1= 50 N Floor 1. What is the net force or resultant force, Fnet? ___________________________ 2. Are the two forces acting on the load balanced? ________________________ 3. Will the box move because of balanced forces? ________________________ Balanced forces on objects that are initially at rest illustrate the first fragment of Newton’s First Law of Motion or the Law of Inertia. Complete the statement of the Law of Inertia for objects that are initially at rest. Write the correct group of words on the blank.. When forces are balanced, objects at rest will _________________.
6 Activity5. Unbalanced Force Directions: Read and analyze the given situations and the free-body diagrams below. Answer the questions that follow. A. A load initially at rest is pushed to the right along a horizontal floor with a force of 50 N. Starting friction acts towards the opposite direction with a frictional force of 20 N. Load Starting Friction = 20 N F1= 50 N Floor 1. What is the magnitude of the resultant force or Fnet? ___________________________ 2. What is the direction of the net force? ______________________________________ 3. Are the forces balanced? ________________________________________________ 4. Will the load move? ____________________________________________________ 5. In what direction will the load move? ______________________________________ B. A boy pushes a toy car at the back with a force of 2 N, to the right. Another boy applies a force of 3 N to the right by pulling a string attached in front of the toy. The sliding friction is 2 N to the left. Toy car F1 = 2 N Friction = 2N F2 = 3 N Floor 1. What is the magnitude of the resultant or net force? _____________________ 2. What is the direction of the resultant force? ____________________________ 3. Will the toy car move? In what direction will it go?______________________ _______________________________________________________________
7 Objects at rest will remain at rest. Objects in motion will continue to __ __ __ __ in a __ __ __ __ __ __ __ __ line path with a __ __ __ __ __ __ __ __ speed, unless acted upon by a net force or __ __ __ __ __ __ __ __ __ __ force. C. A ball rolling along a horizontal floor in a straight line path with a constant velocity of 2 m/s is kicked with a force of 5 N to the right. Rolling friction between the surfaces of the ball and the ground is 2.5 N Ball F1 = 5 N Floor Friction = 2N 1. What is the magnitude of the net, resultant force? _______________________ 2. What is the direction of the net, resultant force? ________________________ 3. What is the velocity of the ball before it was kicked? ____________________ 4. What is constant velocity? Does it speed up, slow down, or remain the same? _______________________________________________________________ 5. What is expected to happen to the speed of the ball after the kick? _______________________________________________________________ 6. What causes any change in the state of motion of the ball? _______________________________________________________________ Complete the statement of Newton’s First Law of Motion or the Law of Inertia.
8 Activity 6. Effect of Force to Acceleration Directions: Investigate how different amounts of force affect the object’s acceleration differently by examining the given situations below. Answer the questions that follow. A. Two wooden carts below having the same mass of 2 kilograms are lying on a frictionless horizontal floor. The first cart is pushed with a force of 2 N to the right, while the second cart is pushed with a force of 4 N to the right. Cart 1 Fnet = 2 N Frictionless Floor Cart 2 Fnet = 4 N Frictionless Floor 1. What is the effect of Fnet on both carts? _____________________________________ 2. Which of the two carts will gain greater velocity? _____________________________ 3. Which of the two carts will accelerate faster? ________________________________ 4. How many times faster will one cart accelerate compared to the other? ____________ 5. What happens to the acceleration of the cart when the force applied to it is doubled? _____________________________________________________________________ B. Another cart is now placed on the same floor. Cart 3 has the same mass of 2 kilograms with Cart 1 and Cart 2. A force of 8 N to the right is exerted to it. Compare the effect of this force with the first two carts. Answer the questions that follow. Cart 3 Fnet = 8 N Frictionless Floor 1. How much greater is the net force on cart 3 compared to cart 1? _________________ 2. How much faster will cart 3 accelerate, compared to cart 1? ____________________ 3. How much greater is the net force of cart 3 compared to cart 2? _________________ 4. How much faster will cart 3 accelerate, compared to cart 2? ____________________ 5. When net force is increased, what happens to the acceleration? __________________ 6. What is the relationship of net force and acceleration? _________________________ ____________________________________________________________________
9 Acceleration is (directly, inversely) proportional to net force. This means that increasing the net external force applied to an object will (decrease, increase) the object’s acceleration. When force is doubled, acceleration is (doubled, halved).When force is decreased four times, acceleration (increases four times, decreases four times). At this point you should be able to state the effect of net force to the acceleration of an object. This is the first fragment of the statement of Newton’s Second Law of Motion or the Law of Acceleration! Encircle the correct term enclosed in the parenthesis to complete each statement in the box below.
10 Activity 7. Effect of Mass to Acceleration Directions: Investigate the effect of mass to an object’s acceleration by examining the given situations below. Answer the questions that follow. A. Two wooden carts lying on a frictionless horizontal floor are pushed with equal amount of force of 10 N to the right. The first cart has a mass of 5 kg, while the second cart has a mass of 10 kg. Cart 1 mass = 5 kg Fnet = 10 N Frictionless Floor Cart 2 mass = 10 kg Fnet = 10 N Frictionless Floor 1. Which of the two carts will gain greater acceleration? _________________________ 2. How many times the acceleration of one cart as compared to the other cart be? _____________________________________________________________________ 3. What affects the difference in the acceleration of the two carts? __________________ 4. What happens to the acceleration of the cart when the mass is doubled? _____________________________________________________________________
11 Acceleration is (directly, inversely) proportional to mass. This means that increasing the mass of an object will (decrease, increase) the object’s acceleration. When mass is doubled, acceleration is (doubled, halved). When mass is decreased four times, acceleration (increases four times, decreases four times). B. Another cart is placed on the same floor as shown below. The same amount of force as Cart 1 and Cart 2 is applied to Cart 3. The mass of Cart 3 is 20 kilograms. Compare the effect of this mass to acceleration with the other carts. Answer the questions that follow. Cart 3 mass = 20 kg Fnet = 10 N Frictionless Floor 1. How much greater is the mass of cart 3 as compared to cart 1? __________________ 2. How much slower will cart 3 accelerate as compared to cart 1? _________________ 3. How much greater is the mass of cart 3 as compared to cart 2? __________________ 4. How much slower will cart 3 accelerate as compared to cart 2? _________________ 5. When the mass of the object is increased, what happens to its acceleration? _____________________________________________________________________ At this point you should be able to state the effect of mass to the acceleration of an object. This is the second fragment of the statement of Newton’s Second Law of Motion or the Law of Acceleration! Encircle the correct term enclosed in the parenthesis to complete each statement in the box below.
12 Activity 8. Applying Newton’s Second Law of Motion Newton’s second law of motion or the Law of Acceleration can be summarized by the equation: Where: is the acceleration of the object in m/s2 ; is the net external force in newtons (N) ; and, m is the mass of the object in kilograms (kg). Directions: Apply this formula in solving the following problems. Show your complete solution. 1. A 5 kg object is pushed along a frictionless floor with a force of 3 N. What is the acceleration of the object? 2. How much force is needed to cause a 2 kilogram object with an acceleration of 6 m/s2 ? 3. What is the mass of an object accelerated at 4 m/s2 by a force of 20 N? 4. A cart with a mass of 8 kilograms is pulled along a horizontal rough surface with a force of 56 N. The floor offers a rolling friction of 16 N on the wheels of the cart. What is the acceleration of the cart? Cart mass = 8 kg F1 = 56 N Rough Surface Rolling Friction = 16 N
13 Activity 9. Summing it Up! Directions: With activities 1 to 8, you were able to investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion. In other words you described the motion of an object in terms of the factors causing such change in motion. To help you generalize your lesson, answer briefly the questions that follow. 1. In terms of motion, what can net external force do to an object? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. How does net external force affect the object’s acceleration? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 3. How does the object’s mass affect its acceleration? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Reflection: 1. I learned that __________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. I enjoyed most on _______________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 3. I want to learn more on ____________________________________________________ ________________________________________________________________________ ________________________________________________________________________
14 References: Campo, Pia C., et. al. 2003..Science – Grade 8. Learner’s Module. Pasig City. Department of Education. - Cordero-Navaza, Delia & Bienvenido J. Valdes. 1996. You and the Natural World Series: Physics. Quezon City, Philippines. Phoenix Publishing House Inc., Padua, Alicia L., et.al. 2003. Practical and Explorational Physics, Modular Approach. Quezon City, Philippines. Vibal Publishing House, Inc., Salmorin, Lolita M. & Alberto V. Florido Jr. 2009. Science and Technology IV-Physics. Quezon City, Philippines. Abiva Publishing House Inc., Silverio, Angelina A. & Rosemarie S. Cabauatan. 2006. Exploring Life Through Science. Physics. Teachers Guide. Quezon City, Philippines. Phoenix Publishing House, Inc., Young & Freedman. 2004. Sear’s and Zemansky’s University Physics with Modern Physics.11th Edition. San Francisco, California, USA. Pearson Education Inc.,
15 Answer Key Activity 1. M E R N N I W J F W G N E W T O N Q U E A I F O R C E K H E M S C K H V D W A R G R O S D G I C U I N T E A C T I O N J N A P K F S G M T G U A M L Z X C E G B I F U J N U T Y N H V S Y Q F K M S V T T M L R D X H Q I T W J N M U L A L O E U C L S I Z U K I X K V A I Z J S D X N D G P Y W O G H V T E Q W W A Y S H N S E F B N O R M A L G G U R T S D G P Q I H V K V G C C R B B W F K M B I M T W O I E M G E K U I L I B R O U M R N X V N R C R S W K F S X U V P L X V E N P O I Q T I N E R T I A N G S L M W C P A J F B O P M J Y R L E H K J E N I T L H H R M R E H L A I Z T A L H O L J I Y H E I T Q F X T P D G R K Q S B X L O G M D C Y W A C C E L E R A T I O N P N E D F T R N M J Z Q D S N Z J F R S C B F I A I L I N E O F A C T I O N D W O C Z U Z O T C U W H V D Y J X Q I B P U S H S J N Activity 2. 1. Force 2. Speeds up or increases 3. Yes 4. Friction 5. It slows down the ball. 6. Yes 7. The ball may stop or bounce with a faster / slower speed (answers may vary) 8. The ball changes direction
16 Activity 3. Force is any INTERACTION that causes change in an object’s motion. It is caused by either PUSHor PULL Force is a vector quantity with three characteristics. These are line of action, MAGNITUDE and DIRECTION. The SI unit of force is the NEWTON. It is denoted in symbol by capital letter N. It is defined as the amount of force that causes a one-kilogram mass object an acceleration of one meter per second squared in the direction of the force. The expanded form of this unit is kg▪m/s2 . Activity 4. A. Tension 1. Weight and Tension 2. Upward for tension, downward for weight 3. Positive 4. Negative 5. F net = F1 + F2= 0 Newton 6. No 7. No 8. No 9. Yes 10. Fnet= 0 N B. Normal 1. Normal and Weight 2. Upward for normal, downward for weight 3. Normal 4. Weight 5. F net = F1 + F2= 0 N 6. No 7. Yes 8. Forces are balanced when their F net is zero. Two forces are balanced when they are equal in magnitude but opposite in direction (* Teacher must emphasize that the forces must act on the same object) C. Friction 1. Fnet = 0 2. Yes 3. No
17 Complete the statement below. When forces are balanced, objects at rest will remain at rest. Activity 5. A. 1. Fnet = 30 N 2. To the right 3. No 4. Yes 5. To the right B. 1. 3 N 2. To the right 3. Yes.To the right C. 1. 3 N 2. To the right 3. Constant 2 m/s 4. Velocity/ speed remains the same 5. The ball will gain speed 6. Unbalanced force or net force Objects at rest will remain at rest. Objects in motion will continue to MOVE in a STRAIGHT line path with a CONSTANT speed, unless acted upon by a net force or UNBALANCED force. Activity 6. A. 1. Net force causes both carts to move 2. Cart 2 3. Cart 2 4. Cart 2 will accelerate 2x greater than Cart 1 5. The acceleration of the cart also doubles.
18 B. 1. Force on cart 3 is 4x greater than that of cart 1? 2. 4x faster 3. 2x greater 4. 2x faster 5. Acceleration also increases 6. Direct relationship/ acceleration increases with force Encircle the correct term enclosed in the parenthesis to complete each statement in the tale below. Acceleration is (directly, inversely) proportional to net force. This means that increasing the net external force applied to an object will (decrease, increase) the object’s acceleration. When force is doubled, acceleration is (doubled, halved). When force is decreased four times, acceleration (increases four times, decreases four times). Activity 7. A. 1. Cart 1 2. Cart 1 will gain twice as great as the acceleration of Cart 2. 3. Mass 4. Acceleration is halved B. 1. 4x greater 2. 4x slower 3. 2x greater 4. 2x slower 5. Acceleration decreases Encircle the correct term enclosed in the parenthesis to complete each statement in the box below. Acceleration is (directly, inversely) proportional to mass. This means that increasing the mass an object will (decrease, increase) the object’s acceleration. When mass is doubled, acceleration is (doubled, halved). When mass is decreased four times, acceleration (increases four times, decreases four times).
19 Activity 8. 1. 0.6 m/s2 2. 12 N 3. 5 kg 4. 5m/s2 Activity 9 1. A net force causes an object to move, stop, slow down, speed up, and/or change direction. Net force causes acceleration. 2. Net external force directly affects the object’s acceleration. When Fnet is increased, acceleration increases. 3. Mass inversely affects acceleration. When mass is increased, acceleration decreases. Prepared by: ERIC B. PASION Cagayan National High School
20 SCIENCE 8 Name of Learner: ______________________ Grade Level:_______________ Section: ______________________________ Date:_____________________ LEARNING ACTIVITY SHEET Newton’s Third Law of Motion Background Information for the Learners: Read the selection below: What is the moral of the story? If you encountered a situation similar to helping a certain person, would you also extend your service without hesitation? Take note of what the comic strip is saying. Do you want to understand why this is happening? Scientifically, one’s action and its reaction is explained by the force around us. A force is always part of a mutual action that involves another force. Basically, force is a push or a pull. A mutual action is an interaction between one thing and another. Why do forces always occur in pairs? Newton’s third law of motion states that whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. Paramedic Mike Sibal was born ten weeks early and in need of a trustworthy doctor. His parents found Jose Rapatan, MD, a pediatrician who stayed with the baby for two nights after he came down with a life-threateningly high fever. Thirty years later and all grown up, Sibal, a paramedic, was called in to help at the site of a car wreck. The car was on fire with a man still stuck inside. After firefighters helped put out the flames and Jaws of Life opened the car, Sibal brought the injured man into an ambulance. He learned the rescued victim’s name was Jose Rapatan—the very same Jose Rapatan who’d saved his life as a baby.
21 Newton’s third law describes the relationship between two forces in an interaction which has the following properties: Identifying Action and Reaction When action A exerts force on B, the reaction is simply B exerts a force on A. Look at the examples in the following figures. REACTION Action: Tire pushes the road Reaction: The road pushes the tire REACTION ACTION C T I O N Action: The tower exerts a weight on the earth Reaction: The earth exerts a normal force to support the tower REACTION ACTION
22 DID YOU KNOW? Understanding how a helicopter gets its lifting force Competency (Code): Infer that when a body exerts a force on another, an equal amount of force is exerted back on it (S8FE-Ia-16) ACTIVITY 1. What’s Your Action and Reaction? Directions: Identify from the situation the ACTION and its corresponding REACTION. Write down the Action and the Reaction Forces on the space provided on the right side of each illustration. To identify a pair of action-reaction forces, first identify the interacting objects A and B, and if the action is A on B, the reaction is B on A. There is a simple recipe for treating action and reaction forces: First identify the interaction. Let’s say one object, A, interacts with another object, B. Second, the action and reaction forces are stated in the form: Action: Object A exerts a force on object B. Reaction: Object B exerts a force on object A. 1. A bird while flying pushes the air downwards with the help of its wings. The air pushes the bird upwards for lift.
23 2. A man is propelled upward and then down into the swimming pool as he jumps on the diving board. He exerts a downward force on the diving board and the diving board simultaneously exerts an equal force on the man but in the upward direction. 3. Walking is possible- as you walk, you exert a force against the floor (down and backward) and the floor exerts a force back (up and forward), causing you to move forward. 4. 5. A fireman has to hold on tightly to a fire hose. The hose will fly backwards as water shoots out from it. The swimmer pushes against the water while the water pushes back on the swimmer and pushes her forward.
24 Activity 2. The Direction of Your Reaction Directions. Consider the following figure. Draw a counterpart arrow that illustrates the direction of the reaction force. 1. Action: Head bumps ball. Reaction:____________ 6. Action: Hand pulls on flower Reaction:____________ 2. Action: Windshield hits bug Reaction:____________ 7. Action: Athlete pushes barbell upward Reaction:____________ 3. Action: Fist hits wall Reaction:____________ 8. Action: Compressed air pushes balloon surface upward Reaction:____________ 4 Action: Hand touches nose Reaction:____________ 9. Action: Air rushes down Reaction:____________ 5. Action: Bat hits ball Reaction:____________ 10. Action: Foot pushes down Reaction:____________
25 Activity 3. Puzzled with Forces Directions. Fill in the crossword puzzle with the words missing from the sentences below. Match the number of the sentence to the boxes placed across or down the grid. 1 2 3 4 5 6 7 8 9 10 Across 3. Force acting on one direction 4. A man shoots a rifle and the force of the shot results in recoil. The magnitude of the force on the rifle __________ the magnitude of force on the bullet. 9. The force that acts on an object to stop its motion 10. Reaction always go in the _______ direction of the action Down 1. The force that pull things toward Earth 2. A book exerts a force of 2N downwards, into a chair that exerts a force of 5N downwards to the floor it stands on. What is the force that the floor exerts upwards on the chair? 5. For every action there is an equal and opposite reaction 6. Force acting on the opposite direction 7. Forces always come in _____. 8. A push or a pull
26 Activity 4. Force of Choices Directions: Choose the answer from the given questions. Encircle the letter of the correct answer. 1. What could correctly complete the following statement? “A force interaction requires at least a(n)________________” A.Action force. B. Pair of force. C. Reaction force. D.Single force. 2. What wouldcorrectly fill the following statement? “Whenever one subject exerts a force on a second object, the second object exerts a force on the first that is__________” A.in the same direction and equal in magnitude at the same time. B. in the same direction and lesser in magnitude at the same time C. opposite in direction and equal in magnitude at the same time. D.opposite in direction and greater in magnitude at the same time 3. What object will provide a forward motion force to a motor scooter along a higway which is a reaction from the vehicle’s tires? A.Engine B. Fuel C. Road D. Steering Wheel 4. What is the direction of gravity against a person when he jumps from the ground? A.Downward B. Upward C. To the left D. To the right 5. What will happen if a net force acts on a horse while pulling a wagon? A.The horse-wagon system accelerates. B. The horse-wagon system does not move. C. The horse-wagon system is pulled backwards. D.The horse will accelerate but the wagon will be steady. 6. At a pizza shop, the cook throws the pizza dough in the air. On what factor will the amount of force that the cook exerts on the dough depend on? A.Brand label of the dough C. Mass of the dough B. Color of the dough D. Strength of the dough 7. While driving down the road, a firefly strikes the windshield of a bus and makes a quite obvious mess in front of the face of the driver. The firefly hit the bus and the bus hits the firefly. Which of the following statements is correct? A.The force of the firefly on the windshield is zero. B. The force of the firefly is lesser than the force of the bus. C. The force of the firefly is greater than the force of the bus. D.The force of the firefly and the bus have no difference in magnitude. 8. Which of the following situation best describes Newton’s Third Law of Motion? A. A rifle recoils when fired. B. Occurrence of high and low tides. C. A follow through is needed when a golfer hits the ball with a golf club. D. A chocolate vendor has to move with the bus as he jumps off the bus. 9. Trisha, who has a mass of 30 kg stands on platform. What is the magnitude of force called Normal Force does the platform exert on Trisha? A. 9.8 N C. 257.5 N B. 30.00 N D. 294.00 N
27 10. Two 100-N weights are attached to a scale called spring balance as shown. What is the reading on the scale? A. 0 N B. 50 N C. 150 N D.200 N Activity 5- Decode the Forces in Your Life Life is a matter of decoding the forces around us. If you push hard on the world, the world pushes hard on you. If you touch the world gently, the world would touch you gently in return. Since you have mastered what the Newton’s Third Law of Motion says, it is now time to apply it to real life situations. Directions: Decrypt the following cryptograms. The titles are the clues of the phrases that you need to crack. These phrases are quotes which exhibits life’s action-reaction forces. Enjoy decoding! 1. Gaps, stimulus and reactions
28 2. Spiritual Reaction of a person 3. Emotional forces 4. To accept or to surrender
29 5. Self-Realization Reflection: In the third law of motion, if there is an action, there will be a reaction. In real-life situations, good deeds can yield the same. Thus, be reminded of the golden rule: do unto others what you want others to do unto you (Arevalo, R., 2017) 1. I learned that _______________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ 2. I enjoyed most on ___________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ 3. I want to learn more on _______________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________
30 References: “Action = Reaction.” 8TH GRADE SCIENCE. Accessed June 3, 2020. https://clarkscience8.weebly.com/action--reaction.html. Arevalo, Ryan L. Diwa Senior High School Series . Makati City, Philippines: Diwa Learning Systems Inc, 2017 “Comic Strip Starters: MakeBeliefxComix.com.” Make Beliefs Comix, September 15, 2019. https://www.makebeliefscomix.com/original-comic-strip-starters/. Google Search. Google. Accessed June 3, 2020. https://www.google.com/search?q=action and reaction quotes life&tbm=isch&source=iu&ictx=1&fir=mOsjoI2- TQZ68M:,4rj3NU2i9_Ou3M,_&vet=1&usg=AI4_- kS_b0khIiQMlHNWktiVifEdKKFf_w&sa=X&ved=2ahUKEwju3428lt3pAhWpwos BHRVkB7EQ9QEwB3oECAoQIg#imgrc=mOsjoI2-TQZ68M: Hewitt, Paul G. Conceptual Physics. Boston: Pearson, 2015. Padua, Alicia L, and Ricardo M Crisostomo. Practical and Ecxplorational Physics Modular Approach. Edited by Lilia M Rabago. Vibal Publishing House, Inc., 2003 “Reaction Sayings and Quotes.” Reaction Sayings and Reaction Quotes | Wise Old Sayings. Accessed May 27, 2020. https://www.wiseoldsayings.com/reaction-quotes/. “The Law of Action-Reaction (Revisited).” The Physics Classroom. Accessed May 28, 2020. https://www.physicsclassroom.com/class/momentum/Lesson-2/The-Law-of-Action- Reaction-(Revisited). “TOP 25 ACTION AND REACTION QUOTES: A-Z Quotes.” A. Accessed June 3, 2020. https://www.azquotes.com/quotes/topics/action-and-reaction.html. “Welcome to Discovery Education's Puzzlemaker! Create Crossword Puzzles, Word Searches, Mazes, and Other Puzzles for Your Classroom Today!” Welcome to Discovery Education's Puzzlemaker! Create crossword puzzles, word searches, mazes, and other puzzles for your classroom today! Accessed June 3, 2020. http://puzzlemaker.discoveryeducation.com/. Answer Key: Activity 1 1. Action: A bird wings pushes the air downwards. Reaction: The air pushes the bird upwards for lift. 2. Action: The man exerts a downward force on the diving board. Reaction: The diving board simultaneously exerts an equal force on the man but in the upward direction. 3. Action: A person exerts a force against the floor (down and backward).
31 Reaction: The floor exerts a force back (up and forward), causing you to move forward. 4. Action: A fireman has to hold on tightly to a fire hose Reaction: The hose will fly backwards as water shoots out from it. 5. Action: The swimmer pushes against the water Reaction: The water pushes back on the swimmer and pushes him forward. Activity 2 1. Action: Head bumps ball. Reaction: Ball bumps head 6. Action: Hand pulls on flower Reaction: Flower pulls on hand 2. Action: Windshield hits bug Reaction: Bug hits windshield 7. Action: Athlete pushes barbell upward Reaction: Barbell pushes down 3. Action: Fist hits wall Reaction: Wall hits fist 8. Action: Compressed air pushes balloon surface outward Reaction Balloon surface pushes ________ compressed air inward ___ 4 Action: Finger touches nose Reaction: Nose touches finger 9 Action: Air rushes down Reaction: Balloon goes up 5. Action: Bat hits ball Reaction: Ball hits bat 10. Action: Foot pushes down Reaction: Floor pushes up
32 Activity 4 1. B 2. C 3. C 4. A 5. A 6. C 7. D 8. A 9. C 10. A Activity 5 1. Create gaps between stimulus and reaction and the gap will show you the path by Amit Ray 2. God’s reaction towards things is different from ours and He wishes that our reaction will line up with His by Sunday Adelaja 3. How you react emotionally is a choice in any situation. by Judith Orloff 4. Acceptance is an active response to a temporary situation; surrender is a passive reaction to a situation that you think will last forever by Oli Anderson 5. If a man realizes who he is, he will not react to the negative things surrounding him by Sunday Adelaja. Prepared by: RIZZA C. BALORAN MARIA LORESA J. TUMANGUIL Tuguegarao City Science High School Illustrator: TRISHA ELIZABETH J. TUMANGUIL
33 SCIENCE 8 Name of Learner: ______________________ Grade Level: _______________ Section: ______________________________ Date: _____________________ LEARNING ACTIVITY SHEET Potential Energy and Kinetic Energy Background Information for the Learners: Read the comic strips.
34 Credits: https://www.storyboardthat.com/(https://www.storyboardthat.com/portal/storyboards/sheela0202 88/class-storyboard/potential-and-kinetic-energy3) Learning Competency and Code: Identify and explain the factors that affect the Potential Energy and Kinetic Energy of the object. (S8FE-Id-22)
35 Potential energy= weight x height (P.E =w x h) Note: Since weight=mass x acceleration due to gravity, P.E can be written also as (P.E =m x g x h) The units used are: Energy =Joules, J Weight= Newtons, N Height= meters, m Mass= Kilograms, kg Acceleration due to gravity= (9.8 m/s2 ) Activity 1: How Potential am I? Directions: Study table A and table B below and analyze the different quantities given. Then, answer the questions that follow. Table A: PE of the object when the mass varies while the height remains the same Table B: PE of the object when the mass remains the same as height increases 1: In table A, what happens to the P.E of the object when mass increases but the height of the object remains the same? ___________________________________________________________________________ 2: In table B, what happens to the P.E of the object when height increases but the mass of the object remains the same? ___________________________________________________________________________ 3: What are the factors that affect the P.E of an object? ___________________________________________________________________________ Mass, kg Acceleration due to gravity, m/s2 Height, m P.E (P.E=mgh), J 1 9.8 2 19.6 2 9.8 2 39.2 3 9.8 2 58.8 Mass, kg Acceleration due to gravity, m/s2 Height, m P.E (P.E=mgh), J 2 9.8 1 19.6 2 9.8 2 39.2 2 9.8 3 58.8
36 4: How can mass/weight and height affect the P.E of an object? ___________________________________________________________________________ 5: What is the relationship of mass/weight and height to the P.E of an object? ___________________________________________________________________________ 6: Give at least two (2) situations where we can apply P.E in our real life. ___________________________________________________________________________ ___________________________________________________________________________
37 Kinetic energy= ½ mass x velocity2 In symbol: (K.E=1/2 mv2 ) The units used are: Mass (m) = kilograms, kg (Velocity)2 (v2 ) = meter2 /second2 , m2 /s2 Activity 2: Kick Here! Kick There! KINETIC Anywhere! Directions: Study table C and D below and analyze the different quantities given. Then, answer the questions that follow. Table C: KE of the object when the mass increases and the square of its velocity remains the same Table D: KE of the object when the mass remains the same while the square of its velocity increases 1. In table A, what happens to the K.E of the object when mass increases but the velocity of the object remains the same? ______________________________________________________________________ 2. In table B, what happens to the K.E of the object when the velocity doubles but the mass of the object remains the same? ______________________________________________________________________ 3. What happens to the K.E of an object when the object is massless? When velocity is zero? What can you infer in this situation? ______________________________________________________________________ ______________________________________________________________________ Mass, kg (Velocity)2 , m2 /s2 K.E (K.E=1/2 mv2 ), J 0 2 0 1 2 2 2 2 4 Mass, kg (Velocity)2 , m2 /s2 K.E (K.E=1/2 mv2 ), J 2 0 0 2 2 4 2 4 16
38 4. What are the factors that affect the K.E of an object? ______________________________________________________________________ 5. How can mass and velocity affect the K.E of an object? ______________________________________________________________________ 6. What is the relationship of mass and velocity to the K.E of an object? ______________________________________________________________________ 7. Give at least two (2) applications/situations where we can apply K.E in our real life. ______________________________________________________________________ ______________________________________________________________________ Activity 3: Jack and Hill Directions: Identify the relationship between Kinetic Energy and Potential Energy of the cyclist at each position as shown in the illustration below. Choose the letter of your answer from the given choices. Credits: https://www.google.com/search?q=comic+strip+on+potential+and+kinetic+energy+png 1. ___________ 2. ___________ 3. ___________ 4. ___________ 1 2 3 A. K.E increases while P.E decreases. B. P.E is at a minimum. C. K.E decreases while P.E increases. D. P.E is at a maximum.
39 Activity 4: Game of Energetics Adapted from: theeducationcenter.com by PINTEREST Directions: In the following competition, Team Potential and Team Kinetic will each try to emerge as the winner. To find out who comes out on top, read the description of each player’s energetic action. Then check the correct box to indicate which team can take credit for the action. When finished, total the scores and show the final results on the scoreboard. ENERGY SCOREBOARD POTENTIAL KINETIC Team Potential Team Kinetic 1. Player 11’s rock is at the top of a hill. 2. Player 22 aims a stretched rubber band at the target. 3. Player 33 shoots her rubber band toward the goal. 4. Player 14 waits, with his bow pulled back, to release the arrow. 4. Player 35 kicks the football. 5. Player 26 hits the golf ball with his club. 6. Player 17 releases the arrow from his bow. 7. Player 48 pushes the rock over the cliff 8. The pitcher stands with his arm above his head and the ball in his hand. 10. Player 50 is holding a 2-kg rock 1.5m above the floor.
40 Activity 5: PE and KE are PROBLEMatic Directions: Solve the following problems. Show your solution. 1. What is the potential energy of a rock that weighs 150 Newtons that is sitting on top of a hill 200 meters high? 2. A 1500-kg automobile is traveling at a velocity of 120 m/s. How much kinetic energy does it possess? 3. A flower pot has a mass of 8kg on a window 30 meters from the ground. What is the gravitational potential energy of the flower pot in joules? 4. A toy car that weighs 15 kg is rolling down a hill with a velocity of 4.5 m/s. What is the kinetic energy of the toy car? 5. A 25 kg block is raised by a crane 4 meters above the ground. What is the potential energy of the block?
41 REFLECTION: 1. I learned that _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. I enjoyed most on _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. I want to learn more on _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
42 References: Campo, Pia C., et.al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. CK12 Foundation. “Potential Energy.” Accessed May, 2020. https://www.ck12.org/c/physics/ potential-energy/lesson/Potential-Energy-PHYS/?referrer=concept_details. Storyboard That. “Digital Storytelling.” Accessed May,2020. https://www.storyboardthat. com/.
43 Answer Key: Activity #1: How Potential am I? 1. The P.E also increases. 2. The P.E also increases. 3. Mass/Weight and height. 4. If the mass/weight and height increases, the PE also increases. 5. Mass/Weight of an object and its height is directly proportional to the P.E. 6. Sample answers: A yoyo before it is released. The wick in a candle. Fireworks before they are launched Activity #2: Kick here! Kick There! KINETIC anywhere! 1. If the mass is 0, the K.E is also zero. If the mass increases, the K.E also increases. If the mass doubles, the K.E also doubles. 2. If the velocity is 0, the K.E is also zero. If the velocity increases, the K.E also increases. If the velocity doubles, the K.E increases by a factor of four. That is because velocity is squared in the equation. 3. Mass and velocity. 4. If the object is massless, therefore the K.E is zero. If the object is not moving (zero velocity), therefore the K.E is also zero. If the mass increases, the K.E also increases. If the velocity doubles, the K.E increases by a factor of four. 5. Mass and velocity is directly proportional to the K.E of an object. 6. Sample answers: A moving tricycle or car. A flying paper airplane. A person riding a skateboard. Activity #3: Jack and Hill 1. C 2. D 3. A 4. B
44 Activity #4: Game of Energetics 1. P.E 6. K.E 2. P.E 7. K.E 3. K.E 8. K.E 4. P.E 9. P.E 5. K.E 10. P.E Activity #5: PE and KE are PROBLEMatic! 1. P.E=30,000 Joules 2. K.E= 90,000 Joules 3. P.E=2352 Joules 4. K.E= 151.875 Joules 5. P.E =980 Joules Prepared by: SHEELA A. APOSTOL EDGAR A. SADDUL Tuguegarao City Science High School ENERGY SCOREBOARD POTENTIAL KINETIC 5 5
45 SCIENCE 8 Name of Learner: __________________________________ Grade Level: ____________ Section: __________________________________________ Date: ____________________ LEARNING ACTIVITY SHEET When Hotter, Faster or Slower? Background Information for the Learner Sound waves need a medium to be transmitted. The medium could be a solid, liquid or gas. Its speed through the medium is affected by some factors. One of the factors is temperature. When sound travels through dry air, its speed increases by 0.6 m/s per 1o C increase in temperature. The speed of sound at a certain temperature in air can be computed using the formula: v = 331m/s + 0.6m/s/o C (T). Where v is the speed of sound in air, 331 m/s is the speed of sound at 0 o C, 0.6m/s/o C is the increase in speed of sound per o C increase in temperature, and T is the temperature of air. In your past lessons about sound, you have learned that sound energy travels from one particle to another. As the temperature increases, the particles vibrate faster resulting to more collisions per unit time. With more collisions per unit time, sound energy is transferred more efficiently, and travel quickly. In this activity, you will be investigating the effect of temperature to the speed of sound by doing different activities. Learning Competency and Code Investigates the effect of temperature to speed of sound through fair testing (S8FE – Ie – 25)
46 Activity 1. 3 Pics, 1 Concept Directions: The diagram below shows the air temperature in some areas, and the speed of sound. Study the diagram and answer the questions that follow. Source: www.nde.ed.org/EducationResources/HighSchool/Sound/tempandspeed.html Questions: 1. What is the speed of sound at the lowest temperature given in the diagram? _________________________________________________________________ 2. What is the speed of sound at the highest temperature given in the diagram? _________________________________________________________________ 3. At what temperature where sound travels the slowest? _____________________ 4. At what temperature where sound travels fastest? _________________________ 5. How does temperature affect the speed of sound? _________________________________________________________________
47 Activity 2. Solve for v Directions: The table below shows some cities in the world and their recorded air temperature in a certain time. Using the formula v = 331m/s + 0.6m/s/o C (T), calculate the speed of sound in each given location. Record your answers in the table. Show your complete solution. Start with the given quantities, required or unknown, formula, solution, and final answer. A rubric will be used to evaluate your answers. Then, answer the questions that follow. Table 1. Speed of sound in some cities in the world at different temperature Location Temperature in ºC Speed (v) of sound in m/s Sapporo, Japan -4 Madrid, Spain 6 Wuhan, China 15 Tuguegarao City, Philippines 40 Write your complete solutions here: Sapporo, Japan Given: Required: Formula: Solution: Answer: Madrid, Spain Given: Required: Formula: Solution: Answer:
48 Wuhan, China Given: Required: Formula: Solution: Answer: Tuguegarao City, Philippines Given: Required: Formula: Solution: Answer: Questions: 1. a. What city is relatively the hottest? __________________________________________ b. What is the speed of sound in this city? ______________________________________ c. Is it relatively the fastest? or slowest? ________________________________________ 2. a. What city is relatively the coldest? __________________________________________ b. What is the speed of sound in this city? ______________________________________ c. Is it relatively the fastest? or slowest? ________________________________________ 3. What is the effect of temperature to the speed of sound in air? _______________________ _________________________________________________________________________ Rubric for the problem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement
49 Activity 3. Hotter, Faster Directions: Sound waves also travel through solid, and liquid like water. The table below shows the speed of sound in water at different temperature. Study the data, and answer the questions that follow. Table 2. Speed of sound in water at different temperature Temperature in ºC Speed of Sound in water (m/s) 0 1402 20 1482 100 1543 Questions: 1. What happens to the speed of sound in water when the temperature increases? __________________________________________________________________ 2. What happens to the speed of sound in water when the temperature decreases? __________________________________________________________________ 3. Based on the table, what is the effect of temperature to the speed of sound in water? ___________________________________________________________________
50 Activity 3. Hotter, Faster Directions: Sound waves also travel through solid, and liquid like water. The table below shows the speed of sound in water at different temperature. Study the data, and answer the questions that follow. Table 2. Speed of sound in water at different temperature Temperature in ºC Speed of Sound in water (m/s) 0 1402 20 1482 100 1543 Questions: 1. What happens to the speed of sound in water when the temperature increases? __________________________________________________________________ 2. What happens to the speed of sound in water when the temperature decreases? __________________________________________________________________ 3. Based on the table, what is the effect of temperature to the speed of sound in water? ___________________________________________________________________
51 Activity 4. #Relationship Directions: Given the data in Table 3 below, draw the graph properly and find out the relationship between the Temperature and the Speed of Sound. A Rubric will be used to check your graph. Table 3. Speed of sound at different temperature. Temperature in o C (Dry Air) Speed of Sound in m/s 0 331 9 336 22 344 30 349 44 357 Questions: 1. What is the shape of the graph? _____________________________________________________________________ 2. How does temperature affect the speed of sound? _____________________________________________________________________ 3. How does the speed of sound related to the temperature of a medium? _____________________________________________________________________ Relationship Between Temperature and Speed of Sound Temperature (o C) Speed of Sound (m/s)
52 4. At what temperature where the particles of air vibrate the fastest? ________________ 5. At what temperature where the particles of air vibrate the slowest? _______________ 6. Explain your answer in number 4 and 5 briefly. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 7. At what condition where the speed of sound becomes zero? What is its possible implication? ____________________________________________________________________ ____________________________________________________________________ Rubric for the graph 5 4 3 2 1 Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in either X or Y axes are properly scaled. Numbers in both X and Y axes are not properly scaled. 5 data points are properly plotted. 4 data points are properly plotted. 3 data points are properly plotted. 2 data points are properly plotted. 1 or no data point is properly plotted. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. A line is drawn from one point to another point. No line is drawn Reflection: 1. I learned that _________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 2. I enjoyed most on _____________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 3. I want to learn more on _________________________________________________ ____________________________________________________________________ ____________________________________________________________________
53 References: Campo, Pia C., et. al. 2003. Science-Grade 8. Learner’s Module. Pasig City. Department of Education. Young, Hugh D. and Freedman, Roger A. 2002. University Physics with Modern Physics. Singapore 629733. Pearson Education Asia Pte Ltd. www.nde.ed.org/EducationResources/HighSchool/Sound/tempandspeed.html
54 Answer Key: Activity 1. “3 Pics 1 Concept” 1. What is the speed of sound at the lowest temperature given in the diagram? 330.4 m/s 2. What is the speed of sound at the highest temperature given in the diagram? 358.0 m/s 3. At what temperature where sound travels the slowest? - 1 ºC 4. At what temperature where sound travels fastest? 45 ºC 5. How does temperature affect the speed of sound? The higher the temperature, the faster the speed of sound; or The lower the temperature, the slower the speed of sound Activity 2. “Solve for v” Sapporo, Japan Given: T = -4 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (-4 ºC) Answer: v = 328.6 m/s Madrid, Spain Given: T = 6 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (6 ºC) Answer: v = 334.6 m/s Wuhan, China Given: T = 15 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (15 ºC) Answer: v = 340.0 m/s Tuguegarao City, Philippines Given: T = 40ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (40 ºC) Answer: v = 355.0 m/s Rubric for the problem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement
55 Table 1. Speed of sound in some cities in the world at different temperature Location Temperature in ºC Speed (v) of sound in m/s Sapporo, Japan -4 328.6 Madrid, Spain 6 334.6 Wuhan, China 15 340.0 Tuguegarao City, Philippines 40 355.0 1. What city is relatively the hottest? Tuguegarao City, Philippines What is the speed of sound in this city? 355.0 m/s Is it relatively the fastest? Or slowest? Fastest 2. What city is relatively the coldest? Sapporo, Japan 3. What is the speed of sound in this city? 328.6 m/s Is it relatively the fastest? Or slowest? Slowest 4. What is the effect of temperature to the speed of sound in air? The higher the temperature, the faster the speed of sound; or The lower the temperature, the slower the speed of sound Activity 3. “Hotter, Faster” 1. What happens to the speed of sound in water when the temperature increases? The speed of sound in water increases when the temperature increases. 2. What happens to the speed of sound in water when the temperature decreases? The speed of sound in water decreases when the temperature decreases. 3. Based on the table, what is the effect of temperature to the speed of sound in water? Sound travels faster when the temperature increases; or Sound travels slower when the temperature decreases. Activity 4. “#Relationship”
56 Rubric for the graph 5 4 3 2 1 Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in either X or Y axes are properly scaled. Numbers in both X and Y axes are not properly scaled. 5 data points are properly plotted. 4 data points are properly plotted. 3 data points are properly plotted. 2 data points are properly plotted. 1 or no data point is properly plotted. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. A line is drawn from one point to another point. No line is drawn 1. What is the shape of the graph? Straight line graph (slanting to the right) 2. How does temperature affect the speed of sound? As the temperature increases, the speed of sound increases 3. How does the speed of sound related to the temperature of a medium? Speed of sound is directly proportional to the temperature. 4. At what temperature where the particles of air vibrate relatively the fastest? Particles vibrate fastest at 44 ºC 5. At what temperature where the particles of air vibrate relatively the slowest? Particles vibrate fastest at slowest at 0 ºC. 6. Explain your answer in number 5 briefly. The higher the temperature, the higher the kinetic energy of the particles, the faster they vibrate. 7. At what condition where the speed of sound becomes zero? What is its possible implication? The speed of sound becomes zero when the particles of a medium stop vibrating, having zero kinetic energy. This means that no sound can travel through the medium, no sound can reach the ears of the receiver, no sound can be heard. Prepared by: GEMMA U. PACAMALAN Cagayan National High School REOWIN PALATTAO Gosi National High School
57 SCIENCE 8 Name of learner: ____________________ Grade level: _______________ Section: ___________________________ Date______________________ LEARNING ACTIVITY SHEET Colors of Light Background Information for the Learners Have you seen a rainbow? When can you see a rainbow? A rainbow displays a unique band of colors. The colors we see are the result of sunlight hitting water drops where reflection, refraction and dispersion forms a rainbow. Water drops act as tiny prism separating sunlight into bands of colors. The colors of light are distinguished from each other by their different wavelengths and frequencies. The colors of light depend on their frequencies and wavelengths. Wavelength is the distance between two identical adjacent points in a wave while frequency is the number of waves that pass a fixed point in a unit time. The wavelengths and frequencies of the colors of light vary. The higher the frequency of the color of light, the greater is its energy. As the frequency of the color of light increase, the energy also increases. Red has the least frequency with the least energy and violet has the highest frequency and the highest energy. The spectral colors have the following characteristics; frequency, wavelength and energy. The color of light with longer wavelength travels slowly and has low frequency and energy. The color of light with shorter wavelength travels faster and has higher frequency and energy. Learning Competency and Code: Explain the hierarchy of colors in relation to energy. (S8FE-If-27-28)
58 Activity 1. Complete Me Directions: Unscramble the word/s to get the correct term and fill the appropriate blanks to complete the statements below. itwhehltig deeps dgbinen loroc repsidoin pmetsrcur calticriganle flecnoiter velewagnth lotatlanterniflecnoiter 1. Lights of different frequencies make up __________________. 2. ____________________band of colors obtained by dispersion of light. 3. Refraction is the _____________ of light when it travels from one medium to another of different optical densities. 4. __________________________ the process of separating light into a band of colors. 5. ______________________occurs when the angle of incidence is greater than the critical angle. 6. _________________property of light waves which is dependent on the frequency or wavelength of radiation that reaches the eye. 7. _______________________the angle of incidence in the denser medium resulting in angle of refraction of 900 . 8. ______________________property of light responsible for the formation of colors. 9. The ________________ of the different colors changes as it passes through the prism. 10. __________________ is the turning back of light when it hits a barrier.
59 Activity 2. Who Am I? Directions: The diagram below shows the separation of white light into different colors as it hits the prism. Color the refracted rays. Then, answer the questions that follow. 1. What do you call the process of separating white light into its components? __________________________________________________________________ __ 2. Which color is bent the most? ____________________________________________ 3. Which color is bent the least? _____________________________________________ 4. What do you call the bond of colors produced? _______________________________ 5. What are the component colors of a white light? ______________________________ _____________________________________________________________________ 6. What name or code could you give according to the hierarchy of colors? __________ Activity 3. Fact or Bluff Directions: Study the illustrations of wavelengths below. Given the following color descriptions, write Fact on the blank if it is true while Bluff if it is false. VIOLET RED _________1. Violet has longer wavelength. _________2. Red has shorter wavelength. _________3. Violet and red have the same wavelengths. _________4. Red has longer wavelength. _________5. Violet has shorter wavelength.
60 Activity 4. Relate Me Directions: Draw and color the rainbow with the corresponding bond of colors in relation to its wavelength. 1. Which color represents the longest arc/ wavelength? ________________________ 2. Which color represents the shortest arc/ wavelength? ________________________ 3. What color appears at the top of the rainbow? Why? ________________________ ___________________________________________________________________ 4. What color appears at the bottom of the rainbow? Why? ______________________ ____________________________________________________________________ 5. Explain how wavelength is related in the position of colors in a rainbow? ____________________________________________________________________ ____________________________________________________________________
61 Activity 5. Color Me Directions: Color the spectrum wheel based on the given corresponding frequency, wavelength and energy.
62 Activity 6. Fill Me Directions: Using the illustration of Color Wheel in Activity 5, fill out the table with the corresponding wavelength, frequency and energy. Table 1 Frequency (Hz) Wavelength (m) Energy (eV) Red Orange Yellow Green Blue Violet Activity 7. Compare Me Directions: Study Table 1 to answer the questions below. 1. Compare the following color bonds using the descriptions (lower, higher, shorter, and longer). a. Red is _______________ in wavelength than violet. b. Yellow is _______________ in energy than blue. c. Violet is _______________ in frequency than red. d. Red is _______________ in energy than violet. e. Blue is _______________ in wavelength than red. 2. Which of the colors have the following characteristics? a. Longest wavelength? ______________ b. Shortest wavelength? ______________ c. Lowest frequency? ________________ d. Highest frequency? _______________ e. Highest energy? __________________ f. Lowest energy? __________________
63 Activity 8. Link Me Directions: Use the illustration of electromagnetic spectrum in answering the questions that follow. https://www.miniphysics.com/electromagnetic-spectrum_25.html 1. Does the frequencies of the colors of light increase from red to violet? ___________ 2. What did you observe about the wavelengths and frequencies of the colors of light? _____________________________________________________________________ 3. How is frequency related to energy of colors of light? _____________________________________________________________________ _____________________________________________________________________ 4. What did you observe about the corresponding energies from red to violet? _____________________________________________________________________ _____________________________________________________________________ 5. How will you explain the heirarchy of colors in relation to energy? _____________________________________________________________________ _____________________________________________________________________ Reflection: 1. I learned that __________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. I enjoyed most on ______________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. I want to learn more on __________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
64 References: Campo, Pia C., et. al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. Rabago, Lilia M., Ph.D.,et.al. 2001. Science and Technology IV: Physics Textbook for Fourth Year. Quezon City. Vibal Publishing House. Sotto, R.L., et. al. 2003. Science in Today’s World: Physics. Manila: Rex Bookstore, Inc. https://www.miniphysics.com/electromagnetic-spectrum_25.html https://www.youtube.com/watch?v=ASEdGwpyn58&t=4s https://www.youtube.com/watch?v=TvT3g8kU6SQ
65 Answer Key: Activity 1- Complete Me 1. White light 2. Spectrum 3. bending 4. Dispersion 5. Total internal reflection 6. Color 7. Critical angle 8. Wavelength 9. Speed 10. Reflection Activity 2-Who am I? 1. Dispersion 2. Violet 3. Red 4. Spectrum 5. Red, orange, yellow, green, blue, indigo, violet 6. ROY G BIV Activity 3- Fact or Bluff 1. Bluff 2. Bluff 3. Bluff 4. Fact 5. Fact Activity 4 – Relate Me 1. Red 2. Violet 3. Red -- Red has longer arc / wavelength 4. Violet – Violet has short arc//wavelength
66 Activity 5 Color Me Activity 6 – Fill Me Frequency (THz) Wavelength (nm) Energy (eV) Red 422 700 1.77 Orange 484 620 2.00 Yellow 517 580 2.14 Green 566 530 2.34 Blue 638 470 2.6 Violet 744 400 2.95
67 Activity 7- Compare Me 1. a. longer b. lower c. higher d. lower e. shorter 2. a. Red b. Violet c. Red d. Violet e. Violet f. Red Activity 8- Link Me 1. Yes. 2. The wavelengths and frequencies of the colors of light vary. The wavelength decreases from red to violet while the frequency increases from red to violet. 3. The higher the frequency of the color of light, the greater is its energy. 4. As the frequency of the color of light increase, the energy also increases. Red has the least frequency with the least energy and violet has the highest frequency and the highest energy. 5. The spectral colors have the following characteristics; frequency, wavelength and energy. The color of light with longer wavelength travels slowly and has low frequency and energy. The color of light with shorter wavelength travels faster and has higher frequency and energy. Prepared by: VENIE N. DE LEON Cagayan National High School
68 SCIENCE 8 Name: ____________________ Grade Level: _________________ Date: _____________________ Score: ______________________ LEARNING ACTIVITY SHEET Heat and Temperature Background Information for Learners Heat is often associated with temperature. In a typical life, one has to cook food using wood or other fuels like LPG. Burning fuels generate heat. Heat generated, on the other hand, is associated with increase in temperature. However, this is not always the case. Though heat and temperature are related to each other, they are two different concepts. The difference between these terms has something to do with the movement between atoms and molecules – the kinetic energy of substances. The Kinetic Molecular Theory of matter states that matter consists of particles that are constantly moving. Take into consideration the Figure 1 below. A B Figure 1: Boiling a 500 ml of water (A) vs 100 ml of water (B) Figure 1 above shows that regardless of the volume of water, the temperature of the two set-ups remain the same upon reaching their boiling points. There are more water molecules in beaker A containing 500 ml water, thus, requiring longer time for it to boil than 100 ml of water in beaker B. The higher the number of water molecules, the higher also is its heat /internal energy. Heat Temperature = 1000 C Temperature = 1000 C Heat
69 Temperature is the measure of hotness or coldness of a body and is measured by the use of thermometer (Madriaga et. al, 2013).It is the average kinetic energy which indicates the direction in which heat flows. Heat, on the other hand, is the energy that transfers from a body of higher temperature to another body of lower temperature through molecular collisions and cannot be directly measured. When heat is absorbed or given off by an object, its temperature changes. If heat is added to an object, the particles of the object move faster and the body’s temperature increases. If heat is transferred or removed from an object, the particles move slower and the body’s temperature decreases. As the thermal energy of a substance increases, its particles spread out and the substance expands in a process known as thermal expansion. Almost all materials expand when heated and contract when cooled (Padua et.al, 2010). Moreover, phase changes occur when heat is added to or removed from an object. Different materials also have the ability to absorb or release heat that result in temperature change. The amount of heat required by a material to increase its temperature of one-unit mass of a given material by one Celsius degree or by one Kelvin is called specific heat capacity (C). Padua et. Al, 2010). Learning Competency and Code Differentiate between heat and temperature at the molecular level. (S8FE-Ig-29)
70 Activity 1: Word Hunt Directions: Search the words being described in the sentences below. The answers may be found horizontally, vertically or diagonally. 1. It is a thermal sensor that measures temperature. 2. A process when matter changes from state to another. 3. A measure of the warmth of an object or substance. 4. A measure of relatively low temperature of an object or substance. 5. The energy that is contained within a system that is responsible for its temperature. 6. Increase in the size of a material. 7. The decrease in the size of a material. Source: Word Search Puzzle. Accessed June 8, 2020. Retrieved from http://puzzlemaker.discoveryeducation.com/code/BuildWordSearch.asp
71 Activity 2: Heat vs. Temperature Directions: Choose the corresponding characteristics of heat and temperature on the choices given below. Write the letter of the correct answer on the space provided. A. It is a measure of hotness and coldness of a body. B. It is a form of energy that flows from a hotter region to the cooler region. C. It is measured in degree Celsius (o C), Fahrenheit (o F) or Kelvin (K). D. It is measured in calories (cal) or Joules (J). E. It depends on the speed of particles, the size and type of object. F. It does not depend on the mass of the object. Activity 3: Modified True or False Directions: Write TRUE if the statement is correct. Write FALSE if the statement is wrong and change the underlined word/s to make the statement correct. Write your answer on the space provided. ___________________________ 1. Liquid expands when heated. ___________________________ 2. Thermal expansion applies to solid and liquid. ___________________________ 3. Materials take up more space when heated ___________________________ 4. Solid expands more than liquid when heated. ___________________________ 5. The particles of liquid move freely when heated. ___________________________ 6. Water expands when cooled. ___________________________ 7. Molecules move far each other during contraction. ___________________________ 8. Only the spaces between particles changes during expansion and contraction. ___________________________ 9. Electrical wires could sag during hot days. ___________________________ 10. Tight bottle cap can easily open by putting it in hot water. What are the differences between Heat and Temperature? Heat • __________________ __________________ • __________________ __________________ • __________________ __________________ Temperature • _________________ _________________ • _________________ _________________ • _________________ _________________
72 Activity 4: Going Phase Change Directions: Write the letter of the missing data on the graph below showing the phase change of water. Choose your answer on the box. Then, answer the questions that follow. Phase change of water as heat is added Source: “Phase Change: Evaporation, Condensation, Freezing, Melting ...” Accessed June 4, 2020. https://spiral.ac/lesson-plan-ideas/clips/lessons/phase-change-evaporation- condensation-freezing-melting-sublimation-deposition. 1. What happens to the temperature and heat energy of a substance during a change of state? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. What happens when heat is added once the phase change is complete? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Heat Energy 5. ______________ 3._______ 6. Temperature 0o C 2. ________ 100o C A. vaporization D. G. melting B. E. ice C. sublimation F. liquid steam 4.________ _____ 1.________ _____
73 3. What can you infer about the relationship between phase change and heat energy? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Activity 5: Graph It Down Directions: Analyze the data below of the temperature change of different substances in a given time. Using the graph, plot the time in the x-axis vs the given values for each substance in the y-axis. Then, connect the graph of each of the three substances. Create a line graph for each substance below and answer the questions given. Use colored pen or crayon to connect the graph following the color coding below: Blue - water Yellow- sand Red - Iron Time (minutes) Temperature of the Substances (o C) Water Sand Iron 0 (initial) 25.0 o C 25 o C 25 o C 15mins 26.0o C 30o C 35 o C 30mins 27.5o C 35o C 45 o C 45mins 28.9 o C 40o C 55 o C 60mins 30.0 o C 45o C 65 o C Source: “Specific Heat Worksheet Answers.” Homeschooldressage.com, February 25, 2018. http://homeschooldressage.com/specific-heat-worksheet-answers/ A. Temperature vs. Heating Time Graph
74 B. Answer the following questions: 1. What is the order of the substances based on the time required to heat from slowest to fastest? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ 2. Which of these substances require more heat to increase in temperature? ___________________________________________________________________________ _________________________________________________________________________ 3. Which substances require more time to increase in temperature? ___________________________________________________________________________ _________________________________________________________________________ 4. When you boil water using a pot on the stove, which heats faster, the iron pot or the water? Explain your answer. __________________________________________________________________________ ___________________________________________________________________________ _________________________________________________________________________ 5. When you go to the beach you noticed that the sand is hotter than water although both are exposed under the heat of the sun. Why do you think this happens? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ 6. Based on the graph, which of the three substances has the highest specific heat capacity? Which substance has the lowest specific heat capacity? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ Reflection: 4. I learned that _________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ 5. I enjoyed most on ____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ 6. I want to learn more on _________________________________________________
75 _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ References Madriaga, Estrellita A, Meliza P Valdoz, and Jonna M Abistado. 2013. Science Links. First Ed. Sampaloc, Manila, Philippines: Rex Book Store, Inc. Ocampo, Pia C. et.al. 2013 Science 8 Learner's Module. 1st ed. Pasig City, Philippines: Department of Education. Padua, Alicia L, and Ricardo M Crisostomo. 2010. Practical and Explorational Physics. Second ed. Quezon City, Philippines: Vibal Publishing House, Inc. Santos, Gil Nonato C., and Alfonso C. Danac. 2006. i-Physics (Investigatory Physics). Firsted. Sampaloc, Manila, Philippines: Rex Book Store, Inc. Website “Ninth Grade Lesson Introduction to Specific Heat ...” Accessed June 3, 2020. Retrieved from https://betterlesson.com/lesson/640676/introduction-to-specific-heat “Phase Change: Evaporation, Condensation, Freezing, Melting ...” Accessed June 4, 2020. Retrieved from https://study.com/academy/lesson/phase-change-evaporation-condensation-freezing- melting.html “Specific Heat Worksheet Answers.” Homeschooldressage.com, February 25, 2018. Retrieved from http://homeschooldressage.com/specific-heat-worksheet-answers/ “The Physics Classroom Tutorial.” The Physics Classroom. Accessed June 3, 2020. Retrieved from https://www.physicsclassroom.com/Class/thermalP/u18l1d.cfm Velez, Sierra. “Blendspace Created For Physical Science By Sierra Velez ...” Blendspace Created For Physical Science. Accessed June 3, 2020. Retrieved from https://www.tes.com/lessons/AX17cZ8TBxwrrg/blendspace-created-for-physical- science-by-sierra-velez “What Is Thermal Energy? (Article) | Khan Academy.” Accessed June 4, 2020. Retrieved from https://www.khanacademy.org/science/physics/work-and-energy/work-and-energy- tutorial/a/what-is-thermal-energy Word Search Puzzle. Accessed June 8, 2020. Retrieved from http://puzzlemaker.discoveryeducation.com/code/BuildWordSearch.asp
76 Answer Key Activity 1: Word Hunt 1. Temperature 2. Phase change 3. Hotness 4. Coldness 5. Thermal Energy 6. Expansion 7. Contraction Activity 2: Heat vs. Temperature Heat- answer B, D and E Temperature- answer A, C and F Activity 3: Modified True or False 1. TRUE 6. heated 2. Solid, Liquid and Gas 7. Move closer 3. TRUE 8. Fact 4. TRUE 9. Fact 5. TRUE 10. Fact Activity 4: Going Phase Change A. 1. E. Ice 5. A. vaporization 2. B. 6. D. 3. H. melting 4. F. liquid B. 1. During a change of state, the temperature of a substance remains constant, while the thermal energy changes. 2. Once the phase change is complete, adding more heat causes the temperature to increase. 3. Heat energy is needed in phase change.
77 Activity 5: Graph it Down A. Temperature vs. Heating Time Graph B. 1. Water- Sand- Iron 2. The water requires more heat to increase in temperature. 3. The water requires more time to increase in temperature. 4. The iron pot heats faster than the water because it requires less energy to heat up. It has lower specific heat capacity. 5. The sand is hot and the water is cold because the sea has to absorb more heat to raise its temperature than the sand. Water has higher specific heat capacity than the sand. 6. Water has the highest specific heat capacity and iron has the lowest specific heat capacity. Prepared by: KAREN C. GACUTAN Linao National High School
78 SCIENCE 8 Name of Learner: _______________________ Grade Level: _______________ Section: _______________________________ Score: ____________________ LEARNING ACTIVITY SHEET Relationship between Voltage and Current Background Information for Learners Electricity is almost an indispensable part of our lives. Lighting, heating, transportation, and communication are all dependent on it. When you connect an electric fan to an outlet, you are assembling and using an electric circuit. It consists of a source of electrical energy, connecting wires and a load. The three electrical quantities are current, I measures in amperes(A), voltage, V measures in volts(V) and resistance, R measures in ohms ( ). In an electric circuit, the voltage is the work done in moving or pushing the charged electrons (current) from one point to another in the circuit. The current in the circuit, on the other hand, is responsible for illuminating the bulb or in rotating the electric fan as the case maybe. The amount of current in the circuit is dependent upon the voltage applied. This amount of current can be indicated by the intensity of brightness in the case of a lighted bulb. Voltage, V is directly proportional to current, I, that is V I or V = k I Where k, the proportionality constant, is the slope of the V vs I graph. This constant k is equal to the resistance, R of the circuit, so R = V/I The unit of electrical resistance is defined as R = volt (V)/ampere (A) or ohm ( ) 1 = 1 V/A The relationship between voltage, current and resistance is known as Ohm’s Law, named after George Simo Ohm, who pioneered the study of such relation. Ohm’s law states that current, I is directly proportional to the voltage, V and inversely proportional to the resistance, R. In equation: I = V/R
79 Most electric circuits we see operate on more than one load called multiple load circuits. For instance, when you turn on light in the dining room, lamps in your bedroom remain unlighted, but if you remove one light bulb from Christmas bulbs, the other bulbs no longer light. Light bulbs in houses are connected differently from that of Christmas bulbs. The connection of light bulbs at home is called parallel while the Christmas light bulbs is in series. A series connection has two or more loads but current flows through a single conducting path while parallel connections has more than one path for current to flow. The figure below shows the differences between series and parallel connections. Fig.1: Series Connection Fig. 2: Parallel connection Applying Ohm’s law for series and parallel connections consider these equations below. Series connections IT = I1 = I2 = I3 … VT = V1 + V2 + V3 + … RT = R1 + R2 + R3 + … Parallel connections IT = I1 + I2 + I3 + … VT = V1 = V2 = V3 … _1_ = _1_ + _1_ + _1_ + … RT R1 R2 R3 This learning activity sheet will help you understand more of the relationship between voltage and current. Learning Competency with code Infer the relationship between current and voltage. (S8FE-Ig-30)
80 Activity 1: Voltage vs. Current Directions: Complete the chart below to show comparison between voltage and current. Voltage Current Symbol Unit SI Unit Definition Relationship Voltage is the cause and current is the effect. Voltage can exist without current. Measuring Instrument Field created An electrostatic field In a series connection Current is the same through all components connected in series. In a parallel connection Voltages are the same across all components connected in parallel.
81 Activity 2: The Brighter, the Better Study the circuit diagrams below showing identical bulbs connected to a circuit with different number of batteries. Then, answer the questions that follow. Figure 3. Figure 4 . Figure 5. 1. Which configuration is the light brightest? ____________________________ 2. Which configuration has the greatest amount of current? _________________ 3. Which configuration is the light dimmest or least bright? _________________ 4. Which configuration has the least amount of current? ___________________ 5. If a single battery has a voltage of I.5 volts, what is the voltage of the circuit in figure 1? _____________________ 6. What is the total voltage of the circuit in figure 2? ______________________ 7. What is the total voltage of the circuit in figure 3? ______________________
82 Activity 3. “Follow Me”, Relationship between Current and Voltage The figure below is the Experimental Set-up for finding the relationship between voltage and current. Analyze the data taken from the experiment and do the instructions that follow. Fig. 6 Data taken from the experiment: Table 1. Comparative Values of Voltage and Current at Fixed Resistance Number of Dry cells Voltage,V (Volts) Current, I (Ampere) Voltage,V /Current, I (Volt/Ampere) 1 1.5 0.15 2 3.0 0.30 3 4.5 0.45 4 6.0 0.60 1. Fill-up the fourth column of the table by dividing voltage, V by current, I. 2. Using the graph below, plot the data of voltage, V against Current,I.
83 3. Draw a line of best-fit using the plotted points. 4. Describe the graph? ________________________________________________ 5. What does the graph indicate? ________________________________________ 6. What becomes of current, I as the voltage, V is increased?___________________ 7. What becomes of current, I as the voltage, V is decreased? __________________ 8. How will you describe the quotient when you divide voltage by current in column 4 of Table 1? 9. What electrical quantity represents this in the circuit? 10. What can you infer/conclude about the relationship between voltage and current for the same/constant load or resistor? __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Activity 4: Oh My Ohm’s Law Directions: Solve the following problems applying Ohm’s Law in the circuit. Show your complete solution. Start with the given quantities, required or unknown, formula, solution, and final answer. A rubric will be used to evaluate your answers. 1. How much current flows in an electric iron having a resistance of 20 when connected across 220-V line? 2. An electric heater uses 4A when 220-V are applied to its terminals. Determine its resistance.
84 3. What is the voltage across an electric hot plate which is draws 11A from the line when its hot resistance is 20 ? 4. What is the resistance of the coil of wire in an electric stove if it is connected to a 220V line and the current passing through it is 8A? 5. How much current flows through a lamp with a resistance of 75 when it is connected to a 220V line? 6. What is the resistance of a lamp which allows 10.9A when 220V is applied to it? 7. How much current would a 12 bread toaster draw when connected to a 220V outlet? 8. A resistor is connected to a 12V battery. The ammeter in the circuit reads 2A. What is the value of the resistance?
85 9. If the voltage in the circuit were doubled, what would happen to the current in the circuit? 10. If current in the circuit doubles of the same voltage, what will happen to the resistance in the circuit? Activity 5. Resistivity Affects Conductivity Directions: Use the table below to answer the questions that follow. Table 2: Resistivity of some materials at 200 C. Material Resistivity ( Silver 1.47 x 10-8 Copper 1.72 x 10-8 Gold 2.44 x 10-8 Aluminum 2.63 x 10-8 Tungsten 5.51 x 10-8 Steel 20.0 x 10-8 Mercury 95.0 x 10-8 Nichrome 100.0 x 10-8 Carbon 3.5 x 10-5 Source: Young, Hugh D. and Roger A freedom. University Physics with Modern Physics. 11th Ed. Pearson Wesley. 2004 1. Which of the given materials have the least resistivity? ________________________ As electrons flow through a conductor, they collide with the vibrating atoms of the conductor and these electrons transfer part of their energy to the atoms resulting to kinetic energy increases as manifested in the increase in the temperature of a conductor. The collision of the electrons with the atoms limits the amount of current in the conductor and this property of material is called resistivity which describe as measure of the material’s resistance to the passage of current. On the other hand, conductivity is the degree to which a specified material conducts electricity.
86 2. Which of the given materials have the greatest resistivity? _____________________ 3. Explain why silver and gold are not used as household wirings despite of having the least resistivity. _____________________________________________________________________ _____________________________________________________________________ 4. Why is tungsten used as filament in lamps? _____________________________________________________________________ _____________________________________________________________________ 5. Why are copper wires used in household wiring? _____________________________________________________________________ _____________________________________________________________________ Activity 6. Connect Pa More Directions: Study the figures below to answer the following questions. Figure 7a Figure 7b 1. When you connect the four bulbs to a 12V power supply switch in series as shown in Figure 7a and turn the switch on, what happens to the other bulbs when you unscrew one light bulb? __________________________________________________________________________ 2. What if you will screw the one light bulb in Figure 7a, what do you observe? __________________________________________________________________________ 3. How do you describe this type of connection? __________________________________________________________________________ 4. When you connect the three bulbs to a 12V power supply as shown in Figure 7b and turn the switch on, what happens to the other bulbs when you unscrew one light bulb? ___________________________________________________________________________ ___________________________________________________________________________ 5. What if you will screw the one light bulb in Figure 7b, what do you observe? ___________________________________________________________________________
87 6. How do you describe this type of connection? ___________________________________________________________________________ 7. What is the difference between series connection and parallel connection based on your observations from the two set up? ___________________________________________________________________________ ___________________________________________________________________________ 8. What kind of connection is most practical at home? Why? ___________________________________________________________________________ ___________________________________________________________________________ 9. Why are electric meters connected in series with the rest of the circuits in the house? ___________________________________________________________________________ ___________________________________________________________________________ 10. Why is the main switch connected in series with the rest of the circuits in the house? ___________________________________________________________________________ ___________________________________________________________________________ Activity 7. Computation in a Connection Directions: Perform the indicated operations. Write the equations and solve for the unknown quantity. 1. Suppose there are four 30 bulbs are connected in series connected to a 220V line, what is the current in the circuit? Find the voltage drop in each of the four 30 bulbs. 2. You have five appliance connected in series as shown in the figure below. The refrigerator has a resistance of 20 , the TV set 10 , the radio 5 , the flat iron 75 and the electric stove 55 , what is a( total resistance in the circuit b) total current c) voltage drop in each appliance
88 a. total resistance in the circuit b. total current c. voltage drop in each appliance 3. Using the figure below, solve for: a. Resistance of the combination b. Current through the ciruit
89 c. Current through each resistor d. Voltage across each resistor 4. Refer to the figure below to solve for: a. Resistance of the combination b. Current through the combination
90 c. Current in each resistor d. Voltage across each resistor 5. Consider the circuit below, determine the following: a. Voltage across each load, b. Current through each load,
91 c. Total current through the circuit, and d. Total resistance Reflection: 1. I have learned that _________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. I enjoyed most on __________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 3. I want to learn more on ________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ References: Acosta Herma D et.a. 2015. Science 10 Learner's Module. 1st ed. Pasig City: Department of Education. Arciaga, Marco E et. Al. 2008. Exploring Science and Technology. Paranaque City: Diwa Scholastic Press Inc. Benetillo, Eulalia N et. al. 2009. Science and Technology IV Textbook for Fourth Year. Revised Edition. Quezon City: Book Media Press.
92 "Current vs Voltage." Diffen.com. Diffen LLC, n.d. Web. 13 Jun 2020.< https://www.diffen.com/difference/Current_vs_Voltage > Ocampo, Pia C. et.al. 2013. Science 8 Learner's Module. 1st ed. Pasig City: Department of Education. Padua L Alicia et. al. 2003. Practical and Exploration Physics. Quezon City: Vibal Publishing House Inc. Voltage, Current, Resistance and Ohm’s Law. Sparkfun Electronics. Accessed June 17, 2020. https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law Answer Key: Activity 1: Voltage vs. Current Voltage Current Symbol V I Unit V or volts or voltage A or Amp or amperage SI Unit 1 volt = 1 joule/coulomb. (V=W/C) 1 ampere =1 coulomb/second. Definition Voltage, also called electromotive force, is the potential difference in charge between two points in an electrical field. Current is the rate at which electric charge flows past a point in a circuit. In other words, current is the rate of flow of electric charge. Relationship Voltage is the cause and current is the effect. Voltage can exist without current. Current is the effect (voltage being the cause). Current cannot flow without Voltage Measuring Instrument Voltmeter Ammeter Field created An electrostatic field A magnetic field In a series connection Voltage gets distributed over components connected in series. Current is the same through all components connected in series. In a parallel connection Voltages are the same across all components connected in parallel. Current gets distributed over components connected in parallel.
93 Activity 2: The Brighter, The Better 1. Figure 5 2. Figure 5 3. Figure 3 4. Figure 3 5. 1 x 1.5 volts = 1.5 volts 6. 2 x 1.5 volts = 3.0 volts 7. 3 x 1.5 volts = 4.5 volts Activity 3: “Follow Me”, Relationship between Current and Voltage Table 1. Comparative Values of Voltage and Current at Fixed Resistance 1. 2 & 3 4. It is a straight line sloping upward to the right. 5. The graph indicates a direct relationship between Voltage and Current. 6. As the voltage, V is increased, the current, I is also increased. 7. As the voltage, V is decreased, the current, I is also decreased. 8. The answer is the same or constant Number of dry cells Voltage,V (Volts) Current, I (Ampere) Voltage,V/ Current, I 1 1.5 0.15 10 2 3.0 0.30 10 3 4.5 0.45 10 4 6.0 0.60 10
94 9. The electrical quantity being described in this constant value is called resistance, R. 10. Current, I is directly proportional or dependent to voltage, V. For the same load or resistor, a uniform increase or decrease in voltage would result in a uniform increase or decrease in current. Activity 4. Oh My Ohm’s Law 1. Given: R=20 , V=220v Required: I Formula: I = V/R Solution: I = 220V/20 Answer: I = 11V/ or 11A 2. Given: I=4A, V=220V Required: R Formula: R=V/I = Solution: R = 220V/4A Answer: R = 55V/A or 55 3. Given: I=11A, R=20 Required: V Formula: V = IR Solution: V=(11A)(20 ) Answer: V = 220A.V or 220V 4. Given: V=220V, I=8A Required: R Formula: R = V/I Solution: R = 220V/8A Answer: R = 27.5V/A or 27.5 5. Given: R=75 , V=220V Required: I Formula: I = V/R Solution: I = 220V/ 75 Answer: I = 2.93V/ or 2.93A 6. Given: I=10.9A, V=220V Required: R Formula: R = V/I Solution: R = 220V/10.9A Answer: R = 20.18V/A or 20.18 7. Given: R=12 , V=220V Required: I Formula: I = V/R Solution: I = 220V/12 Answer: I = 18.33V/ or 18.33A 8. Given: V=12V, I=2A Required: R Formula: R = V/I Solution: R = 12V/2A Answer: R = 66V/A or 6
95 9.The current, I in the circuit also doubled 10.The resistance, R in the circuit was reduced to 50% Activity 5. Resistivity Affects Conductivity 1. Silver 2. Nichrome 3. Because melting point of silver is very low and if used as wire it could catch fire in a house while gold is very soft to be used as wires and expensive. 4. Tungsten is used as filament in bulbs of lamps because it has the highest melting point and lowest vapor pressure of all metals and at temperatures over 1 6500 C it has the highest tensile strength. 5. Copper wires are used in household wiring because these have very low resistances and are good conductors. Their resistances are not affected much by temperature changes. Activity 6. Connect Pa More 1. The other bulbs will not light up. 2. The four light bulbs lighted. 3. Series connection 4. The two remaining bulb will still light up 5. The three bulbs lighted 6. Parallel connection 7. In Figure 7a when you unscrew one bulb, the remaining bulbs in the circuit will not light up because there is only one path for the electrons to flow in the circuit while in Figure 7b, when you unscrew one bulb, the remaining bulbs will still lighted because the flow of electrons in the circuit is separated. 8. Parallel connection is widely used at home because not all appliances can be used at the same time. 9. Electric meters are connected in series with the rest of the circuit in the house to be able to measure the total amount of electrical energy entering in the household. 10. The main switch is connected in series with the rest of the circuits in the house to be able to control electrical energy entering the house in case of emergency Activity 7: Computation in a Connection 1. RT = R1 + R2 + R3 + R4 RT = 30 30 + 30 + 30 = 120
96 IT = VT/RT = 220V/120 = 1.83A IT= I1 = I2 = I3 = I4 V1 = I1R1 = 1.83A(30 = 54.9V V2 = I2R2 = 1.83A(30 = 54.9V V3 = I3R3 = 1.83A(30 = 54.9V V4 = I4R4 = 1.83A(30 = 54.9V VT= V1 + V2 + V3 + V4 = 219.6Vor 220V 2. a) RT = RT + RT + RT + RT = 20 + 10 + 5 + 75 + 55 = 165 b) IT = VT / RT = 220V/165 = 1.33A c) Iref = V1R1 = (1.33A) ( 00 ) = 26.6V ITV = V1R1 = (1.33A) ( 10 ) = 13.3V Iradio = V1R1 = (1.33A) ( 5 ) = 6.65V Iflat iron = V1R1 = (1.33A) ( 75 ) = 99.75V Istove = V1R1 = (1.33A) ( 55 ) = 73.15V 3. a) 1/ RT =1/ R1 + 1/R2 + 1/R3 1/ RT =1/ 2 + 1/4 + 1/6
97 1/ RT =11 / 12 ( 11 RT)/ 11 = 12/11 RT = 1.09 b) IT = VT / RT = 6V / 1.09 = 5.50A c) I1 = V1//R1 I1 = 6V/ 2 IT = 3A I2 = V2//R2 I2 = 6V/ 4 IT = 1.5A I3 = V3//R3 I3 = 6V/ 6 IT = 1A d) VT = V1 = V2 = V3 = 220V 4. a) RT = R1 + R2 + R3 = 2 + 4 + 6 = 12 b) IT = VT / RT = 6V / 12 = 0.5A c) IT = I1 = I2 = I3 = 0.5A d) V1 = (I1 )(R1) = (0.5A) (2 ) = 1V V2 = (I2 )(R2) = (0.5A) (4 ) = 2V
98 V3 = (I3 )(R3) = (0.5A) (6 ) = 3V VT = V1 +V2 + V3 = 1V + 2V + 3V = 6V 5. a) Vt = V1 = V2 = V3 = 220V b) I1 = V1 / R1 = 220V / 240 = 0.92A I2 = V2 / R2 = 220V / 280 = 0.78A I3 = V3 / R3 = 220V / 300 = 0.73A c) It = I1 + I2 + I3 = 0.92A + 0.78A + 0.73A = 2.43A d) 1 / RT = 1/ R1 + 1/R2 + 1/R3 1 / RT = 1/240 + 1/280 + 1/300 1 / RT = 2232/21060 21060/2232 = 2232Rt/2232 99 = Rt
99 Rubric for the problem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement Prepared by: MAPHILINDO C. TURARAY EDUARDO C. DELA ROSA Cagayan National High School
100 SCIENCE 8 Name: ________________________________ Section: __________________ Date: _________________________________ Score:____________________ LEARNING ACTIVITY SHEET Advantages and Disadvantages of Series and Parallel Connections Background Information for Learners From your previous lessons about electricity, you have learned that an electrical circuit consists of a load which can be electric bulbs or electrical appliances which consumes electrical power; a voltage source like batteries or generator which supplies electrical energy or a potential difference between two points within an electrical circuit allowing current to be flowing around it; and connecting wires which provides the path for electrons or current to flow. This electrical circuit can be connected either in series or parallel. Series connection has only one path or route for electrons or current to flow, hence, current is the same anywhere in the circuit. For example, if there are three bulbs connected in series, the bulbs will have a lesser brightness since the voltage (measure of strength of electrical power) is shared in ratio to resistance (limits or opposes the flow of electrical current). If one of the bulbs gets busted, the other two bulbs will not work properly or do not produce light since the flow of current is broken or disconnected. Furthermore, as the number of loads are increased in the series circuit, the greater circuit’s resistance is produced. Parallel connection on the other hand, has two or more paths or routes for the flow of current. This explains that the current splits or divides among the loads such as bulbs or appliances. In this case, the voltage across each pathway is the same throughout the circuit. For instance, if there are three bulbs of the same wattage connected in parallel, each bulb produces equal brightness. If one of the bulbs gets busted, the other bulbs will not be affected and still light up because each bulb has a separate connection to a voltage source in the circuit. In other words, if problem may occur in one of the connections in the circuit, other connections will not be affected, hence, current will still pass through in the undisturbed connections. This is the reason why parallel connections are preferred in household wirings because home appliances and other electrical devices operate on the same voltage and that loads or appliances are often switched on and off separately. Learning Competency with code: Explain the advantages and disadvantages of series and parallel connection in homes. (S8FE - Ii - 31)
101 Activity 1: Label Matters I. Directions. Name the two circuits according to the type of connection it represents. Write your answer on the blank below. A B Source: www.physicsclassroom.com ______________________ ________________________ II. Directions: Answer the following questions regarding circuits A and B above. 1. In circuit A, if bulb a burns out, will bulb c still light? _____ Why? __________________ _________________________________________________________________________ 2. In circuit A, if bulbs b and c burn out, will bulb a still light? _____ Why? _____________ _________________________________________________________________________ 3. In circuit B, if bulb d burns out, will bulb f still light? _____ Why? ___________________ _________________________________________________________________________ 4. In circuit B, if bulbs d and f are missing, will bulb e still light? _____ Why? ___________ _________________________________________________________________________ 5. Which do you prefer in your own household electrical wirings, series connection or parallel connection? Why? ___________________________________________________ ___________________________________________________________________________ _______________________________________________________________________ f [ T y p e a q u o t e f r o m t h e d o c u m e n t o r t h e s u m d c f [ f [ T y p e a q u o t e f r o m t h e d o c u m e n t o r t h e e b a
102 Activity 2: Ignite Your Power to Analyze Directions: Study the illustration below and answer the questions that follow. Source: VectorStock.com/20558187 1. If the stand fan is switched off, will the other appliances still continue to work? Why? _________________________________________________________________________ 2. If the stand fan and television are not plugged into an outlet, will the refrigerator function? Why? ____________________________________________________________________ 3. If both the refrigerator and stand fan are unplugged, will the television still work? Why? _________________________________________________________________________ 4. If all appliances are plugged into individual outlets, does it affect the voltage source? Why? ____________________________________________________________________ 5. Appliances at home are usually connected in parallel. What are the advantages of having a parallel connection in household electrical connection? ____________________________ _________________________________________________________________________
103 Activity 3: Glow in the Dark Directions: Analyze the illustrations below and answer the questions that follow. 1. If bulb a is removed from the circuit, will the rest of the bulbs or appliances still work? Why? _________________________________________________________________ 2. What happens to the entire circuit if bulb c get busted? __________________________ ______________________________________________________________________ 3. If two more bulbs are added in the circuit, will the brightness be the same as that of the three bulbs? Why? _______________________________________________________ _______________________________________________________________________ 4. What happens to the entire circuit if the stand fan is damaged? ____________________ _______________________________________________________________________ 5. How are the appliances and electric bulbs connected in the circuit? Is this type of connection possible? Why or why not? ________________________________________ ________________________________________________________________________ ________________________________________________________________________ a b c
104 Activity 4: Explore Your Bright Side Directions: Seek the assistance of your parents to inspect your household electrical connections and answer the following guide questions. 1. Which loads or appliances are connected in series? ____________________________________________________________________ 2. Which loads or appliances are connected in parallel? ____________________________________________________________________ For items 3 and 4, refer to the given situation below: One morning, your mother is ironing your uniform with a stand fan on and a light bulb on. Suddenly, the light bulb sparked and eventually got busted. 3. If the electric iron, stand fan and the bulb are connected in series, can your mother still continue to iron your clothes? Why? _____________________________________ ___________________________________________________________________ 4. If the electric iron, stand fan and the bulb are connected in parallel, can your mother still continue to iron your clothes? Why? ______________________________________ ___________________________________________________________________ 5. What are the advantages and disadvantages of series connection? How about the advantages and disadvantages of parallel connection? Complete the table below. Series Connection Parallel Connection Advantages Disadvantages
105 Activity 5: Spark Your Best Option Directions: Given the situations below, select one of your best choice and work for it. 1. Draw a poster about the advantages and disadvantages of series and parallel connections in homes. 2. Create a two-minute promotional video on the advantages and disadvantages of series and parallel connections in homes. 3. Make a rap song in the form of audio-video about the advantages and disadvantages of series and parallel connections in homes. Rubric for Scoring POSTER MAKING CATEGORY Excellent 4 Good 3 Fair 2 Needs Improvement 1 Graphics - Clarity Graphics are all in focus and the content easily viewed and identified from 6 ft. away. Most graphics are in focus and the content easily viewed and identified from 6 ft. away. Most graphics are in focus and the content is easily viewed and identified from 4 ft. away. Many graphics are not clear or are too small. Graphics - Originality Several of the graphics used on the poster reflect a exceptional degree of student creativity in their creation and/or display. One or two of the graphics used on the poster reflect student creativity in their creation and/or display. The graphics are made by the student, but are based on the designs or ideas of others. No graphics made by the student are included. Graphics - Relevance All graphics are related to the topic and make it easier to understand. All borrowed graphics have a source citation. All graphics are related to the topic and most make it easier to understand. All borrowed graphics have a source citation. All graphics relate to the topic. Most borrowed graphics have a source citation. Graphics do not relate to the topic OR several borrowed graphics do not have a source citation.
106 Labels All items of importance on the poster are clearly labeled with labels that can be read from at least 3 ft. away. Almost all items of importance on the poster are clearly labeled with labels that can be read from at least 3 ft. away. Several items of importance on the poster are clearly labeled with labels that can be read from at least 3 ft. away. Labels are too small to view OR no important items were labeled. Required Elements The poster includes all required elements as well as additional information. All required elements are included on the poster. All but 1 of the required elements are included on the poster. Several required elements were missing. Knowledge Gained Student can accurately answer all questions related to facts in the poster and processes used to create the poster. Student can accurately answer most questions related to facts in the poster and processes used to create the poster. Student can accurately answer about 75% of questions related to facts in the poster and processes used to create the poster. Student appears to have insufficient knowledge about the facts or processes used in the poster. Content - Accuracy At least 7 accurate facts are displayed on the poster. 5-6 accurate facts are displayed on the poster. 3-4 accurate facts are displayed on the poster. Less than 3 accurate facts are displayed on the poster. Attractiveness The poster is exceptionally attractive in terms of design, layout, and neatness. The poster is attractive in terms of design, layout and neatness. The poster is acceptably attractive though it may be a bit messy. The poster is messy or very poorly designed. It is not attractive.
107 VIDEO PRESENTATION Criteria Excellent 4 Good 3 Fair 2 Needs Improvement 1 Content It covers all the topics in depth with details and examples. The knowledge of the topic is excellent. It includes basic knowledge about the topic. The content seems to be good. It includes essential information about the topic but it has 1-2 mistakes in the facts. The content includes minor details and it has several mistakes in the facts. Originality The product shows great originality. The ideas are creative and witty. The product shows certain originality. It shows the use of new ideas and of shrewdness It uses ideas from other people (quoting them0, but there is little evidence of original ideas Uses ideas from other people without quoting them. Use of Language There are no mistakes in spelling or grammar Three or fewer spelling mistakes or punctuation mistakes Four spelling or grammar mistakes More than four spelling or grammar mistakes Videography- Interest A lot of different shots, camera angles, sound effects, and an adequate use of zooming providing variety in the video. Several (3-4) and different shots, camera angles, sound effects, and/or an adequate use of zooming providing variety in the video. One or two different shots, camera angles, sound effects, and/or an adequate use of zooming providing variety in the video. Little effort has been made to provide variety in the video. Videography- Clarity The overall quality of the video and the focus were excellent. Most of the quality of the video and the focus were excellent. The quality of the video is not very good but the overall focus was excellent The quality of the video and the focus are not very good.
108 RAP MUSIC Criteria Excellent Good Fair Accurate All information was accurate in rap There are many inaccuracies You rap’s information was very inaccurate Detailed Your rap was very detailed. I felt like I really knew your person and what he/she stood for Your rap gives some details about your person, but I felt it was lacking some specifics Your rap and visual are too general, I could have made it up just by guessing about the person and how they had great ideas Thorough Your rap and visual covered all essential beliefs and facts about your person Your rap and visual covered a few major points about your person Your rap and visual only covered one main idea. Reflection 4. I have learned that ___________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________. 5. I enjoyed most on ____________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 6. I want to learn more on _______________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
109 References: Bentillo, Eulalia. 2012 Physics, Science and Technology. Quezon City, Philippines. FEP Printing Corporation. Campo, Pia. et.al. 2016. Science Learners Module. Pasig City, Philippines: FEP Printing Corporation. https://www.google.com/search www.physicsclassroom.com https://www.qoura.com/search https://www.google.com/search?q=high+school+rubrics+for+poster&tbm=isch&ved=2ahU KEwib_Y_Rm-_pAhULvJQKHZARBusQ2- https://www.google.com/search?q=high+school+rubrics+for+video+presentation&tbm=isch &ved=2ahUKEwib_Y_Rm_pAhULvJQKHZARBusQ2- https://www.google.com/search?q=high+school+rubrics+for+a+rap+song&tbm=isch&ved= 2ahUKEwjx3u6bzunpAhVD3pQKHWyNBqIQ2cCegQIABAA&oq=high+school+ru brics+for+a+rap+song&gs_lcp=CgNpbWcQAzoCCAA6BggAEAgQHlDDthRYk- YUYL_xFGgBcAB4AIAB
110 Answer Key Activity 1 I. A B Series Parallel II. 1. No, because the flow of current is broken. 2. No, because the flow of current is broken. 3. Yes, because each bulb is individually connected to a voltage source. 4. Yes, because each bulb is individually connected to a voltage source. 5. Parallel, because even if one of the loads is broken, the rest of the loads will not be affected. Activity 2. 1. Yes. Because each appliance has its own path where current flows. 2. Yes. Because electrons or current follow different paths as they flow from negative to positive terminal. 3. Yes. Because it does not affect the paths of the other appliances for current to flow. 4. No. Because all appliances connected in parallel operate with the same voltage source. 5. Parallel connection is preferred over series connection at home for reasons that all appliances operate with the same voltage that is 220V and aside from that, if one of the appliances will be damaged, the other appliances will still function. Unlike in series connection, if one of the appliances will be damaged, the rest of the appliances will no longer work or will no longer function. Activity 3. 1. No. Because the flow of electrons or the flow of current is broken or cut. 2. If bulb c get busted, the rest of the circuit will no longer work. 3. No. Because in series connection, the voltage is shared in ratio to resistance. Hence, the bulbs become dimmer. 4. If the stand fan is damaged, the entire circuit will not function anymore because the path where current flows is disconnected. 5. No. The reason why homes aren’t connected in series is that, the voltage across each appliance will be dropped and so, the last appliance will not get sufficient voltage to drive current and if that happens, some of the appliances will not function well. Aside from that, once you switched off the light during daytime, none of the appliances will
111 work. Subsequently, if lights are switched on during night time, the rest of the appliances will also work and so, unnecessary energy is consumed. Activity 4. 1. The main switch is connected in series with the rest of the loads or appliances at home. 2. Appliances like television, refrigerator, electric fans, electric pot, light bulbs and other electrical appliances are connected in parallel. 3. No. Because the path for current to flow has been disconnected. 4. Yes. Because current can still flow or travel along a different path. 5. Series Connection Parallel Connection Advantages Current flows through every component in the circuit. It is useful when you need to maintain a constant current through each component example in Christmas lights All loads or appliances connected in the circuit gets equal amount of voltage; it does not affect the entire circuit even if one of the loads is being damaged and that current can still pass through the circuit. Disadvantages If you are going to add more output devices, the slower the current becomes and once the circuit is broken, the entire circuit will no longer function It requires a lot of wires in connecting each appliance. There could be a risk of fire in some cases and increasing the number of output devices does not increase the resistance. Prepared by: DIANA D. LACAMBRA Cataggaman National High School
112 SCIENCE 8 Name of Learner: _______________________________ Grade Level:_________________ Section:________________________________________ Date: ______________________ LEARNING ACTIVITY SHEET Electrical Safety Devices Background Information for the Learners Electricity is very essential. It provides us so many valuable things without which life on earth would be difficult. It gives us light and enables us to enjoy some comfort. It also facilitates the performance of certain tasks. But despite its many benefits, electricity could bring danger like the most common house fires and electrocution, which is so fatal. Electrical engineers or electricians often use safety equipment or devices to protect the building as well as the people from injury due to electric shock in the human body. Grounding wires protect people from shocks. If a short circuit occurs in a device, current will go directly into the earth through a low resistance grounding wire. In this way a person who touches the device will be protected. In order to protect people from shocks, electrical systems are grounded. A circuit is electrically grounded when charges are able to flow directly from the circuit into the ground connection in the event of a short circuit. The following are some electrical safety devices (ESD) used in electric circuit that are found in our homes and their functions. 1. Circuit breaker is a safety device that uses an electromagnet that automatically shut off the circuit when there is an excess current from overload or short circuit. It’s easy to reset the circuit breaker. This is done by pulling back a switch after turning off some of the appliances that are causing the high current in the circuit. 2. Fuse is a device that contains a thin strip of metal that will melt if too much current flows through it. It protects the load such as appliances from damaging effects of overcurrent. When the strip of metal melts, or “blows”, it breaks the circuit and stops the flow of current. The electricity might have gone out because a fuse was blown. Once the overload is corrected, the fuse can be replaced and the electricity is restored. When a fuse burns out, it cannot be used again. circuit breaker fuse
113 3. Three-pronged plug. The two flat prongs connect the appliance to the household circuit. This third prong, which is round, connects the metal shell of an appliance to the ground wire of a building. It serves as a ground conductor in order to protect people from electrocution. 4. Lightning rod is a metal rod mounted on the roof of a building in order to protect a building. It is also connected to a grounding wire. When lightning strikes the rod, charges flow through the rod, into the wire and then into the Earth. This protects the building from lightning. 5. Double insulation protects the user of the appliance from an electric shock by preventing any possibility of the external casing becoming live thus, eliminating the need for an earth connection. Some appliances have double insulation, and only need live and neutral wires. They don’t need an earth wire e.g. televisions, computers, printers, and hairdryers. 6. Earthing is the act of connecting the metal casing of the appliance to earth via a wired connection to the bare ground. Earthing wires usually have green and yellow bands around them. It is also a method of transmitting the instant electricity discharge directly to the ground through lower resistance wires or electrical cables. This is one of the significant features of electrical networks. Because it builds the most eagerly accessible and hazardous power source much secure to utilize. Learning Competency with Code: Explain the functions of circuit breakers, fuses, earthing, double insulation and other safety devices in the home. (S8FE-Ii-33) Plug with third prong lightning rod Earthing
114 Activity 1. Let’s Make Connection! Directions: Match the devices in Column B and their respective functions in Column C with the given pictures of items in Column A. Write your Coded answer in the space provided. The first one is done for you. Column A Picture Column B Device name Column C Function Column D Coded answer 1. A. Circuit Breaker I. Connects the metal shell of an appliance to the ground wire of a building 1. C, II 2. B. Double insulation II. Transmits the instant electricity discharge directly to the ground through lower resistance wires or electrical cables 2. 3. C. Earthing III. Protects the building from lighting discharge 3. 4. D. Fuse IV. Shuts off the circuit when the current gets too high using an electromagnet 4. 5. E. Lightning Rod V. Protects the user of the appliance from an electric shock 5. 6. F. Third Prong VI. Melts if too much current flows through it 6.
115 Activity 2. Can You Be My Partner? Directions: Fill in the Venn diagram comparing circuit breaker and a fuse by transferring the sentences below into their appropriate places. Circuit breaker Fuse 1. ______________________ 1. ______________________ _____________________ ______________________ _____________________ ______________________ 2. ____________________ 1. ___________ 2. ______________________ ___________________ ___________ ______________________ ___________________ ___________ ______________________ 2. ___________ ___________ ___________ It looks like switches Protects wiring from overheating It contains a thin strip of metal Uses electromagnet to shut off It burns out and can’t be used again Safety devices that break the circuit whenever overload or short occurs
116 Activity 3. Fact or Bluff? Directions: Write FACT if the statement is correct and write BLUFF if the statement is wrong and give the correct term in the underlined word to correct the statement. Write your answer on the space provided. 1. The human body can be seriously injured by shocks, even those of less than one ampere. ________________________________ 2. Wearing of rubber shoes or slippers when repairing electric appliances is one of the safety measures in handling electricity. ____________________________ 3. Always plug an electrical appliance before attempting to open or repair it. _________________________________ 4. Never replace a blown fuse with coin or just any wire. _________________________ 5. Never overload a circuit by attaching too many appliances to it. __________________ 6. Always replace a blown fuse with a coin or just any wire. _______________________ 7. Don’t ignore switches or outlets that don’t work. Have a qualified electrician check the outlets. ___________________________ 8. Don’t use old extension cords without inspecting them first. ____________________ 9. Don’t switch on electric appliances with wet hands. ___________________________ 10. Pull on the plug, not on the cord to disconnect electrical appliance from the outlet. ________________________ Activity 4. Safety First! Directions: Answer the following questions. 1. What are some important safety devices used in your own homes? Name at least 3 of these electrical devices. ________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. How should you prevent electric shock or electrocution? ______________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. What will happen to fuse if it burns out? ___________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
117 4. Why does connecting too many electrical appliances at the same time in one extension wire with low quality often” blow “ or “burn” a fuse? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Reflection: 1. I learned that ______________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. I enjoyed most on __________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 3. I want to learn more on _____________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ References and Link/s: Acosta, Herma D.et.al. 2015. Science –Grade 10.Learner’s Material. Pasig City. Department of Education . Bentillo, Eulalia N. et .al. 2004. Physics, Science and Technology Textbook for Fourth. Quezon City. Department of Education . Campo, Pia C., et. al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. Holt, Rinehart and Winston, Holt. 2001.Science and Technology, Physical Science. Austin, Texas. A Harcourt Classroom Education Company. Austin, Texas. Padilla, Michael J.et. al. 2001. Focus on Physical Science. Prentice Hall. New Jersey Glenview, Illinois, https://www.gcsescience.com/pe38.htm https://www.thespruce.com/six-ways-of-prevent
118 Answer Key: Activity 1.
1. C, II 2. E, III 3. B, V 4. A, IV 5. F, I 6. D, VI Activity 2. Circuit breaker Fuse 1. It looks like switches ___ 1. It contains a thin strip of _____________________ metal. _____________________ ______________________ 2. Uses electromagnet to 1. Protect wiring 2. It burns out and can’t be used shut off __________from overheating again. ___________________ ___________ ______________________ 2. Safety devices that break the circuit whenever over- load or short occurs Activity 3. 1. Fact 6. Bluff, Never 2. Fact 7. Fact 3. Bluff , Unplug 8. Fact 4. Fact 9. Fact 5. Fact 10. Fact Activity 4. 1. Answers vary (fuse ,circuit breaker, ground conductor ,prong)
2. Possible answers a. Do not “flip”the circuit breaker as ON and OFF switch b. Do not replace the burn fuse without putting down the main switch. c. Never use a coin or piece of metal to replace a burn fuse. d. Do not use old extension wires without inspecting them first. e. Check the extension cord load limit. f. Have a qualified or licensed electrician inspect the circuit breaker, fuse, switches that don’t work anymore. g. Unplug electrical appliances when not in use. 3. The color of the metal wire is black. If a fuse burns out no current will flow and all lights and fixtures along the circuit go dead. It has to be replaced with new one. 4. If too many appliances are connected in a single extension cord this is overloading. Overloading occurs when an electrical wires carries too much current. This may cause the fuse wire to melt or burn because it exceeds the maximum current the household wire can handle. Prepared by: VICTORIA T. IRINGAN Cagayan National High School

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Grade 8 science las

  • 1.
  • 2.
    i Learning Activity Sheetin SCIENCE (Grade 8) Copyright © 2020 DEPARTMENT OF EDUCATION Regional Office No. 02 (Cagayan Valley) Regional Government Center, Carig Sur, Tuguegarao City, 3500 “No copy of this material shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit.” This material has been developed for the implementation of K to 12 Curriculum through the Curriculum and Learning Management Division (CLMD). It can be reproduced for educational purposes and the source must be acknowledged. Derivatives of the work including creating an edited version, an enhancement of supplementary work are permitted provided all original works are acknowledged and the copyright is attributed. No work may be derived from this material for commercial purposes and profit. Republic of the Philippines Department of Education COPYRIGHT PAGE _____________________________________________ Address: Regional Government Center, Carig Sur, Tuguegarao City, 3500 Telephone Nos.: (078) 304-3855; (078) 396-9728 Email Address: region2@deped.gov.ph Website: region2.deped.gov.ph Consultants: Regional Director : ESTELA L. CARIÑO, EdD., CESO IV Assistant Regional Director : RHODA T. RAZON, EdD., CESO V Schools Division Superintendent : REYNANTE Z. CALIGUIRAN, PhD Asst. Schools Division Superintendent : JESUS B. MAGGAY Chief Education Supervisor, CLMD : OCTAVIO V. CABASAG, PhD Chief Education Supervisor, CID : ESTELA S. CABARO, PhD Development Team Writers : ERIC B. PASION, MARIA LORESA J. TUMANGUIL, RIZZA C. BALORAN, SHEELA A. APOSTOL, EDGAR A. SADDUL, GEMMA U. PACAMALAN, REOWIN PALATTAO, VENIE DE LEON, KAREN GACUTAN, MAPHILINDO TURARAY, EDUARDO C. DELA ROSA, DIANA D. LACAMBRA, VICTORIA T. IRINGAN, Cagayan Nat’l HS, Tuguegarao City Science HS Content Editor: EDUARDO C. DELA ROSA, Cagayan National High School ULYSSES DAQUIAOG, Ugad National HS, SDO Isabela Language Editor : MYRNA Q. ADDURU, VISITACION LIGUTAN Illustrators : KATHERINE D. MELAD, TRISHA ELIZABETH J. TUMANGUIL, EMERLITA N. MORALES, VENIE DE LEON Layout Artists : ERIC B. PASION, Cagayan National High School Focal Persons : MYRNA Q. ADDURU, PhD, EPS Science SDO Tuguegarao City JESSICA T. CASTANEDA, PhD, EPS LRMS, SDO Tuguegarao City ESTER T. GRAMAJE, EPS Science-CLMD, DepEd RO2 RIZALINO G. CARONAN, EPS LRMS, DepEd R02 Printed by: DepEd Regional Office No. 02
  • 3.
    ii Table of Contents Competency Page number Investigatethe relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion ..................... 1 Infer that when a body exerts a force on another, an equal amount of force is exerted back on it ..................... 20 Identify and explain the factors that affect potential and kinetic energy ..................... 33 Investigates the effect of temperature to the speed of sound ..................... 45 Explain the hierarchy of colors in relation to the energy of visible light ..................... 57 Differentiate between heat and temperature at the molecular level ..................... 68 Infer the relationship between current and voltage ..................... 78 Explain the advantages and disadvantages of series and parallel connections in homes ..................... 100 Explain the functions of circuit breakers, fuses, earthing, double insulation, and other safety devices in the home ..................... 112
  • 4.
    1 SCIENCE 8 Name ofLearner: ______________________________ Grade Level: _________________ Section: ______________________________________ Date: _______________________ LEARNING ACTIVITY SHEET Force and Motion Background Information for the Learners: In your Grade 7, you described the motion of objects in terms of distance, displacement, speed, velocity, and acceleration. As you remember, distance is the total length of path travelled. Displacement on the other hand is the shortest distance the object makes with respect to the reference point. In other words, distance is measured by virtue of the object’s path, while displacement is measured by virtue of the object’s final position with the point of reference. The time rate at which an object changes distance is speed. Speed tells us how fast the object is going. When the speed of the object is zero, it means that the object is at rest. When the speed of an object has a magnitude equal to any number, it means that the object is moving. The time rate of change in displacement is velocity. Velocity describes how fast the object changes position with respect to the reference point. Zero velocity may mean two things. It may be that the object is at rest or it is moving but is located just right where the reference point is at that instant of time! Just like when you are running around the oval or making a U-turn and returned to the spot where you started. Objects do not usually travel in uniform speed or uniform velocity. This means, velocity changes over time. Objects usually speed up or slow down. Acceleration tells how fast an object changes its velocity. When the acceleration of the object is zero, it means that the object is in equilibrium condition or a state of balance. In other words, the object may not be moving (static equilibrium), or the object is moving at constant velocity (dynamic equilibrium). When this equilibrium condition is disturbed, the object’s state motion is also disrupted. An object that is initially at rest may now begin to move. Similarly, an object that is initially moving at constant speed or constant velocity may speed up, may slow down, or may change direction. In other words, the object accelerates. What causes these changes in an object’s motion and how does it affect acceleration? These are the things that we will investigate through this learning activity sheets.
  • 5.
    2 Learning Competency withCode: Investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion. (Quarter 1, Week 1, S8FE-Ia-15) Activity 1. Loop-a-Word Directions: There are 15 words related to motion which are hidden in the box below. Locate and encircle them. M E R N N I W J F W G N E W T O N Q U E A I F O R C E K H E M S C K H V D W A R G R O S D G I C U I N T E A C T I O N J N A P K F S G M T G U A M L Z X C E G B I F U J N U T Y N H V S Y Q F K M S V T T M L R D X H Q I T W J N M U L A L O E U C L S I Z U K I X K V A I Z J S D X N D G P Y W O G H V T E Q W W A Y S H N S E F B N O R M A L G G U R T S D G P Q I H V K V G C C R B B W F K M B I M T W O I E M G E K U I L I B R O U M R N X V N R C R S W K F S X U V P L X V E N P O I Q T I N E R T I A N G S L M W C P A J F B O P M J Y R L E H K J E N I T L H H R M R E H L A I Z T A L H O L J I Y H E I T Q F X T P D G R K Q S B X L O G M D C Y W A C C E L E R A T I O N P N E D F T R N M J Z Q D S N Z J F R S C B F I A I L I N E O F A C T I O N D W O C Z U Z O T C U W H V D Y J X Q I B P U S H S J N
  • 6.
    3 Force is any__ __ __ __ __ __ __ __ __ __ __ that causes change in an object’s motion. It is caused by either __ __ __ __ or__ __ __ __. Force is a vector quantity with three characteristics. These are line of action, __ __ __ __ __ __ __ __ __, and __ __ __ __ __ __ __ __ __. The SI unit of force is the __ __ __ __ __ __. It is denoted in symbol by capital letter __. It is defined as the amount of force that causes a one-kilogram mass object an acceleration of one meter per second squared in the direction of the force. The expanded form of this unit is __ __ ▪ __ / __ 2 . Activity 2. What can Force Do? Directions: Have you experienced playing football or have you ever watched a football game? Study the picture below and answer the questions that follow. 1. In a football game, what is exerted on the ball as the player kicks it? _____________________________________________________________________ 2. If the football is initially at rest, what happens to its speed as the player kicks it? _____________________________________________________________________ 3. While the football is rolling on the ground, does the surface of the ground offer an opposite force on the ball? _______________________________________________ 4. What is this force exerted by the ground surface on the ball? _____________________________________________________________________ 5. What is the effect of this force to the football’s speed? _____________________________________________________________________ 6. How about when another player blocks a flying football. Does the player exert a force on the ball? ___________________________________________________________ 7. What is the effect of this blocking force to the football’s speed? _____________________________________________________________________ 8. What is the effect of this force to the football’s direction of travel? _____________________________________________________________________ Activity 3. Complete the Message Directions: Fill in the spaces to complete all the statements inside the box. Each space corresponds to a letter.
  • 7.
    4 Activity 4. BalancedForce Normally, there are more than one forces acting on an object. When two or more forces act on an object, they add up algebraically to get the combined effect of the forces called Resultant Force or Net Force. Directions: A free-body diagram (FBD) illustrates the forces acting on an object to determine the resultant force. Interpret the free-body diagrams below and answer the questions that follow. A. Tension A pendulum is suspended at a certain height. The string exerts tension on the bob with a force of 0.01 N. The weight of the bob is also 0.01 N. String Tension = 0.01 N Pendulum bob Weight = 0.01 N 1. What are the two forces acting on the bob? __________________________________ 2. What is the direction of each force? ________________________________________ 3. Using the Cartesian coordinate plane (x-y coordinate plane) what is the sign of an upward force? _________________________________________________________ 4. Using the Cartesian coordinate plane (x-y coordinate plane) what is the sign of a downward force? ______________________________________________________ 5. With positive and negative signs affixed with the upward and downward forces, respectively, add the two forces together. F net = F1 + F2 _________________________________________________________________________________________ 6. If the Fnet on the pendulum is equal to zero, will the bob swing sideways? __________ 7. If the Fnet on the pendulum is equal to zero, will the bob move upward? ___________ 8. If the Fnet on the pendulum is equal to zero, will the bob move downward? _________ 9. Are the two forces acting on the pendulum balanced? __________________________ 10. What is the Fnet when forces are balanced? __________________________________
  • 8.
    5 B. Normal A boxweighing 20 N is placed on top of a table. The table supports the weight of the box with an upward normal force of 20 N. Box Normal = 20 N Table Weight = 20 N 1. What are the two forces acting on the box? __________________________________ 2. What is the direction of each force? ________________________________________ 3. Which force takes a positive sign? _________________________________________ 4. Which force takes a negative sign? ________________________________________ 5. With positive and negative signs affixed with the upward and downward forces, respectively, add the two forces together. F net = F1 + F2 ___________________________________________________________________ 6. If the Fnet is equal to zero, will the box slide sideways? ________________________ 7. Are the two forces acting on the box balanced? ______________________________ 8. What makes the forces balanced? Describe their magnitude and direction. _____________________________________________________________________ _________________________________________________________________ C. Friction A load is pushed to the right along a horizontal floor with a force of 50 N. Static friction acts towards the opposite direction with a frictional force of 50 N. Load Static Friction = 50 N F1= 50 N Floor 1. What is the net force or resultant force, Fnet? ___________________________ 2. Are the two forces acting on the load balanced? ________________________ 3. Will the box move because of balanced forces? ________________________ Balanced forces on objects that are initially at rest illustrate the first fragment of Newton’s First Law of Motion or the Law of Inertia. Complete the statement of the Law of Inertia for objects that are initially at rest. Write the correct group of words on the blank.. When forces are balanced, objects at rest will _________________.
  • 9.
    6 Activity5. Unbalanced Force Directions:Read and analyze the given situations and the free-body diagrams below. Answer the questions that follow. A. A load initially at rest is pushed to the right along a horizontal floor with a force of 50 N. Starting friction acts towards the opposite direction with a frictional force of 20 N. Load Starting Friction = 20 N F1= 50 N Floor 1. What is the magnitude of the resultant force or Fnet? ___________________________ 2. What is the direction of the net force? ______________________________________ 3. Are the forces balanced? ________________________________________________ 4. Will the load move? ____________________________________________________ 5. In what direction will the load move? ______________________________________ B. A boy pushes a toy car at the back with a force of 2 N, to the right. Another boy applies a force of 3 N to the right by pulling a string attached in front of the toy. The sliding friction is 2 N to the left. Toy car F1 = 2 N Friction = 2N F2 = 3 N Floor 1. What is the magnitude of the resultant or net force? _____________________ 2. What is the direction of the resultant force? ____________________________ 3. Will the toy car move? In what direction will it go?______________________ _______________________________________________________________
  • 10.
    7 Objects at restwill remain at rest. Objects in motion will continue to __ __ __ __ in a __ __ __ __ __ __ __ __ line path with a __ __ __ __ __ __ __ __ speed, unless acted upon by a net force or __ __ __ __ __ __ __ __ __ __ force. C. A ball rolling along a horizontal floor in a straight line path with a constant velocity of 2 m/s is kicked with a force of 5 N to the right. Rolling friction between the surfaces of the ball and the ground is 2.5 N Ball F1 = 5 N Floor Friction = 2N 1. What is the magnitude of the net, resultant force? _______________________ 2. What is the direction of the net, resultant force? ________________________ 3. What is the velocity of the ball before it was kicked? ____________________ 4. What is constant velocity? Does it speed up, slow down, or remain the same? _______________________________________________________________ 5. What is expected to happen to the speed of the ball after the kick? _______________________________________________________________ 6. What causes any change in the state of motion of the ball? _______________________________________________________________ Complete the statement of Newton’s First Law of Motion or the Law of Inertia.
  • 11.
    8 Activity 6. Effectof Force to Acceleration Directions: Investigate how different amounts of force affect the object’s acceleration differently by examining the given situations below. Answer the questions that follow. A. Two wooden carts below having the same mass of 2 kilograms are lying on a frictionless horizontal floor. The first cart is pushed with a force of 2 N to the right, while the second cart is pushed with a force of 4 N to the right. Cart 1 Fnet = 2 N Frictionless Floor Cart 2 Fnet = 4 N Frictionless Floor 1. What is the effect of Fnet on both carts? _____________________________________ 2. Which of the two carts will gain greater velocity? _____________________________ 3. Which of the two carts will accelerate faster? ________________________________ 4. How many times faster will one cart accelerate compared to the other? ____________ 5. What happens to the acceleration of the cart when the force applied to it is doubled? _____________________________________________________________________ B. Another cart is now placed on the same floor. Cart 3 has the same mass of 2 kilograms with Cart 1 and Cart 2. A force of 8 N to the right is exerted to it. Compare the effect of this force with the first two carts. Answer the questions that follow. Cart 3 Fnet = 8 N Frictionless Floor 1. How much greater is the net force on cart 3 compared to cart 1? _________________ 2. How much faster will cart 3 accelerate, compared to cart 1? ____________________ 3. How much greater is the net force of cart 3 compared to cart 2? _________________ 4. How much faster will cart 3 accelerate, compared to cart 2? ____________________ 5. When net force is increased, what happens to the acceleration? __________________ 6. What is the relationship of net force and acceleration? _________________________ ____________________________________________________________________
  • 12.
    9 Acceleration is (directly,inversely) proportional to net force. This means that increasing the net external force applied to an object will (decrease, increase) the object’s acceleration. When force is doubled, acceleration is (doubled, halved).When force is decreased four times, acceleration (increases four times, decreases four times). At this point you should be able to state the effect of net force to the acceleration of an object. This is the first fragment of the statement of Newton’s Second Law of Motion or the Law of Acceleration! Encircle the correct term enclosed in the parenthesis to complete each statement in the box below.
  • 13.
    10 Activity 7. Effectof Mass to Acceleration Directions: Investigate the effect of mass to an object’s acceleration by examining the given situations below. Answer the questions that follow. A. Two wooden carts lying on a frictionless horizontal floor are pushed with equal amount of force of 10 N to the right. The first cart has a mass of 5 kg, while the second cart has a mass of 10 kg. Cart 1 mass = 5 kg Fnet = 10 N Frictionless Floor Cart 2 mass = 10 kg Fnet = 10 N Frictionless Floor 1. Which of the two carts will gain greater acceleration? _________________________ 2. How many times the acceleration of one cart as compared to the other cart be? _____________________________________________________________________ 3. What affects the difference in the acceleration of the two carts? __________________ 4. What happens to the acceleration of the cart when the mass is doubled? _____________________________________________________________________
  • 14.
    11 Acceleration is (directly,inversely) proportional to mass. This means that increasing the mass of an object will (decrease, increase) the object’s acceleration. When mass is doubled, acceleration is (doubled, halved). When mass is decreased four times, acceleration (increases four times, decreases four times). B. Another cart is placed on the same floor as shown below. The same amount of force as Cart 1 and Cart 2 is applied to Cart 3. The mass of Cart 3 is 20 kilograms. Compare the effect of this mass to acceleration with the other carts. Answer the questions that follow. Cart 3 mass = 20 kg Fnet = 10 N Frictionless Floor 1. How much greater is the mass of cart 3 as compared to cart 1? __________________ 2. How much slower will cart 3 accelerate as compared to cart 1? _________________ 3. How much greater is the mass of cart 3 as compared to cart 2? __________________ 4. How much slower will cart 3 accelerate as compared to cart 2? _________________ 5. When the mass of the object is increased, what happens to its acceleration? _____________________________________________________________________ At this point you should be able to state the effect of mass to the acceleration of an object. This is the second fragment of the statement of Newton’s Second Law of Motion or the Law of Acceleration! Encircle the correct term enclosed in the parenthesis to complete each statement in the box below.
  • 15.
    12 Activity 8. ApplyingNewton’s Second Law of Motion Newton’s second law of motion or the Law of Acceleration can be summarized by the equation: Where: is the acceleration of the object in m/s2 ; is the net external force in newtons (N) ; and, m is the mass of the object in kilograms (kg). Directions: Apply this formula in solving the following problems. Show your complete solution. 1. A 5 kg object is pushed along a frictionless floor with a force of 3 N. What is the acceleration of the object? 2. How much force is needed to cause a 2 kilogram object with an acceleration of 6 m/s2 ? 3. What is the mass of an object accelerated at 4 m/s2 by a force of 20 N? 4. A cart with a mass of 8 kilograms is pulled along a horizontal rough surface with a force of 56 N. The floor offers a rolling friction of 16 N on the wheels of the cart. What is the acceleration of the cart? Cart mass = 8 kg F1 = 56 N Rough Surface Rolling Friction = 16 N
  • 16.
    13 Activity 9. Summingit Up! Directions: With activities 1 to 8, you were able to investigate the relationship between the amount of force applied and the mass of the object to the amount of change in the object’s motion. In other words you described the motion of an object in terms of the factors causing such change in motion. To help you generalize your lesson, answer briefly the questions that follow. 1. In terms of motion, what can net external force do to an object? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. How does net external force affect the object’s acceleration? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 3. How does the object’s mass affect its acceleration? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Reflection: 1. I learned that __________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 2. I enjoyed most on _______________________________________________________ ________________________________________________________________________ ________________________________________________________________________ 3. I want to learn more on ____________________________________________________ ________________________________________________________________________ ________________________________________________________________________
  • 17.
    14 References: Campo, Pia C.,et. al. 2003..Science – Grade 8. Learner’s Module. Pasig City. Department of Education. - Cordero-Navaza, Delia & Bienvenido J. Valdes. 1996. You and the Natural World Series: Physics. Quezon City, Philippines. Phoenix Publishing House Inc., Padua, Alicia L., et.al. 2003. Practical and Explorational Physics, Modular Approach. Quezon City, Philippines. Vibal Publishing House, Inc., Salmorin, Lolita M. & Alberto V. Florido Jr. 2009. Science and Technology IV-Physics. Quezon City, Philippines. Abiva Publishing House Inc., Silverio, Angelina A. & Rosemarie S. Cabauatan. 2006. Exploring Life Through Science. Physics. Teachers Guide. Quezon City, Philippines. Phoenix Publishing House, Inc., Young & Freedman. 2004. Sear’s and Zemansky’s University Physics with Modern Physics.11th Edition. San Francisco, California, USA. Pearson Education Inc.,
  • 18.
    15 Answer Key Activity 1. ME R N N I W J F W G N E W T O N Q U E A I F O R C E K H E M S C K H V D W A R G R O S D G I C U I N T E A C T I O N J N A P K F S G M T G U A M L Z X C E G B I F U J N U T Y N H V S Y Q F K M S V T T M L R D X H Q I T W J N M U L A L O E U C L S I Z U K I X K V A I Z J S D X N D G P Y W O G H V T E Q W W A Y S H N S E F B N O R M A L G G U R T S D G P Q I H V K V G C C R B B W F K M B I M T W O I E M G E K U I L I B R O U M R N X V N R C R S W K F S X U V P L X V E N P O I Q T I N E R T I A N G S L M W C P A J F B O P M J Y R L E H K J E N I T L H H R M R E H L A I Z T A L H O L J I Y H E I T Q F X T P D G R K Q S B X L O G M D C Y W A C C E L E R A T I O N P N E D F T R N M J Z Q D S N Z J F R S C B F I A I L I N E O F A C T I O N D W O C Z U Z O T C U W H V D Y J X Q I B P U S H S J N Activity 2. 1. Force 2. Speeds up or increases 3. Yes 4. Friction 5. It slows down the ball. 6. Yes 7. The ball may stop or bounce with a faster / slower speed (answers may vary) 8. The ball changes direction
  • 19.
    16 Activity 3. Force isany INTERACTION that causes change in an object’s motion. It is caused by either PUSHor PULL Force is a vector quantity with three characteristics. These are line of action, MAGNITUDE and DIRECTION. The SI unit of force is the NEWTON. It is denoted in symbol by capital letter N. It is defined as the amount of force that causes a one-kilogram mass object an acceleration of one meter per second squared in the direction of the force. The expanded form of this unit is kg▪m/s2 . Activity 4. A. Tension 1. Weight and Tension 2. Upward for tension, downward for weight 3. Positive 4. Negative 5. F net = F1 + F2= 0 Newton 6. No 7. No 8. No 9. Yes 10. Fnet= 0 N B. Normal 1. Normal and Weight 2. Upward for normal, downward for weight 3. Normal 4. Weight 5. F net = F1 + F2= 0 N 6. No 7. Yes 8. Forces are balanced when their F net is zero. Two forces are balanced when they are equal in magnitude but opposite in direction (* Teacher must emphasize that the forces must act on the same object) C. Friction 1. Fnet = 0 2. Yes 3. No
  • 20.
    17 Complete the statementbelow. When forces are balanced, objects at rest will remain at rest. Activity 5. A. 1. Fnet = 30 N 2. To the right 3. No 4. Yes 5. To the right B. 1. 3 N 2. To the right 3. Yes.To the right C. 1. 3 N 2. To the right 3. Constant 2 m/s 4. Velocity/ speed remains the same 5. The ball will gain speed 6. Unbalanced force or net force Objects at rest will remain at rest. Objects in motion will continue to MOVE in a STRAIGHT line path with a CONSTANT speed, unless acted upon by a net force or UNBALANCED force. Activity 6. A. 1. Net force causes both carts to move 2. Cart 2 3. Cart 2 4. Cart 2 will accelerate 2x greater than Cart 1 5. The acceleration of the cart also doubles.
  • 21.
    18 B. 1. Force oncart 3 is 4x greater than that of cart 1? 2. 4x faster 3. 2x greater 4. 2x faster 5. Acceleration also increases 6. Direct relationship/ acceleration increases with force Encircle the correct term enclosed in the parenthesis to complete each statement in the tale below. Acceleration is (directly, inversely) proportional to net force. This means that increasing the net external force applied to an object will (decrease, increase) the object’s acceleration. When force is doubled, acceleration is (doubled, halved). When force is decreased four times, acceleration (increases four times, decreases four times). Activity 7. A. 1. Cart 1 2. Cart 1 will gain twice as great as the acceleration of Cart 2. 3. Mass 4. Acceleration is halved B. 1. 4x greater 2. 4x slower 3. 2x greater 4. 2x slower 5. Acceleration decreases Encircle the correct term enclosed in the parenthesis to complete each statement in the box below. Acceleration is (directly, inversely) proportional to mass. This means that increasing the mass an object will (decrease, increase) the object’s acceleration. When mass is doubled, acceleration is (doubled, halved). When mass is decreased four times, acceleration (increases four times, decreases four times).
  • 22.
    19 Activity 8. 1. 0.6m/s2 2. 12 N 3. 5 kg 4. 5m/s2 Activity 9 1. A net force causes an object to move, stop, slow down, speed up, and/or change direction. Net force causes acceleration. 2. Net external force directly affects the object’s acceleration. When Fnet is increased, acceleration increases. 3. Mass inversely affects acceleration. When mass is increased, acceleration decreases. Prepared by: ERIC B. PASION Cagayan National High School
  • 23.
    20 SCIENCE 8 Name ofLearner: ______________________ Grade Level:_______________ Section: ______________________________ Date:_____________________ LEARNING ACTIVITY SHEET Newton’s Third Law of Motion Background Information for the Learners: Read the selection below: What is the moral of the story? If you encountered a situation similar to helping a certain person, would you also extend your service without hesitation? Take note of what the comic strip is saying. Do you want to understand why this is happening? Scientifically, one’s action and its reaction is explained by the force around us. A force is always part of a mutual action that involves another force. Basically, force is a push or a pull. A mutual action is an interaction between one thing and another. Why do forces always occur in pairs? Newton’s third law of motion states that whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object. Paramedic Mike Sibal was born ten weeks early and in need of a trustworthy doctor. His parents found Jose Rapatan, MD, a pediatrician who stayed with the baby for two nights after he came down with a life-threateningly high fever. Thirty years later and all grown up, Sibal, a paramedic, was called in to help at the site of a car wreck. The car was on fire with a man still stuck inside. After firefighters helped put out the flames and Jaws of Life opened the car, Sibal brought the injured man into an ambulance. He learned the rescued victim’s name was Jose Rapatan—the very same Jose Rapatan who’d saved his life as a baby.
  • 24.
    21 Newton’s third lawdescribes the relationship between two forces in an interaction which has the following properties: Identifying Action and Reaction When action A exerts force on B, the reaction is simply B exerts a force on A. Look at the examples in the following figures. REACTION Action: Tire pushes the road Reaction: The road pushes the tire REACTION ACTION C T I O N Action: The tower exerts a weight on the earth Reaction: The earth exerts a normal force to support the tower REACTION ACTION
  • 25.
    22 DID YOU KNOW? Understandinghow a helicopter gets its lifting force Competency (Code): Infer that when a body exerts a force on another, an equal amount of force is exerted back on it (S8FE-Ia-16) ACTIVITY 1. What’s Your Action and Reaction? Directions: Identify from the situation the ACTION and its corresponding REACTION. Write down the Action and the Reaction Forces on the space provided on the right side of each illustration. To identify a pair of action-reaction forces, first identify the interacting objects A and B, and if the action is A on B, the reaction is B on A. There is a simple recipe for treating action and reaction forces: First identify the interaction. Let’s say one object, A, interacts with another object, B. Second, the action and reaction forces are stated in the form: Action: Object A exerts a force on object B. Reaction: Object B exerts a force on object A. 1. A bird while flying pushes the air downwards with the help of its wings. The air pushes the bird upwards for lift.
  • 26.
    23 2. A manis propelled upward and then down into the swimming pool as he jumps on the diving board. He exerts a downward force on the diving board and the diving board simultaneously exerts an equal force on the man but in the upward direction. 3. Walking is possible- as you walk, you exert a force against the floor (down and backward) and the floor exerts a force back (up and forward), causing you to move forward. 4. 5. A fireman has to hold on tightly to a fire hose. The hose will fly backwards as water shoots out from it. The swimmer pushes against the water while the water pushes back on the swimmer and pushes her forward.
  • 27.
    24 Activity 2. TheDirection of Your Reaction Directions. Consider the following figure. Draw a counterpart arrow that illustrates the direction of the reaction force. 1. Action: Head bumps ball. Reaction:____________ 6. Action: Hand pulls on flower Reaction:____________ 2. Action: Windshield hits bug Reaction:____________ 7. Action: Athlete pushes barbell upward Reaction:____________ 3. Action: Fist hits wall Reaction:____________ 8. Action: Compressed air pushes balloon surface upward Reaction:____________ 4 Action: Hand touches nose Reaction:____________ 9. Action: Air rushes down Reaction:____________ 5. Action: Bat hits ball Reaction:____________ 10. Action: Foot pushes down Reaction:____________
  • 28.
    25 Activity 3. Puzzledwith Forces Directions. Fill in the crossword puzzle with the words missing from the sentences below. Match the number of the sentence to the boxes placed across or down the grid. 1 2 3 4 5 6 7 8 9 10 Across 3. Force acting on one direction 4. A man shoots a rifle and the force of the shot results in recoil. The magnitude of the force on the rifle __________ the magnitude of force on the bullet. 9. The force that acts on an object to stop its motion 10. Reaction always go in the _______ direction of the action Down 1. The force that pull things toward Earth 2. A book exerts a force of 2N downwards, into a chair that exerts a force of 5N downwards to the floor it stands on. What is the force that the floor exerts upwards on the chair? 5. For every action there is an equal and opposite reaction 6. Force acting on the opposite direction 7. Forces always come in _____. 8. A push or a pull
  • 29.
    26 Activity 4. Forceof Choices Directions: Choose the answer from the given questions. Encircle the letter of the correct answer. 1. What could correctly complete the following statement? “A force interaction requires at least a(n)________________” A.Action force. B. Pair of force. C. Reaction force. D.Single force. 2. What wouldcorrectly fill the following statement? “Whenever one subject exerts a force on a second object, the second object exerts a force on the first that is__________” A.in the same direction and equal in magnitude at the same time. B. in the same direction and lesser in magnitude at the same time C. opposite in direction and equal in magnitude at the same time. D.opposite in direction and greater in magnitude at the same time 3. What object will provide a forward motion force to a motor scooter along a higway which is a reaction from the vehicle’s tires? A.Engine B. Fuel C. Road D. Steering Wheel 4. What is the direction of gravity against a person when he jumps from the ground? A.Downward B. Upward C. To the left D. To the right 5. What will happen if a net force acts on a horse while pulling a wagon? A.The horse-wagon system accelerates. B. The horse-wagon system does not move. C. The horse-wagon system is pulled backwards. D.The horse will accelerate but the wagon will be steady. 6. At a pizza shop, the cook throws the pizza dough in the air. On what factor will the amount of force that the cook exerts on the dough depend on? A.Brand label of the dough C. Mass of the dough B. Color of the dough D. Strength of the dough 7. While driving down the road, a firefly strikes the windshield of a bus and makes a quite obvious mess in front of the face of the driver. The firefly hit the bus and the bus hits the firefly. Which of the following statements is correct? A.The force of the firefly on the windshield is zero. B. The force of the firefly is lesser than the force of the bus. C. The force of the firefly is greater than the force of the bus. D.The force of the firefly and the bus have no difference in magnitude. 8. Which of the following situation best describes Newton’s Third Law of Motion? A. A rifle recoils when fired. B. Occurrence of high and low tides. C. A follow through is needed when a golfer hits the ball with a golf club. D. A chocolate vendor has to move with the bus as he jumps off the bus. 9. Trisha, who has a mass of 30 kg stands on platform. What is the magnitude of force called Normal Force does the platform exert on Trisha? A. 9.8 N C. 257.5 N B. 30.00 N D. 294.00 N
  • 30.
    27 10. Two 100-Nweights are attached to a scale called spring balance as shown. What is the reading on the scale? A. 0 N B. 50 N C. 150 N D.200 N Activity 5- Decode the Forces in Your Life Life is a matter of decoding the forces around us. If you push hard on the world, the world pushes hard on you. If you touch the world gently, the world would touch you gently in return. Since you have mastered what the Newton’s Third Law of Motion says, it is now time to apply it to real life situations. Directions: Decrypt the following cryptograms. The titles are the clues of the phrases that you need to crack. These phrases are quotes which exhibits life’s action-reaction forces. Enjoy decoding! 1. Gaps, stimulus and reactions
  • 31.
    28 2. Spiritual Reactionof a person 3. Emotional forces 4. To accept or to surrender
  • 32.
    29 5. Self-Realization Reflection: In thethird law of motion, if there is an action, there will be a reaction. In real-life situations, good deeds can yield the same. Thus, be reminded of the golden rule: do unto others what you want others to do unto you (Arevalo, R., 2017) 1. I learned that _______________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ 2. I enjoyed most on ___________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ 3. I want to learn more on _______________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________
  • 33.
    30 References: “Action = Reaction.”8TH GRADE SCIENCE. Accessed June 3, 2020. https://clarkscience8.weebly.com/action--reaction.html. Arevalo, Ryan L. Diwa Senior High School Series . Makati City, Philippines: Diwa Learning Systems Inc, 2017 “Comic Strip Starters: MakeBeliefxComix.com.” Make Beliefs Comix, September 15, 2019. https://www.makebeliefscomix.com/original-comic-strip-starters/. Google Search. Google. Accessed June 3, 2020. https://www.google.com/search?q=action and reaction quotes life&tbm=isch&source=iu&ictx=1&fir=mOsjoI2- TQZ68M:,4rj3NU2i9_Ou3M,_&vet=1&usg=AI4_- kS_b0khIiQMlHNWktiVifEdKKFf_w&sa=X&ved=2ahUKEwju3428lt3pAhWpwos BHRVkB7EQ9QEwB3oECAoQIg#imgrc=mOsjoI2-TQZ68M: Hewitt, Paul G. Conceptual Physics. Boston: Pearson, 2015. Padua, Alicia L, and Ricardo M Crisostomo. Practical and Ecxplorational Physics Modular Approach. Edited by Lilia M Rabago. Vibal Publishing House, Inc., 2003 “Reaction Sayings and Quotes.” Reaction Sayings and Reaction Quotes | Wise Old Sayings. Accessed May 27, 2020. https://www.wiseoldsayings.com/reaction-quotes/. “The Law of Action-Reaction (Revisited).” The Physics Classroom. Accessed May 28, 2020. https://www.physicsclassroom.com/class/momentum/Lesson-2/The-Law-of-Action- Reaction-(Revisited). “TOP 25 ACTION AND REACTION QUOTES: A-Z Quotes.” A. Accessed June 3, 2020. https://www.azquotes.com/quotes/topics/action-and-reaction.html. “Welcome to Discovery Education's Puzzlemaker! Create Crossword Puzzles, Word Searches, Mazes, and Other Puzzles for Your Classroom Today!” Welcome to Discovery Education's Puzzlemaker! Create crossword puzzles, word searches, mazes, and other puzzles for your classroom today! Accessed June 3, 2020. http://puzzlemaker.discoveryeducation.com/. Answer Key: Activity 1 1. Action: A bird wings pushes the air downwards. Reaction: The air pushes the bird upwards for lift. 2. Action: The man exerts a downward force on the diving board. Reaction: The diving board simultaneously exerts an equal force on the man but in the upward direction. 3. Action: A person exerts a force against the floor (down and backward).
  • 34.
    31 Reaction: The floorexerts a force back (up and forward), causing you to move forward. 4. Action: A fireman has to hold on tightly to a fire hose Reaction: The hose will fly backwards as water shoots out from it. 5. Action: The swimmer pushes against the water Reaction: The water pushes back on the swimmer and pushes him forward. Activity 2 1. Action: Head bumps ball. Reaction: Ball bumps head 6. Action: Hand pulls on flower Reaction: Flower pulls on hand 2. Action: Windshield hits bug Reaction: Bug hits windshield 7. Action: Athlete pushes barbell upward Reaction: Barbell pushes down 3. Action: Fist hits wall Reaction: Wall hits fist 8. Action: Compressed air pushes balloon surface outward Reaction Balloon surface pushes ________ compressed air inward ___ 4 Action: Finger touches nose Reaction: Nose touches finger 9 Action: Air rushes down Reaction: Balloon goes up 5. Action: Bat hits ball Reaction: Ball hits bat 10. Action: Foot pushes down Reaction: Floor pushes up
  • 35.
    32 Activity 4 1. B 2.C 3. C 4. A 5. A 6. C 7. D 8. A 9. C 10. A Activity 5 1. Create gaps between stimulus and reaction and the gap will show you the path by Amit Ray 2. God’s reaction towards things is different from ours and He wishes that our reaction will line up with His by Sunday Adelaja 3. How you react emotionally is a choice in any situation. by Judith Orloff 4. Acceptance is an active response to a temporary situation; surrender is a passive reaction to a situation that you think will last forever by Oli Anderson 5. If a man realizes who he is, he will not react to the negative things surrounding him by Sunday Adelaja. Prepared by: RIZZA C. BALORAN MARIA LORESA J. TUMANGUIL Tuguegarao City Science High School Illustrator: TRISHA ELIZABETH J. TUMANGUIL
  • 36.
    33 SCIENCE 8 Name ofLearner: ______________________ Grade Level: _______________ Section: ______________________________ Date: _____________________ LEARNING ACTIVITY SHEET Potential Energy and Kinetic Energy Background Information for the Learners: Read the comic strips.
  • 37.
  • 38.
    35 Potential energy= weightx height (P.E =w x h) Note: Since weight=mass x acceleration due to gravity, P.E can be written also as (P.E =m x g x h) The units used are: Energy =Joules, J Weight= Newtons, N Height= meters, m Mass= Kilograms, kg Acceleration due to gravity= (9.8 m/s2 ) Activity 1: How Potential am I? Directions: Study table A and table B below and analyze the different quantities given. Then, answer the questions that follow. Table A: PE of the object when the mass varies while the height remains the same Table B: PE of the object when the mass remains the same as height increases 1: In table A, what happens to the P.E of the object when mass increases but the height of the object remains the same? ___________________________________________________________________________ 2: In table B, what happens to the P.E of the object when height increases but the mass of the object remains the same? ___________________________________________________________________________ 3: What are the factors that affect the P.E of an object? ___________________________________________________________________________ Mass, kg Acceleration due to gravity, m/s2 Height, m P.E (P.E=mgh), J 1 9.8 2 19.6 2 9.8 2 39.2 3 9.8 2 58.8 Mass, kg Acceleration due to gravity, m/s2 Height, m P.E (P.E=mgh), J 2 9.8 1 19.6 2 9.8 2 39.2 2 9.8 3 58.8
  • 39.
    36 4: How canmass/weight and height affect the P.E of an object? ___________________________________________________________________________ 5: What is the relationship of mass/weight and height to the P.E of an object? ___________________________________________________________________________ 6: Give at least two (2) situations where we can apply P.E in our real life. ___________________________________________________________________________ ___________________________________________________________________________
  • 40.
    37 Kinetic energy= ½mass x velocity2 In symbol: (K.E=1/2 mv2 ) The units used are: Mass (m) = kilograms, kg (Velocity)2 (v2 ) = meter2 /second2 , m2 /s2 Activity 2: Kick Here! Kick There! KINETIC Anywhere! Directions: Study table C and D below and analyze the different quantities given. Then, answer the questions that follow. Table C: KE of the object when the mass increases and the square of its velocity remains the same Table D: KE of the object when the mass remains the same while the square of its velocity increases 1. In table A, what happens to the K.E of the object when mass increases but the velocity of the object remains the same? ______________________________________________________________________ 2. In table B, what happens to the K.E of the object when the velocity doubles but the mass of the object remains the same? ______________________________________________________________________ 3. What happens to the K.E of an object when the object is massless? When velocity is zero? What can you infer in this situation? ______________________________________________________________________ ______________________________________________________________________ Mass, kg (Velocity)2 , m2 /s2 K.E (K.E=1/2 mv2 ), J 0 2 0 1 2 2 2 2 4 Mass, kg (Velocity)2 , m2 /s2 K.E (K.E=1/2 mv2 ), J 2 0 0 2 2 4 2 4 16
  • 41.
    38 4. What arethe factors that affect the K.E of an object? ______________________________________________________________________ 5. How can mass and velocity affect the K.E of an object? ______________________________________________________________________ 6. What is the relationship of mass and velocity to the K.E of an object? ______________________________________________________________________ 7. Give at least two (2) applications/situations where we can apply K.E in our real life. ______________________________________________________________________ ______________________________________________________________________ Activity 3: Jack and Hill Directions: Identify the relationship between Kinetic Energy and Potential Energy of the cyclist at each position as shown in the illustration below. Choose the letter of your answer from the given choices. Credits: https://www.google.com/search?q=comic+strip+on+potential+and+kinetic+energy+png 1. ___________ 2. ___________ 3. ___________ 4. ___________ 1 2 3 A. K.E increases while P.E decreases. B. P.E is at a minimum. C. K.E decreases while P.E increases. D. P.E is at a maximum.
  • 42.
    39 Activity 4: Gameof Energetics Adapted from: theeducationcenter.com by PINTEREST Directions: In the following competition, Team Potential and Team Kinetic will each try to emerge as the winner. To find out who comes out on top, read the description of each player’s energetic action. Then check the correct box to indicate which team can take credit for the action. When finished, total the scores and show the final results on the scoreboard. ENERGY SCOREBOARD POTENTIAL KINETIC Team Potential Team Kinetic 1. Player 11’s rock is at the top of a hill. 2. Player 22 aims a stretched rubber band at the target. 3. Player 33 shoots her rubber band toward the goal. 4. Player 14 waits, with his bow pulled back, to release the arrow. 4. Player 35 kicks the football. 5. Player 26 hits the golf ball with his club. 6. Player 17 releases the arrow from his bow. 7. Player 48 pushes the rock over the cliff 8. The pitcher stands with his arm above his head and the ball in his hand. 10. Player 50 is holding a 2-kg rock 1.5m above the floor.
  • 43.
    40 Activity 5: PEand KE are PROBLEMatic Directions: Solve the following problems. Show your solution. 1. What is the potential energy of a rock that weighs 150 Newtons that is sitting on top of a hill 200 meters high? 2. A 1500-kg automobile is traveling at a velocity of 120 m/s. How much kinetic energy does it possess? 3. A flower pot has a mass of 8kg on a window 30 meters from the ground. What is the gravitational potential energy of the flower pot in joules? 4. A toy car that weighs 15 kg is rolling down a hill with a velocity of 4.5 m/s. What is the kinetic energy of the toy car? 5. A 25 kg block is raised by a crane 4 meters above the ground. What is the potential energy of the block?
  • 44.
    41 REFLECTION: 1. I learnedthat _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. I enjoyed most on _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. I want to learn more on _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
  • 45.
    42 References: Campo, Pia C.,et.al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. CK12 Foundation. “Potential Energy.” Accessed May, 2020. https://www.ck12.org/c/physics/ potential-energy/lesson/Potential-Energy-PHYS/?referrer=concept_details. Storyboard That. “Digital Storytelling.” Accessed May,2020. https://www.storyboardthat. com/.
  • 46.
    43 Answer Key: Activity #1:How Potential am I? 1. The P.E also increases. 2. The P.E also increases. 3. Mass/Weight and height. 4. If the mass/weight and height increases, the PE also increases. 5. Mass/Weight of an object and its height is directly proportional to the P.E. 6. Sample answers: A yoyo before it is released. The wick in a candle. Fireworks before they are launched Activity #2: Kick here! Kick There! KINETIC anywhere! 1. If the mass is 0, the K.E is also zero. If the mass increases, the K.E also increases. If the mass doubles, the K.E also doubles. 2. If the velocity is 0, the K.E is also zero. If the velocity increases, the K.E also increases. If the velocity doubles, the K.E increases by a factor of four. That is because velocity is squared in the equation. 3. Mass and velocity. 4. If the object is massless, therefore the K.E is zero. If the object is not moving (zero velocity), therefore the K.E is also zero. If the mass increases, the K.E also increases. If the velocity doubles, the K.E increases by a factor of four. 5. Mass and velocity is directly proportional to the K.E of an object. 6. Sample answers: A moving tricycle or car. A flying paper airplane. A person riding a skateboard. Activity #3: Jack and Hill 1. C 2. D 3. A 4. B
  • 47.
    44 Activity #4: Gameof Energetics 1. P.E 6. K.E 2. P.E 7. K.E 3. K.E 8. K.E 4. P.E 9. P.E 5. K.E 10. P.E Activity #5: PE and KE are PROBLEMatic! 1. P.E=30,000 Joules 2. K.E= 90,000 Joules 3. P.E=2352 Joules 4. K.E= 151.875 Joules 5. P.E =980 Joules Prepared by: SHEELA A. APOSTOL EDGAR A. SADDUL Tuguegarao City Science High School ENERGY SCOREBOARD POTENTIAL KINETIC 5 5
  • 48.
    45 SCIENCE 8 Name ofLearner: __________________________________ Grade Level: ____________ Section: __________________________________________ Date: ____________________ LEARNING ACTIVITY SHEET When Hotter, Faster or Slower? Background Information for the Learner Sound waves need a medium to be transmitted. The medium could be a solid, liquid or gas. Its speed through the medium is affected by some factors. One of the factors is temperature. When sound travels through dry air, its speed increases by 0.6 m/s per 1o C increase in temperature. The speed of sound at a certain temperature in air can be computed using the formula: v = 331m/s + 0.6m/s/o C (T). Where v is the speed of sound in air, 331 m/s is the speed of sound at 0 o C, 0.6m/s/o C is the increase in speed of sound per o C increase in temperature, and T is the temperature of air. In your past lessons about sound, you have learned that sound energy travels from one particle to another. As the temperature increases, the particles vibrate faster resulting to more collisions per unit time. With more collisions per unit time, sound energy is transferred more efficiently, and travel quickly. In this activity, you will be investigating the effect of temperature to the speed of sound by doing different activities. Learning Competency and Code Investigates the effect of temperature to speed of sound through fair testing (S8FE – Ie – 25)
  • 49.
    46 Activity 1. 3Pics, 1 Concept Directions: The diagram below shows the air temperature in some areas, and the speed of sound. Study the diagram and answer the questions that follow. Source: www.nde.ed.org/EducationResources/HighSchool/Sound/tempandspeed.html Questions: 1. What is the speed of sound at the lowest temperature given in the diagram? _________________________________________________________________ 2. What is the speed of sound at the highest temperature given in the diagram? _________________________________________________________________ 3. At what temperature where sound travels the slowest? _____________________ 4. At what temperature where sound travels fastest? _________________________ 5. How does temperature affect the speed of sound? _________________________________________________________________
  • 50.
    47 Activity 2. Solvefor v Directions: The table below shows some cities in the world and their recorded air temperature in a certain time. Using the formula v = 331m/s + 0.6m/s/o C (T), calculate the speed of sound in each given location. Record your answers in the table. Show your complete solution. Start with the given quantities, required or unknown, formula, solution, and final answer. A rubric will be used to evaluate your answers. Then, answer the questions that follow. Table 1. Speed of sound in some cities in the world at different temperature Location Temperature in ºC Speed (v) of sound in m/s Sapporo, Japan -4 Madrid, Spain 6 Wuhan, China 15 Tuguegarao City, Philippines 40 Write your complete solutions here: Sapporo, Japan Given: Required: Formula: Solution: Answer: Madrid, Spain Given: Required: Formula: Solution: Answer:
  • 51.
    48 Wuhan, China Given: Required: Formula: Solution: Answer: Tuguegarao City,Philippines Given: Required: Formula: Solution: Answer: Questions: 1. a. What city is relatively the hottest? __________________________________________ b. What is the speed of sound in this city? ______________________________________ c. Is it relatively the fastest? or slowest? ________________________________________ 2. a. What city is relatively the coldest? __________________________________________ b. What is the speed of sound in this city? ______________________________________ c. Is it relatively the fastest? or slowest? ________________________________________ 3. What is the effect of temperature to the speed of sound in air? _______________________ _________________________________________________________________________ Rubric for the problem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement
  • 52.
    49 Activity 3. Hotter,Faster Directions: Sound waves also travel through solid, and liquid like water. The table below shows the speed of sound in water at different temperature. Study the data, and answer the questions that follow. Table 2. Speed of sound in water at different temperature Temperature in ºC Speed of Sound in water (m/s) 0 1402 20 1482 100 1543 Questions: 1. What happens to the speed of sound in water when the temperature increases? __________________________________________________________________ 2. What happens to the speed of sound in water when the temperature decreases? __________________________________________________________________ 3. Based on the table, what is the effect of temperature to the speed of sound in water? ___________________________________________________________________
  • 53.
    50 Activity 3. Hotter,Faster Directions: Sound waves also travel through solid, and liquid like water. The table below shows the speed of sound in water at different temperature. Study the data, and answer the questions that follow. Table 2. Speed of sound in water at different temperature Temperature in ºC Speed of Sound in water (m/s) 0 1402 20 1482 100 1543 Questions: 1. What happens to the speed of sound in water when the temperature increases? __________________________________________________________________ 2. What happens to the speed of sound in water when the temperature decreases? __________________________________________________________________ 3. Based on the table, what is the effect of temperature to the speed of sound in water? ___________________________________________________________________
  • 54.
    51 Activity 4. #Relationship Directions:Given the data in Table 3 below, draw the graph properly and find out the relationship between the Temperature and the Speed of Sound. A Rubric will be used to check your graph. Table 3. Speed of sound at different temperature. Temperature in o C (Dry Air) Speed of Sound in m/s 0 331 9 336 22 344 30 349 44 357 Questions: 1. What is the shape of the graph? _____________________________________________________________________ 2. How does temperature affect the speed of sound? _____________________________________________________________________ 3. How does the speed of sound related to the temperature of a medium? _____________________________________________________________________ Relationship Between Temperature and Speed of Sound Temperature (o C) Speed of Sound (m/s)
  • 55.
    52 4. At whattemperature where the particles of air vibrate the fastest? ________________ 5. At what temperature where the particles of air vibrate the slowest? _______________ 6. Explain your answer in number 4 and 5 briefly. _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 7. At what condition where the speed of sound becomes zero? What is its possible implication? ____________________________________________________________________ ____________________________________________________________________ Rubric for the graph 5 4 3 2 1 Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in either X or Y axes are properly scaled. Numbers in both X and Y axes are not properly scaled. 5 data points are properly plotted. 4 data points are properly plotted. 3 data points are properly plotted. 2 data points are properly plotted. 1 or no data point is properly plotted. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. A line is drawn from one point to another point. No line is drawn Reflection: 1. I learned that _________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 2. I enjoyed most on _____________________________________________________ ____________________________________________________________________ ____________________________________________________________________ 3. I want to learn more on _________________________________________________ ____________________________________________________________________ ____________________________________________________________________
  • 56.
    53 References: Campo, Pia C.,et. al. 2003. Science-Grade 8. Learner’s Module. Pasig City. Department of Education. Young, Hugh D. and Freedman, Roger A. 2002. University Physics with Modern Physics. Singapore 629733. Pearson Education Asia Pte Ltd. www.nde.ed.org/EducationResources/HighSchool/Sound/tempandspeed.html
  • 57.
    54 Answer Key: Activity 1.“3 Pics 1 Concept” 1. What is the speed of sound at the lowest temperature given in the diagram? 330.4 m/s 2. What is the speed of sound at the highest temperature given in the diagram? 358.0 m/s 3. At what temperature where sound travels the slowest? - 1 ºC 4. At what temperature where sound travels fastest? 45 ºC 5. How does temperature affect the speed of sound? The higher the temperature, the faster the speed of sound; or The lower the temperature, the slower the speed of sound Activity 2. “Solve for v” Sapporo, Japan Given: T = -4 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (-4 ºC) Answer: v = 328.6 m/s Madrid, Spain Given: T = 6 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (6 ºC) Answer: v = 334.6 m/s Wuhan, China Given: T = 15 ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (15 ºC) Answer: v = 340.0 m/s Tuguegarao City, Philippines Given: T = 40ºC Required: v =? Formula: v = 331m/s + 0.6m/s/o C (T) Solution: v = 331m/s + 0.6m/s/o C (40 ºC) Answer: v = 355.0 m/s Rubric for the problem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement
  • 58.
    55 Table 1. Speedof sound in some cities in the world at different temperature Location Temperature in ºC Speed (v) of sound in m/s Sapporo, Japan -4 328.6 Madrid, Spain 6 334.6 Wuhan, China 15 340.0 Tuguegarao City, Philippines 40 355.0 1. What city is relatively the hottest? Tuguegarao City, Philippines What is the speed of sound in this city? 355.0 m/s Is it relatively the fastest? Or slowest? Fastest 2. What city is relatively the coldest? Sapporo, Japan 3. What is the speed of sound in this city? 328.6 m/s Is it relatively the fastest? Or slowest? Slowest 4. What is the effect of temperature to the speed of sound in air? The higher the temperature, the faster the speed of sound; or The lower the temperature, the slower the speed of sound Activity 3. “Hotter, Faster” 1. What happens to the speed of sound in water when the temperature increases? The speed of sound in water increases when the temperature increases. 2. What happens to the speed of sound in water when the temperature decreases? The speed of sound in water decreases when the temperature decreases. 3. Based on the table, what is the effect of temperature to the speed of sound in water? Sound travels faster when the temperature increases; or Sound travels slower when the temperature decreases. Activity 4. “#Relationship”
  • 59.
    56 Rubric for thegraph 5 4 3 2 1 Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in the X and Y axes are properly scaled. Numbers in either X or Y axes are properly scaled. Numbers in both X and Y axes are not properly scaled. 5 data points are properly plotted. 4 data points are properly plotted. 3 data points are properly plotted. 2 data points are properly plotted. 1 or no data point is properly plotted. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. Line that best fits the data points is properly drawn. A line is drawn from one point to another point. No line is drawn 1. What is the shape of the graph? Straight line graph (slanting to the right) 2. How does temperature affect the speed of sound? As the temperature increases, the speed of sound increases 3. How does the speed of sound related to the temperature of a medium? Speed of sound is directly proportional to the temperature. 4. At what temperature where the particles of air vibrate relatively the fastest? Particles vibrate fastest at 44 ºC 5. At what temperature where the particles of air vibrate relatively the slowest? Particles vibrate fastest at slowest at 0 ºC. 6. Explain your answer in number 5 briefly. The higher the temperature, the higher the kinetic energy of the particles, the faster they vibrate. 7. At what condition where the speed of sound becomes zero? What is its possible implication? The speed of sound becomes zero when the particles of a medium stop vibrating, having zero kinetic energy. This means that no sound can travel through the medium, no sound can reach the ears of the receiver, no sound can be heard. Prepared by: GEMMA U. PACAMALAN Cagayan National High School REOWIN PALATTAO Gosi National High School
  • 60.
    57 SCIENCE 8 Name oflearner: ____________________ Grade level: _______________ Section: ___________________________ Date______________________ LEARNING ACTIVITY SHEET Colors of Light Background Information for the Learners Have you seen a rainbow? When can you see a rainbow? A rainbow displays a unique band of colors. The colors we see are the result of sunlight hitting water drops where reflection, refraction and dispersion forms a rainbow. Water drops act as tiny prism separating sunlight into bands of colors. The colors of light are distinguished from each other by their different wavelengths and frequencies. The colors of light depend on their frequencies and wavelengths. Wavelength is the distance between two identical adjacent points in a wave while frequency is the number of waves that pass a fixed point in a unit time. The wavelengths and frequencies of the colors of light vary. The higher the frequency of the color of light, the greater is its energy. As the frequency of the color of light increase, the energy also increases. Red has the least frequency with the least energy and violet has the highest frequency and the highest energy. The spectral colors have the following characteristics; frequency, wavelength and energy. The color of light with longer wavelength travels slowly and has low frequency and energy. The color of light with shorter wavelength travels faster and has higher frequency and energy. Learning Competency and Code: Explain the hierarchy of colors in relation to energy. (S8FE-If-27-28)
  • 61.
    58 Activity 1. CompleteMe Directions: Unscramble the word/s to get the correct term and fill the appropriate blanks to complete the statements below. itwhehltig deeps dgbinen loroc repsidoin pmetsrcur calticriganle flecnoiter velewagnth lotatlanterniflecnoiter 1. Lights of different frequencies make up __________________. 2. ____________________band of colors obtained by dispersion of light. 3. Refraction is the _____________ of light when it travels from one medium to another of different optical densities. 4. __________________________ the process of separating light into a band of colors. 5. ______________________occurs when the angle of incidence is greater than the critical angle. 6. _________________property of light waves which is dependent on the frequency or wavelength of radiation that reaches the eye. 7. _______________________the angle of incidence in the denser medium resulting in angle of refraction of 900 . 8. ______________________property of light responsible for the formation of colors. 9. The ________________ of the different colors changes as it passes through the prism. 10. __________________ is the turning back of light when it hits a barrier.
  • 62.
    59 Activity 2. WhoAm I? Directions: The diagram below shows the separation of white light into different colors as it hits the prism. Color the refracted rays. Then, answer the questions that follow. 1. What do you call the process of separating white light into its components? __________________________________________________________________ __ 2. Which color is bent the most? ____________________________________________ 3. Which color is bent the least? _____________________________________________ 4. What do you call the bond of colors produced? _______________________________ 5. What are the component colors of a white light? ______________________________ _____________________________________________________________________ 6. What name or code could you give according to the hierarchy of colors? __________ Activity 3. Fact or Bluff Directions: Study the illustrations of wavelengths below. Given the following color descriptions, write Fact on the blank if it is true while Bluff if it is false. VIOLET RED _________1. Violet has longer wavelength. _________2. Red has shorter wavelength. _________3. Violet and red have the same wavelengths. _________4. Red has longer wavelength. _________5. Violet has shorter wavelength.
  • 63.
    60 Activity 4. RelateMe Directions: Draw and color the rainbow with the corresponding bond of colors in relation to its wavelength. 1. Which color represents the longest arc/ wavelength? ________________________ 2. Which color represents the shortest arc/ wavelength? ________________________ 3. What color appears at the top of the rainbow? Why? ________________________ ___________________________________________________________________ 4. What color appears at the bottom of the rainbow? Why? ______________________ ____________________________________________________________________ 5. Explain how wavelength is related in the position of colors in a rainbow? ____________________________________________________________________ ____________________________________________________________________
  • 64.
    61 Activity 5. ColorMe Directions: Color the spectrum wheel based on the given corresponding frequency, wavelength and energy.
  • 65.
    62 Activity 6. FillMe Directions: Using the illustration of Color Wheel in Activity 5, fill out the table with the corresponding wavelength, frequency and energy. Table 1 Frequency (Hz) Wavelength (m) Energy (eV) Red Orange Yellow Green Blue Violet Activity 7. Compare Me Directions: Study Table 1 to answer the questions below. 1. Compare the following color bonds using the descriptions (lower, higher, shorter, and longer). a. Red is _______________ in wavelength than violet. b. Yellow is _______________ in energy than blue. c. Violet is _______________ in frequency than red. d. Red is _______________ in energy than violet. e. Blue is _______________ in wavelength than red. 2. Which of the colors have the following characteristics? a. Longest wavelength? ______________ b. Shortest wavelength? ______________ c. Lowest frequency? ________________ d. Highest frequency? _______________ e. Highest energy? __________________ f. Lowest energy? __________________
  • 66.
    63 Activity 8. LinkMe Directions: Use the illustration of electromagnetic spectrum in answering the questions that follow. https://www.miniphysics.com/electromagnetic-spectrum_25.html 1. Does the frequencies of the colors of light increase from red to violet? ___________ 2. What did you observe about the wavelengths and frequencies of the colors of light? _____________________________________________________________________ 3. How is frequency related to energy of colors of light? _____________________________________________________________________ _____________________________________________________________________ 4. What did you observe about the corresponding energies from red to violet? _____________________________________________________________________ _____________________________________________________________________ 5. How will you explain the heirarchy of colors in relation to energy? _____________________________________________________________________ _____________________________________________________________________ Reflection: 1. I learned that __________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. I enjoyed most on ______________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. I want to learn more on __________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
  • 67.
    64 References: Campo, Pia C.,et. al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. Rabago, Lilia M., Ph.D.,et.al. 2001. Science and Technology IV: Physics Textbook for Fourth Year. Quezon City. Vibal Publishing House. Sotto, R.L., et. al. 2003. Science in Today’s World: Physics. Manila: Rex Bookstore, Inc. https://www.miniphysics.com/electromagnetic-spectrum_25.html https://www.youtube.com/watch?v=ASEdGwpyn58&t=4s https://www.youtube.com/watch?v=TvT3g8kU6SQ
  • 68.
    65 Answer Key: Activity 1-Complete Me 1. White light 2. Spectrum 3. bending 4. Dispersion 5. Total internal reflection 6. Color 7. Critical angle 8. Wavelength 9. Speed 10. Reflection Activity 2-Who am I? 1. Dispersion 2. Violet 3. Red 4. Spectrum 5. Red, orange, yellow, green, blue, indigo, violet 6. ROY G BIV Activity 3- Fact or Bluff 1. Bluff 2. Bluff 3. Bluff 4. Fact 5. Fact Activity 4 – Relate Me 1. Red 2. Violet 3. Red -- Red has longer arc / wavelength 4. Violet – Violet has short arc//wavelength
  • 69.
    66 Activity 5 ColorMe Activity 6 – Fill Me Frequency (THz) Wavelength (nm) Energy (eV) Red 422 700 1.77 Orange 484 620 2.00 Yellow 517 580 2.14 Green 566 530 2.34 Blue 638 470 2.6 Violet 744 400 2.95
  • 70.
    67 Activity 7- CompareMe 1. a. longer b. lower c. higher d. lower e. shorter 2. a. Red b. Violet c. Red d. Violet e. Violet f. Red Activity 8- Link Me 1. Yes. 2. The wavelengths and frequencies of the colors of light vary. The wavelength decreases from red to violet while the frequency increases from red to violet. 3. The higher the frequency of the color of light, the greater is its energy. 4. As the frequency of the color of light increase, the energy also increases. Red has the least frequency with the least energy and violet has the highest frequency and the highest energy. 5. The spectral colors have the following characteristics; frequency, wavelength and energy. The color of light with longer wavelength travels slowly and has low frequency and energy. The color of light with shorter wavelength travels faster and has higher frequency and energy. Prepared by: VENIE N. DE LEON Cagayan National High School
  • 71.
    68 SCIENCE 8 Name: ____________________Grade Level: _________________ Date: _____________________ Score: ______________________ LEARNING ACTIVITY SHEET Heat and Temperature Background Information for Learners Heat is often associated with temperature. In a typical life, one has to cook food using wood or other fuels like LPG. Burning fuels generate heat. Heat generated, on the other hand, is associated with increase in temperature. However, this is not always the case. Though heat and temperature are related to each other, they are two different concepts. The difference between these terms has something to do with the movement between atoms and molecules – the kinetic energy of substances. The Kinetic Molecular Theory of matter states that matter consists of particles that are constantly moving. Take into consideration the Figure 1 below. A B Figure 1: Boiling a 500 ml of water (A) vs 100 ml of water (B) Figure 1 above shows that regardless of the volume of water, the temperature of the two set-ups remain the same upon reaching their boiling points. There are more water molecules in beaker A containing 500 ml water, thus, requiring longer time for it to boil than 100 ml of water in beaker B. The higher the number of water molecules, the higher also is its heat /internal energy. Heat Temperature = 1000 C Temperature = 1000 C Heat
  • 72.
    69 Temperature is themeasure of hotness or coldness of a body and is measured by the use of thermometer (Madriaga et. al, 2013).It is the average kinetic energy which indicates the direction in which heat flows. Heat, on the other hand, is the energy that transfers from a body of higher temperature to another body of lower temperature through molecular collisions and cannot be directly measured. When heat is absorbed or given off by an object, its temperature changes. If heat is added to an object, the particles of the object move faster and the body’s temperature increases. If heat is transferred or removed from an object, the particles move slower and the body’s temperature decreases. As the thermal energy of a substance increases, its particles spread out and the substance expands in a process known as thermal expansion. Almost all materials expand when heated and contract when cooled (Padua et.al, 2010). Moreover, phase changes occur when heat is added to or removed from an object. Different materials also have the ability to absorb or release heat that result in temperature change. The amount of heat required by a material to increase its temperature of one-unit mass of a given material by one Celsius degree or by one Kelvin is called specific heat capacity (C). Padua et. Al, 2010). Learning Competency and Code Differentiate between heat and temperature at the molecular level. (S8FE-Ig-29)
  • 73.
    70 Activity 1: WordHunt Directions: Search the words being described in the sentences below. The answers may be found horizontally, vertically or diagonally. 1. It is a thermal sensor that measures temperature. 2. A process when matter changes from state to another. 3. A measure of the warmth of an object or substance. 4. A measure of relatively low temperature of an object or substance. 5. The energy that is contained within a system that is responsible for its temperature. 6. Increase in the size of a material. 7. The decrease in the size of a material. Source: Word Search Puzzle. Accessed June 8, 2020. Retrieved from http://puzzlemaker.discoveryeducation.com/code/BuildWordSearch.asp
  • 74.
    71 Activity 2: Heatvs. Temperature Directions: Choose the corresponding characteristics of heat and temperature on the choices given below. Write the letter of the correct answer on the space provided. A. It is a measure of hotness and coldness of a body. B. It is a form of energy that flows from a hotter region to the cooler region. C. It is measured in degree Celsius (o C), Fahrenheit (o F) or Kelvin (K). D. It is measured in calories (cal) or Joules (J). E. It depends on the speed of particles, the size and type of object. F. It does not depend on the mass of the object. Activity 3: Modified True or False Directions: Write TRUE if the statement is correct. Write FALSE if the statement is wrong and change the underlined word/s to make the statement correct. Write your answer on the space provided. ___________________________ 1. Liquid expands when heated. ___________________________ 2. Thermal expansion applies to solid and liquid. ___________________________ 3. Materials take up more space when heated ___________________________ 4. Solid expands more than liquid when heated. ___________________________ 5. The particles of liquid move freely when heated. ___________________________ 6. Water expands when cooled. ___________________________ 7. Molecules move far each other during contraction. ___________________________ 8. Only the spaces between particles changes during expansion and contraction. ___________________________ 9. Electrical wires could sag during hot days. ___________________________ 10. Tight bottle cap can easily open by putting it in hot water. What are the differences between Heat and Temperature? Heat • __________________ __________________ • __________________ __________________ • __________________ __________________ Temperature • _________________ _________________ • _________________ _________________ • _________________ _________________
  • 75.
    72 Activity 4: GoingPhase Change Directions: Write the letter of the missing data on the graph below showing the phase change of water. Choose your answer on the box. Then, answer the questions that follow. Phase change of water as heat is added Source: “Phase Change: Evaporation, Condensation, Freezing, Melting ...” Accessed June 4, 2020. https://spiral.ac/lesson-plan-ideas/clips/lessons/phase-change-evaporation- condensation-freezing-melting-sublimation-deposition. 1. What happens to the temperature and heat energy of a substance during a change of state? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. What happens when heat is added once the phase change is complete? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Heat Energy 5. ______________ 3._______ 6. Temperature 0o C 2. ________ 100o C A. vaporization D. G. melting B. E. ice C. sublimation F. liquid steam 4.________ _____ 1.________ _____
  • 76.
    73 3. What canyou infer about the relationship between phase change and heat energy? ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ Activity 5: Graph It Down Directions: Analyze the data below of the temperature change of different substances in a given time. Using the graph, plot the time in the x-axis vs the given values for each substance in the y-axis. Then, connect the graph of each of the three substances. Create a line graph for each substance below and answer the questions given. Use colored pen or crayon to connect the graph following the color coding below: Blue - water Yellow- sand Red - Iron Time (minutes) Temperature of the Substances (o C) Water Sand Iron 0 (initial) 25.0 o C 25 o C 25 o C 15mins 26.0o C 30o C 35 o C 30mins 27.5o C 35o C 45 o C 45mins 28.9 o C 40o C 55 o C 60mins 30.0 o C 45o C 65 o C Source: “Specific Heat Worksheet Answers.” Homeschooldressage.com, February 25, 2018. http://homeschooldressage.com/specific-heat-worksheet-answers/ A. Temperature vs. Heating Time Graph
  • 77.
    74 B. Answer thefollowing questions: 1. What is the order of the substances based on the time required to heat from slowest to fastest? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ 2. Which of these substances require more heat to increase in temperature? ___________________________________________________________________________ _________________________________________________________________________ 3. Which substances require more time to increase in temperature? ___________________________________________________________________________ _________________________________________________________________________ 4. When you boil water using a pot on the stove, which heats faster, the iron pot or the water? Explain your answer. __________________________________________________________________________ ___________________________________________________________________________ _________________________________________________________________________ 5. When you go to the beach you noticed that the sand is hotter than water although both are exposed under the heat of the sun. Why do you think this happens? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ 6. Based on the graph, which of the three substances has the highest specific heat capacity? Which substance has the lowest specific heat capacity? ___________________________________________________________________________ ___________________________________________________________________________ ________________________________________________________________________ Reflection: 4. I learned that _________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ 5. I enjoyed most on ____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ 6. I want to learn more on _________________________________________________
  • 78.
    75 _____________________________________________________________________ _____________________________________________________________________ __________________________________________________________________ References Madriaga, Estrellita A,Meliza P Valdoz, and Jonna M Abistado. 2013. Science Links. First Ed. Sampaloc, Manila, Philippines: Rex Book Store, Inc. Ocampo, Pia C. et.al. 2013 Science 8 Learner's Module. 1st ed. Pasig City, Philippines: Department of Education. Padua, Alicia L, and Ricardo M Crisostomo. 2010. Practical and Explorational Physics. Second ed. Quezon City, Philippines: Vibal Publishing House, Inc. Santos, Gil Nonato C., and Alfonso C. Danac. 2006. i-Physics (Investigatory Physics). Firsted. Sampaloc, Manila, Philippines: Rex Book Store, Inc. Website “Ninth Grade Lesson Introduction to Specific Heat ...” Accessed June 3, 2020. Retrieved from https://betterlesson.com/lesson/640676/introduction-to-specific-heat “Phase Change: Evaporation, Condensation, Freezing, Melting ...” Accessed June 4, 2020. Retrieved from https://study.com/academy/lesson/phase-change-evaporation-condensation-freezing- melting.html “Specific Heat Worksheet Answers.” Homeschooldressage.com, February 25, 2018. Retrieved from http://homeschooldressage.com/specific-heat-worksheet-answers/ “The Physics Classroom Tutorial.” The Physics Classroom. Accessed June 3, 2020. Retrieved from https://www.physicsclassroom.com/Class/thermalP/u18l1d.cfm Velez, Sierra. “Blendspace Created For Physical Science By Sierra Velez ...” Blendspace Created For Physical Science. Accessed June 3, 2020. Retrieved from https://www.tes.com/lessons/AX17cZ8TBxwrrg/blendspace-created-for-physical- science-by-sierra-velez “What Is Thermal Energy? (Article) | Khan Academy.” Accessed June 4, 2020. Retrieved from https://www.khanacademy.org/science/physics/work-and-energy/work-and-energy- tutorial/a/what-is-thermal-energy Word Search Puzzle. Accessed June 8, 2020. Retrieved from http://puzzlemaker.discoveryeducation.com/code/BuildWordSearch.asp
  • 79.
    76 Answer Key Activity 1:Word Hunt 1. Temperature 2. Phase change 3. Hotness 4. Coldness 5. Thermal Energy 6. Expansion 7. Contraction Activity 2: Heat vs. Temperature Heat- answer B, D and E Temperature- answer A, C and F Activity 3: Modified True or False 1. TRUE 6. heated 2. Solid, Liquid and Gas 7. Move closer 3. TRUE 8. Fact 4. TRUE 9. Fact 5. TRUE 10. Fact Activity 4: Going Phase Change A. 1. E. Ice 5. A. vaporization 2. B. 6. D. 3. H. melting 4. F. liquid B. 1. During a change of state, the temperature of a substance remains constant, while the thermal energy changes. 2. Once the phase change is complete, adding more heat causes the temperature to increase. 3. Heat energy is needed in phase change.
  • 80.
    77 Activity 5: Graphit Down A. Temperature vs. Heating Time Graph B. 1. Water- Sand- Iron 2. The water requires more heat to increase in temperature. 3. The water requires more time to increase in temperature. 4. The iron pot heats faster than the water because it requires less energy to heat up. It has lower specific heat capacity. 5. The sand is hot and the water is cold because the sea has to absorb more heat to raise its temperature than the sand. Water has higher specific heat capacity than the sand. 6. Water has the highest specific heat capacity and iron has the lowest specific heat capacity. Prepared by: KAREN C. GACUTAN Linao National High School
  • 81.
    78 SCIENCE 8 Name ofLearner: _______________________ Grade Level: _______________ Section: _______________________________ Score: ____________________ LEARNING ACTIVITY SHEET Relationship between Voltage and Current Background Information for Learners Electricity is almost an indispensable part of our lives. Lighting, heating, transportation, and communication are all dependent on it. When you connect an electric fan to an outlet, you are assembling and using an electric circuit. It consists of a source of electrical energy, connecting wires and a load. The three electrical quantities are current, I measures in amperes(A), voltage, V measures in volts(V) and resistance, R measures in ohms ( ). In an electric circuit, the voltage is the work done in moving or pushing the charged electrons (current) from one point to another in the circuit. The current in the circuit, on the other hand, is responsible for illuminating the bulb or in rotating the electric fan as the case maybe. The amount of current in the circuit is dependent upon the voltage applied. This amount of current can be indicated by the intensity of brightness in the case of a lighted bulb. Voltage, V is directly proportional to current, I, that is V I or V = k I Where k, the proportionality constant, is the slope of the V vs I graph. This constant k is equal to the resistance, R of the circuit, so R = V/I The unit of electrical resistance is defined as R = volt (V)/ampere (A) or ohm ( ) 1 = 1 V/A The relationship between voltage, current and resistance is known as Ohm’s Law, named after George Simo Ohm, who pioneered the study of such relation. Ohm’s law states that current, I is directly proportional to the voltage, V and inversely proportional to the resistance, R. In equation: I = V/R
  • 82.
    79 Most electric circuitswe see operate on more than one load called multiple load circuits. For instance, when you turn on light in the dining room, lamps in your bedroom remain unlighted, but if you remove one light bulb from Christmas bulbs, the other bulbs no longer light. Light bulbs in houses are connected differently from that of Christmas bulbs. The connection of light bulbs at home is called parallel while the Christmas light bulbs is in series. A series connection has two or more loads but current flows through a single conducting path while parallel connections has more than one path for current to flow. The figure below shows the differences between series and parallel connections. Fig.1: Series Connection Fig. 2: Parallel connection Applying Ohm’s law for series and parallel connections consider these equations below. Series connections IT = I1 = I2 = I3 … VT = V1 + V2 + V3 + … RT = R1 + R2 + R3 + … Parallel connections IT = I1 + I2 + I3 + … VT = V1 = V2 = V3 … _1_ = _1_ + _1_ + _1_ + … RT R1 R2 R3 This learning activity sheet will help you understand more of the relationship between voltage and current. Learning Competency with code Infer the relationship between current and voltage. (S8FE-Ig-30)
  • 83.
    80 Activity 1: Voltagevs. Current Directions: Complete the chart below to show comparison between voltage and current. Voltage Current Symbol Unit SI Unit Definition Relationship Voltage is the cause and current is the effect. Voltage can exist without current. Measuring Instrument Field created An electrostatic field In a series connection Current is the same through all components connected in series. In a parallel connection Voltages are the same across all components connected in parallel.
  • 84.
    81 Activity 2: TheBrighter, the Better Study the circuit diagrams below showing identical bulbs connected to a circuit with different number of batteries. Then, answer the questions that follow. Figure 3. Figure 4 . Figure 5. 1. Which configuration is the light brightest? ____________________________ 2. Which configuration has the greatest amount of current? _________________ 3. Which configuration is the light dimmest or least bright? _________________ 4. Which configuration has the least amount of current? ___________________ 5. If a single battery has a voltage of I.5 volts, what is the voltage of the circuit in figure 1? _____________________ 6. What is the total voltage of the circuit in figure 2? ______________________ 7. What is the total voltage of the circuit in figure 3? ______________________
  • 85.
    82 Activity 3. “FollowMe”, Relationship between Current and Voltage The figure below is the Experimental Set-up for finding the relationship between voltage and current. Analyze the data taken from the experiment and do the instructions that follow. Fig. 6 Data taken from the experiment: Table 1. Comparative Values of Voltage and Current at Fixed Resistance Number of Dry cells Voltage,V (Volts) Current, I (Ampere) Voltage,V /Current, I (Volt/Ampere) 1 1.5 0.15 2 3.0 0.30 3 4.5 0.45 4 6.0 0.60 1. Fill-up the fourth column of the table by dividing voltage, V by current, I. 2. Using the graph below, plot the data of voltage, V against Current,I.
  • 86.
    83 3. Draw aline of best-fit using the plotted points. 4. Describe the graph? ________________________________________________ 5. What does the graph indicate? ________________________________________ 6. What becomes of current, I as the voltage, V is increased?___________________ 7. What becomes of current, I as the voltage, V is decreased? __________________ 8. How will you describe the quotient when you divide voltage by current in column 4 of Table 1? 9. What electrical quantity represents this in the circuit? 10. What can you infer/conclude about the relationship between voltage and current for the same/constant load or resistor? __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Activity 4: Oh My Ohm’s Law Directions: Solve the following problems applying Ohm’s Law in the circuit. Show your complete solution. Start with the given quantities, required or unknown, formula, solution, and final answer. A rubric will be used to evaluate your answers. 1. How much current flows in an electric iron having a resistance of 20 when connected across 220-V line? 2. An electric heater uses 4A when 220-V are applied to its terminals. Determine its resistance.
  • 87.
    84 3. What isthe voltage across an electric hot plate which is draws 11A from the line when its hot resistance is 20 ? 4. What is the resistance of the coil of wire in an electric stove if it is connected to a 220V line and the current passing through it is 8A? 5. How much current flows through a lamp with a resistance of 75 when it is connected to a 220V line? 6. What is the resistance of a lamp which allows 10.9A when 220V is applied to it? 7. How much current would a 12 bread toaster draw when connected to a 220V outlet? 8. A resistor is connected to a 12V battery. The ammeter in the circuit reads 2A. What is the value of the resistance?
  • 88.
    85 9. If thevoltage in the circuit were doubled, what would happen to the current in the circuit? 10. If current in the circuit doubles of the same voltage, what will happen to the resistance in the circuit? Activity 5. Resistivity Affects Conductivity Directions: Use the table below to answer the questions that follow. Table 2: Resistivity of some materials at 200 C. Material Resistivity ( Silver 1.47 x 10-8 Copper 1.72 x 10-8 Gold 2.44 x 10-8 Aluminum 2.63 x 10-8 Tungsten 5.51 x 10-8 Steel 20.0 x 10-8 Mercury 95.0 x 10-8 Nichrome 100.0 x 10-8 Carbon 3.5 x 10-5 Source: Young, Hugh D. and Roger A freedom. University Physics with Modern Physics. 11th Ed. Pearson Wesley. 2004 1. Which of the given materials have the least resistivity? ________________________ As electrons flow through a conductor, they collide with the vibrating atoms of the conductor and these electrons transfer part of their energy to the atoms resulting to kinetic energy increases as manifested in the increase in the temperature of a conductor. The collision of the electrons with the atoms limits the amount of current in the conductor and this property of material is called resistivity which describe as measure of the material’s resistance to the passage of current. On the other hand, conductivity is the degree to which a specified material conducts electricity.
  • 89.
    86 2. Which ofthe given materials have the greatest resistivity? _____________________ 3. Explain why silver and gold are not used as household wirings despite of having the least resistivity. _____________________________________________________________________ _____________________________________________________________________ 4. Why is tungsten used as filament in lamps? _____________________________________________________________________ _____________________________________________________________________ 5. Why are copper wires used in household wiring? _____________________________________________________________________ _____________________________________________________________________ Activity 6. Connect Pa More Directions: Study the figures below to answer the following questions. Figure 7a Figure 7b 1. When you connect the four bulbs to a 12V power supply switch in series as shown in Figure 7a and turn the switch on, what happens to the other bulbs when you unscrew one light bulb? __________________________________________________________________________ 2. What if you will screw the one light bulb in Figure 7a, what do you observe? __________________________________________________________________________ 3. How do you describe this type of connection? __________________________________________________________________________ 4. When you connect the three bulbs to a 12V power supply as shown in Figure 7b and turn the switch on, what happens to the other bulbs when you unscrew one light bulb? ___________________________________________________________________________ ___________________________________________________________________________ 5. What if you will screw the one light bulb in Figure 7b, what do you observe? ___________________________________________________________________________
  • 90.
    87 6. How doyou describe this type of connection? ___________________________________________________________________________ 7. What is the difference between series connection and parallel connection based on your observations from the two set up? ___________________________________________________________________________ ___________________________________________________________________________ 8. What kind of connection is most practical at home? Why? ___________________________________________________________________________ ___________________________________________________________________________ 9. Why are electric meters connected in series with the rest of the circuits in the house? ___________________________________________________________________________ ___________________________________________________________________________ 10. Why is the main switch connected in series with the rest of the circuits in the house? ___________________________________________________________________________ ___________________________________________________________________________ Activity 7. Computation in a Connection Directions: Perform the indicated operations. Write the equations and solve for the unknown quantity. 1. Suppose there are four 30 bulbs are connected in series connected to a 220V line, what is the current in the circuit? Find the voltage drop in each of the four 30 bulbs. 2. You have five appliance connected in series as shown in the figure below. The refrigerator has a resistance of 20 , the TV set 10 , the radio 5 , the flat iron 75 and the electric stove 55 , what is a( total resistance in the circuit b) total current c) voltage drop in each appliance
  • 91.
    88 a. total resistancein the circuit b. total current c. voltage drop in each appliance 3. Using the figure below, solve for: a. Resistance of the combination b. Current through the ciruit
  • 92.
    89 c. Current througheach resistor d. Voltage across each resistor 4. Refer to the figure below to solve for: a. Resistance of the combination b. Current through the combination
  • 93.
    90 c. Current ineach resistor d. Voltage across each resistor 5. Consider the circuit below, determine the following: a. Voltage across each load, b. Current through each load,
  • 94.
    91 c. Total currentthrough the circuit, and d. Total resistance Reflection: 1. I have learned that _________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. I enjoyed most on __________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 3. I want to learn more on ________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ References: Acosta Herma D et.a. 2015. Science 10 Learner's Module. 1st ed. Pasig City: Department of Education. Arciaga, Marco E et. Al. 2008. Exploring Science and Technology. Paranaque City: Diwa Scholastic Press Inc. Benetillo, Eulalia N et. al. 2009. Science and Technology IV Textbook for Fourth Year. Revised Edition. Quezon City: Book Media Press.
  • 95.
    92 "Current vs Voltage."Diffen.com. Diffen LLC, n.d. Web. 13 Jun 2020.< https://www.diffen.com/difference/Current_vs_Voltage > Ocampo, Pia C. et.al. 2013. Science 8 Learner's Module. 1st ed. Pasig City: Department of Education. Padua L Alicia et. al. 2003. Practical and Exploration Physics. Quezon City: Vibal Publishing House Inc. Voltage, Current, Resistance and Ohm’s Law. Sparkfun Electronics. Accessed June 17, 2020. https://learn.sparkfun.com/tutorials/voltage-current-resistance-and-ohms-law Answer Key: Activity 1: Voltage vs. Current Voltage Current Symbol V I Unit V or volts or voltage A or Amp or amperage SI Unit 1 volt = 1 joule/coulomb. (V=W/C) 1 ampere =1 coulomb/second. Definition Voltage, also called electromotive force, is the potential difference in charge between two points in an electrical field. Current is the rate at which electric charge flows past a point in a circuit. In other words, current is the rate of flow of electric charge. Relationship Voltage is the cause and current is the effect. Voltage can exist without current. Current is the effect (voltage being the cause). Current cannot flow without Voltage Measuring Instrument Voltmeter Ammeter Field created An electrostatic field A magnetic field In a series connection Voltage gets distributed over components connected in series. Current is the same through all components connected in series. In a parallel connection Voltages are the same across all components connected in parallel. Current gets distributed over components connected in parallel.
  • 96.
    93 Activity 2: TheBrighter, The Better 1. Figure 5 2. Figure 5 3. Figure 3 4. Figure 3 5. 1 x 1.5 volts = 1.5 volts 6. 2 x 1.5 volts = 3.0 volts 7. 3 x 1.5 volts = 4.5 volts Activity 3: “Follow Me”, Relationship between Current and Voltage Table 1. Comparative Values of Voltage and Current at Fixed Resistance 1. 2 & 3 4. It is a straight line sloping upward to the right. 5. The graph indicates a direct relationship between Voltage and Current. 6. As the voltage, V is increased, the current, I is also increased. 7. As the voltage, V is decreased, the current, I is also decreased. 8. The answer is the same or constant Number of dry cells Voltage,V (Volts) Current, I (Ampere) Voltage,V/ Current, I 1 1.5 0.15 10 2 3.0 0.30 10 3 4.5 0.45 10 4 6.0 0.60 10
  • 97.
    94 9. The electricalquantity being described in this constant value is called resistance, R. 10. Current, I is directly proportional or dependent to voltage, V. For the same load or resistor, a uniform increase or decrease in voltage would result in a uniform increase or decrease in current. Activity 4. Oh My Ohm’s Law 1. Given: R=20 , V=220v Required: I Formula: I = V/R Solution: I = 220V/20 Answer: I = 11V/ or 11A 2. Given: I=4A, V=220V Required: R Formula: R=V/I = Solution: R = 220V/4A Answer: R = 55V/A or 55 3. Given: I=11A, R=20 Required: V Formula: V = IR Solution: V=(11A)(20 ) Answer: V = 220A.V or 220V 4. Given: V=220V, I=8A Required: R Formula: R = V/I Solution: R = 220V/8A Answer: R = 27.5V/A or 27.5 5. Given: R=75 , V=220V Required: I Formula: I = V/R Solution: I = 220V/ 75 Answer: I = 2.93V/ or 2.93A 6. Given: I=10.9A, V=220V Required: R Formula: R = V/I Solution: R = 220V/10.9A Answer: R = 20.18V/A or 20.18 7. Given: R=12 , V=220V Required: I Formula: I = V/R Solution: I = 220V/12 Answer: I = 18.33V/ or 18.33A 8. Given: V=12V, I=2A Required: R Formula: R = V/I Solution: R = 12V/2A Answer: R = 66V/A or 6
  • 98.
    95 9.The current, Iin the circuit also doubled 10.The resistance, R in the circuit was reduced to 50% Activity 5. Resistivity Affects Conductivity 1. Silver 2. Nichrome 3. Because melting point of silver is very low and if used as wire it could catch fire in a house while gold is very soft to be used as wires and expensive. 4. Tungsten is used as filament in bulbs of lamps because it has the highest melting point and lowest vapor pressure of all metals and at temperatures over 1 6500 C it has the highest tensile strength. 5. Copper wires are used in household wiring because these have very low resistances and are good conductors. Their resistances are not affected much by temperature changes. Activity 6. Connect Pa More 1. The other bulbs will not light up. 2. The four light bulbs lighted. 3. Series connection 4. The two remaining bulb will still light up 5. The three bulbs lighted 6. Parallel connection 7. In Figure 7a when you unscrew one bulb, the remaining bulbs in the circuit will not light up because there is only one path for the electrons to flow in the circuit while in Figure 7b, when you unscrew one bulb, the remaining bulbs will still lighted because the flow of electrons in the circuit is separated. 8. Parallel connection is widely used at home because not all appliances can be used at the same time. 9. Electric meters are connected in series with the rest of the circuit in the house to be able to measure the total amount of electrical energy entering in the household. 10. The main switch is connected in series with the rest of the circuits in the house to be able to control electrical energy entering the house in case of emergency Activity 7: Computation in a Connection 1. RT = R1 + R2 + R3 + R4 RT = 30 30 + 30 + 30 = 120
  • 99.
    96 IT = VT/RT =220V/120 = 1.83A IT= I1 = I2 = I3 = I4 V1 = I1R1 = 1.83A(30 = 54.9V V2 = I2R2 = 1.83A(30 = 54.9V V3 = I3R3 = 1.83A(30 = 54.9V V4 = I4R4 = 1.83A(30 = 54.9V VT= V1 + V2 + V3 + V4 = 219.6Vor 220V 2. a) RT = RT + RT + RT + RT = 20 + 10 + 5 + 75 + 55 = 165 b) IT = VT / RT = 220V/165 = 1.33A c) Iref = V1R1 = (1.33A) ( 00 ) = 26.6V ITV = V1R1 = (1.33A) ( 10 ) = 13.3V Iradio = V1R1 = (1.33A) ( 5 ) = 6.65V Iflat iron = V1R1 = (1.33A) ( 75 ) = 99.75V Istove = V1R1 = (1.33A) ( 55 ) = 73.15V 3. a) 1/ RT =1/ R1 + 1/R2 + 1/R3 1/ RT =1/ 2 + 1/4 + 1/6
  • 100.
    97 1/ RT =11/ 12 ( 11 RT)/ 11 = 12/11 RT = 1.09 b) IT = VT / RT = 6V / 1.09 = 5.50A c) I1 = V1//R1 I1 = 6V/ 2 IT = 3A I2 = V2//R2 I2 = 6V/ 4 IT = 1.5A I3 = V3//R3 I3 = 6V/ 6 IT = 1A d) VT = V1 = V2 = V3 = 220V 4. a) RT = R1 + R2 + R3 = 2 + 4 + 6 = 12 b) IT = VT / RT = 6V / 12 = 0.5A c) IT = I1 = I2 = I3 = 0.5A d) V1 = (I1 )(R1) = (0.5A) (2 ) = 1V V2 = (I2 )(R2) = (0.5A) (4 ) = 2V
  • 101.
    98 V3 = (I3)(R3) = (0.5A) (6 ) = 3V VT = V1 +V2 + V3 = 1V + 2V + 3V = 6V 5. a) Vt = V1 = V2 = V3 = 220V b) I1 = V1 / R1 = 220V / 240 = 0.92A I2 = V2 / R2 = 220V / 280 = 0.78A I3 = V3 / R3 = 220V / 300 = 0.73A c) It = I1 + I2 + I3 = 0.92A + 0.78A + 0.73A = 2.43A d) 1 / RT = 1/ R1 + 1/R2 + 1/R3 1 / RT = 1/240 + 1/280 + 1/300 1 / RT = 2232/21060 21060/2232 = 2232Rt/2232 99 = Rt
  • 102.
    99 Rubric for theproblem solving: 5 4 3 2 1 Five parts, namely Given quantity, Required or unknown, Formula, Solution, and Final answer are complete and properly written. Four parts are complete and properly written Three parts are complete and properly written One or Two parts are complete and properly written No part is properly written Each quantity involved has correct unit of measurement Each quantity involved has correct unit of measurement Three or four quantities have correct unit of measurement One or two quantities have correct unit of measurement Quantities have no unit of measurement Prepared by: MAPHILINDO C. TURARAY EDUARDO C. DELA ROSA Cagayan National High School
  • 103.
    100 SCIENCE 8 Name: ________________________________Section: __________________ Date: _________________________________ Score:____________________ LEARNING ACTIVITY SHEET Advantages and Disadvantages of Series and Parallel Connections Background Information for Learners From your previous lessons about electricity, you have learned that an electrical circuit consists of a load which can be electric bulbs or electrical appliances which consumes electrical power; a voltage source like batteries or generator which supplies electrical energy or a potential difference between two points within an electrical circuit allowing current to be flowing around it; and connecting wires which provides the path for electrons or current to flow. This electrical circuit can be connected either in series or parallel. Series connection has only one path or route for electrons or current to flow, hence, current is the same anywhere in the circuit. For example, if there are three bulbs connected in series, the bulbs will have a lesser brightness since the voltage (measure of strength of electrical power) is shared in ratio to resistance (limits or opposes the flow of electrical current). If one of the bulbs gets busted, the other two bulbs will not work properly or do not produce light since the flow of current is broken or disconnected. Furthermore, as the number of loads are increased in the series circuit, the greater circuit’s resistance is produced. Parallel connection on the other hand, has two or more paths or routes for the flow of current. This explains that the current splits or divides among the loads such as bulbs or appliances. In this case, the voltage across each pathway is the same throughout the circuit. For instance, if there are three bulbs of the same wattage connected in parallel, each bulb produces equal brightness. If one of the bulbs gets busted, the other bulbs will not be affected and still light up because each bulb has a separate connection to a voltage source in the circuit. In other words, if problem may occur in one of the connections in the circuit, other connections will not be affected, hence, current will still pass through in the undisturbed connections. This is the reason why parallel connections are preferred in household wirings because home appliances and other electrical devices operate on the same voltage and that loads or appliances are often switched on and off separately. Learning Competency with code: Explain the advantages and disadvantages of series and parallel connection in homes. (S8FE - Ii - 31)
  • 104.
    101 Activity 1: LabelMatters I. Directions. Name the two circuits according to the type of connection it represents. Write your answer on the blank below. A B Source: www.physicsclassroom.com ______________________ ________________________ II. Directions: Answer the following questions regarding circuits A and B above. 1. In circuit A, if bulb a burns out, will bulb c still light? _____ Why? __________________ _________________________________________________________________________ 2. In circuit A, if bulbs b and c burn out, will bulb a still light? _____ Why? _____________ _________________________________________________________________________ 3. In circuit B, if bulb d burns out, will bulb f still light? _____ Why? ___________________ _________________________________________________________________________ 4. In circuit B, if bulbs d and f are missing, will bulb e still light? _____ Why? ___________ _________________________________________________________________________ 5. Which do you prefer in your own household electrical wirings, series connection or parallel connection? Why? ___________________________________________________ ___________________________________________________________________________ _______________________________________________________________________ f [ T y p e a q u o t e f r o m t h e d o c u m e n t o r t h e s u m d c f [ f [ T y p e a q u o t e f r o m t h e d o c u m e n t o r t h e e b a
  • 105.
    102 Activity 2: IgniteYour Power to Analyze Directions: Study the illustration below and answer the questions that follow. Source: VectorStock.com/20558187 1. If the stand fan is switched off, will the other appliances still continue to work? Why? _________________________________________________________________________ 2. If the stand fan and television are not plugged into an outlet, will the refrigerator function? Why? ____________________________________________________________________ 3. If both the refrigerator and stand fan are unplugged, will the television still work? Why? _________________________________________________________________________ 4. If all appliances are plugged into individual outlets, does it affect the voltage source? Why? ____________________________________________________________________ 5. Appliances at home are usually connected in parallel. What are the advantages of having a parallel connection in household electrical connection? ____________________________ _________________________________________________________________________
  • 106.
    103 Activity 3: Glowin the Dark Directions: Analyze the illustrations below and answer the questions that follow. 1. If bulb a is removed from the circuit, will the rest of the bulbs or appliances still work? Why? _________________________________________________________________ 2. What happens to the entire circuit if bulb c get busted? __________________________ ______________________________________________________________________ 3. If two more bulbs are added in the circuit, will the brightness be the same as that of the three bulbs? Why? _______________________________________________________ _______________________________________________________________________ 4. What happens to the entire circuit if the stand fan is damaged? ____________________ _______________________________________________________________________ 5. How are the appliances and electric bulbs connected in the circuit? Is this type of connection possible? Why or why not? ________________________________________ ________________________________________________________________________ ________________________________________________________________________ a b c
  • 107.
    104 Activity 4: ExploreYour Bright Side Directions: Seek the assistance of your parents to inspect your household electrical connections and answer the following guide questions. 1. Which loads or appliances are connected in series? ____________________________________________________________________ 2. Which loads or appliances are connected in parallel? ____________________________________________________________________ For items 3 and 4, refer to the given situation below: One morning, your mother is ironing your uniform with a stand fan on and a light bulb on. Suddenly, the light bulb sparked and eventually got busted. 3. If the electric iron, stand fan and the bulb are connected in series, can your mother still continue to iron your clothes? Why? _____________________________________ ___________________________________________________________________ 4. If the electric iron, stand fan and the bulb are connected in parallel, can your mother still continue to iron your clothes? Why? ______________________________________ ___________________________________________________________________ 5. What are the advantages and disadvantages of series connection? How about the advantages and disadvantages of parallel connection? Complete the table below. Series Connection Parallel Connection Advantages Disadvantages
  • 108.
    105 Activity 5: SparkYour Best Option Directions: Given the situations below, select one of your best choice and work for it. 1. Draw a poster about the advantages and disadvantages of series and parallel connections in homes. 2. Create a two-minute promotional video on the advantages and disadvantages of series and parallel connections in homes. 3. Make a rap song in the form of audio-video about the advantages and disadvantages of series and parallel connections in homes. Rubric for Scoring POSTER MAKING CATEGORY Excellent 4 Good 3 Fair 2 Needs Improvement 1 Graphics - Clarity Graphics are all in focus and the content easily viewed and identified from 6 ft. away. Most graphics are in focus and the content easily viewed and identified from 6 ft. away. Most graphics are in focus and the content is easily viewed and identified from 4 ft. away. Many graphics are not clear or are too small. Graphics - Originality Several of the graphics used on the poster reflect a exceptional degree of student creativity in their creation and/or display. One or two of the graphics used on the poster reflect student creativity in their creation and/or display. The graphics are made by the student, but are based on the designs or ideas of others. No graphics made by the student are included. Graphics - Relevance All graphics are related to the topic and make it easier to understand. All borrowed graphics have a source citation. All graphics are related to the topic and most make it easier to understand. All borrowed graphics have a source citation. All graphics relate to the topic. Most borrowed graphics have a source citation. Graphics do not relate to the topic OR several borrowed graphics do not have a source citation.
  • 109.
    106 Labels All items of importanceon the poster are clearly labeled with labels that can be read from at least 3 ft. away. Almost all items of importance on the poster are clearly labeled with labels that can be read from at least 3 ft. away. Several items of importance on the poster are clearly labeled with labels that can be read from at least 3 ft. away. Labels are too small to view OR no important items were labeled. Required Elements The poster includes all required elements as well as additional information. All required elements are included on the poster. All but 1 of the required elements are included on the poster. Several required elements were missing. Knowledge Gained Student can accurately answer all questions related to facts in the poster and processes used to create the poster. Student can accurately answer most questions related to facts in the poster and processes used to create the poster. Student can accurately answer about 75% of questions related to facts in the poster and processes used to create the poster. Student appears to have insufficient knowledge about the facts or processes used in the poster. Content - Accuracy At least 7 accurate facts are displayed on the poster. 5-6 accurate facts are displayed on the poster. 3-4 accurate facts are displayed on the poster. Less than 3 accurate facts are displayed on the poster. Attractiveness The poster is exceptionally attractive in terms of design, layout, and neatness. The poster is attractive in terms of design, layout and neatness. The poster is acceptably attractive though it may be a bit messy. The poster is messy or very poorly designed. It is not attractive.
  • 110.
    107 VIDEO PRESENTATION Criteria Excellent 4 Good 3 Fair 2 Needs Improvement 1 ContentIt covers all the topics in depth with details and examples. The knowledge of the topic is excellent. It includes basic knowledge about the topic. The content seems to be good. It includes essential information about the topic but it has 1-2 mistakes in the facts. The content includes minor details and it has several mistakes in the facts. Originality The product shows great originality. The ideas are creative and witty. The product shows certain originality. It shows the use of new ideas and of shrewdness It uses ideas from other people (quoting them0, but there is little evidence of original ideas Uses ideas from other people without quoting them. Use of Language There are no mistakes in spelling or grammar Three or fewer spelling mistakes or punctuation mistakes Four spelling or grammar mistakes More than four spelling or grammar mistakes Videography- Interest A lot of different shots, camera angles, sound effects, and an adequate use of zooming providing variety in the video. Several (3-4) and different shots, camera angles, sound effects, and/or an adequate use of zooming providing variety in the video. One or two different shots, camera angles, sound effects, and/or an adequate use of zooming providing variety in the video. Little effort has been made to provide variety in the video. Videography- Clarity The overall quality of the video and the focus were excellent. Most of the quality of the video and the focus were excellent. The quality of the video is not very good but the overall focus was excellent The quality of the video and the focus are not very good.
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    108 RAP MUSIC Criteria ExcellentGood Fair Accurate All information was accurate in rap There are many inaccuracies You rap’s information was very inaccurate Detailed Your rap was very detailed. I felt like I really knew your person and what he/she stood for Your rap gives some details about your person, but I felt it was lacking some specifics Your rap and visual are too general, I could have made it up just by guessing about the person and how they had great ideas Thorough Your rap and visual covered all essential beliefs and facts about your person Your rap and visual covered a few major points about your person Your rap and visual only covered one main idea. Reflection 4. I have learned that ___________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________. 5. I enjoyed most on ____________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 6. I want to learn more on _______________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
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    109 References: Bentillo, Eulalia. 2012Physics, Science and Technology. Quezon City, Philippines. FEP Printing Corporation. Campo, Pia. et.al. 2016. Science Learners Module. Pasig City, Philippines: FEP Printing Corporation. https://www.google.com/search www.physicsclassroom.com https://www.qoura.com/search https://www.google.com/search?q=high+school+rubrics+for+poster&tbm=isch&ved=2ahU KEwib_Y_Rm-_pAhULvJQKHZARBusQ2- https://www.google.com/search?q=high+school+rubrics+for+video+presentation&tbm=isch &ved=2ahUKEwib_Y_Rm_pAhULvJQKHZARBusQ2- https://www.google.com/search?q=high+school+rubrics+for+a+rap+song&tbm=isch&ved= 2ahUKEwjx3u6bzunpAhVD3pQKHWyNBqIQ2cCegQIABAA&oq=high+school+ru brics+for+a+rap+song&gs_lcp=CgNpbWcQAzoCCAA6BggAEAgQHlDDthRYk- YUYL_xFGgBcAB4AIAB
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    110 Answer Key Activity 1 I.A B Series Parallel II. 1. No, because the flow of current is broken. 2. No, because the flow of current is broken. 3. Yes, because each bulb is individually connected to a voltage source. 4. Yes, because each bulb is individually connected to a voltage source. 5. Parallel, because even if one of the loads is broken, the rest of the loads will not be affected. Activity 2. 1. Yes. Because each appliance has its own path where current flows. 2. Yes. Because electrons or current follow different paths as they flow from negative to positive terminal. 3. Yes. Because it does not affect the paths of the other appliances for current to flow. 4. No. Because all appliances connected in parallel operate with the same voltage source. 5. Parallel connection is preferred over series connection at home for reasons that all appliances operate with the same voltage that is 220V and aside from that, if one of the appliances will be damaged, the other appliances will still function. Unlike in series connection, if one of the appliances will be damaged, the rest of the appliances will no longer work or will no longer function. Activity 3. 1. No. Because the flow of electrons or the flow of current is broken or cut. 2. If bulb c get busted, the rest of the circuit will no longer work. 3. No. Because in series connection, the voltage is shared in ratio to resistance. Hence, the bulbs become dimmer. 4. If the stand fan is damaged, the entire circuit will not function anymore because the path where current flows is disconnected. 5. No. The reason why homes aren’t connected in series is that, the voltage across each appliance will be dropped and so, the last appliance will not get sufficient voltage to drive current and if that happens, some of the appliances will not function well. Aside from that, once you switched off the light during daytime, none of the appliances will
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    111 work. Subsequently, iflights are switched on during night time, the rest of the appliances will also work and so, unnecessary energy is consumed. Activity 4. 1. The main switch is connected in series with the rest of the loads or appliances at home. 2. Appliances like television, refrigerator, electric fans, electric pot, light bulbs and other electrical appliances are connected in parallel. 3. No. Because the path for current to flow has been disconnected. 4. Yes. Because current can still flow or travel along a different path. 5. Series Connection Parallel Connection Advantages Current flows through every component in the circuit. It is useful when you need to maintain a constant current through each component example in Christmas lights All loads or appliances connected in the circuit gets equal amount of voltage; it does not affect the entire circuit even if one of the loads is being damaged and that current can still pass through the circuit. Disadvantages If you are going to add more output devices, the slower the current becomes and once the circuit is broken, the entire circuit will no longer function It requires a lot of wires in connecting each appliance. There could be a risk of fire in some cases and increasing the number of output devices does not increase the resistance. Prepared by: DIANA D. LACAMBRA Cataggaman National High School
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    112 SCIENCE 8 Name ofLearner: _______________________________ Grade Level:_________________ Section:________________________________________ Date: ______________________ LEARNING ACTIVITY SHEET Electrical Safety Devices Background Information for the Learners Electricity is very essential. It provides us so many valuable things without which life on earth would be difficult. It gives us light and enables us to enjoy some comfort. It also facilitates the performance of certain tasks. But despite its many benefits, electricity could bring danger like the most common house fires and electrocution, which is so fatal. Electrical engineers or electricians often use safety equipment or devices to protect the building as well as the people from injury due to electric shock in the human body. Grounding wires protect people from shocks. If a short circuit occurs in a device, current will go directly into the earth through a low resistance grounding wire. In this way a person who touches the device will be protected. In order to protect people from shocks, electrical systems are grounded. A circuit is electrically grounded when charges are able to flow directly from the circuit into the ground connection in the event of a short circuit. The following are some electrical safety devices (ESD) used in electric circuit that are found in our homes and their functions. 1. Circuit breaker is a safety device that uses an electromagnet that automatically shut off the circuit when there is an excess current from overload or short circuit. It’s easy to reset the circuit breaker. This is done by pulling back a switch after turning off some of the appliances that are causing the high current in the circuit. 2. Fuse is a device that contains a thin strip of metal that will melt if too much current flows through it. It protects the load such as appliances from damaging effects of overcurrent. When the strip of metal melts, or “blows”, it breaks the circuit and stops the flow of current. The electricity might have gone out because a fuse was blown. Once the overload is corrected, the fuse can be replaced and the electricity is restored. When a fuse burns out, it cannot be used again. circuit breaker fuse
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    113 3. Three-pronged plug.The two flat prongs connect the appliance to the household circuit. This third prong, which is round, connects the metal shell of an appliance to the ground wire of a building. It serves as a ground conductor in order to protect people from electrocution. 4. Lightning rod is a metal rod mounted on the roof of a building in order to protect a building. It is also connected to a grounding wire. When lightning strikes the rod, charges flow through the rod, into the wire and then into the Earth. This protects the building from lightning. 5. Double insulation protects the user of the appliance from an electric shock by preventing any possibility of the external casing becoming live thus, eliminating the need for an earth connection. Some appliances have double insulation, and only need live and neutral wires. They don’t need an earth wire e.g. televisions, computers, printers, and hairdryers. 6. Earthing is the act of connecting the metal casing of the appliance to earth via a wired connection to the bare ground. Earthing wires usually have green and yellow bands around them. It is also a method of transmitting the instant electricity discharge directly to the ground through lower resistance wires or electrical cables. This is one of the significant features of electrical networks. Because it builds the most eagerly accessible and hazardous power source much secure to utilize. Learning Competency with Code: Explain the functions of circuit breakers, fuses, earthing, double insulation and other safety devices in the home. (S8FE-Ii-33) Plug with third prong lightning rod Earthing
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    114 Activity 1. Let’sMake Connection! Directions: Match the devices in Column B and their respective functions in Column C with the given pictures of items in Column A. Write your Coded answer in the space provided. The first one is done for you. Column A Picture Column B Device name Column C Function Column D Coded answer 1. A. Circuit Breaker I. Connects the metal shell of an appliance to the ground wire of a building 1. C, II 2. B. Double insulation II. Transmits the instant electricity discharge directly to the ground through lower resistance wires or electrical cables 2. 3. C. Earthing III. Protects the building from lighting discharge 3. 4. D. Fuse IV. Shuts off the circuit when the current gets too high using an electromagnet 4. 5. E. Lightning Rod V. Protects the user of the appliance from an electric shock 5. 6. F. Third Prong VI. Melts if too much current flows through it 6.
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    115 Activity 2. CanYou Be My Partner? Directions: Fill in the Venn diagram comparing circuit breaker and a fuse by transferring the sentences below into their appropriate places. Circuit breaker Fuse 1. ______________________ 1. ______________________ _____________________ ______________________ _____________________ ______________________ 2. ____________________ 1. ___________ 2. ______________________ ___________________ ___________ ______________________ ___________________ ___________ ______________________ 2. ___________ ___________ ___________ It looks like switches Protects wiring from overheating It contains a thin strip of metal Uses electromagnet to shut off It burns out and can’t be used again Safety devices that break the circuit whenever overload or short occurs
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    116 Activity 3. Factor Bluff? Directions: Write FACT if the statement is correct and write BLUFF if the statement is wrong and give the correct term in the underlined word to correct the statement. Write your answer on the space provided. 1. The human body can be seriously injured by shocks, even those of less than one ampere. ________________________________ 2. Wearing of rubber shoes or slippers when repairing electric appliances is one of the safety measures in handling electricity. ____________________________ 3. Always plug an electrical appliance before attempting to open or repair it. _________________________________ 4. Never replace a blown fuse with coin or just any wire. _________________________ 5. Never overload a circuit by attaching too many appliances to it. __________________ 6. Always replace a blown fuse with a coin or just any wire. _______________________ 7. Don’t ignore switches or outlets that don’t work. Have a qualified electrician check the outlets. ___________________________ 8. Don’t use old extension cords without inspecting them first. ____________________ 9. Don’t switch on electric appliances with wet hands. ___________________________ 10. Pull on the plug, not on the cord to disconnect electrical appliance from the outlet. ________________________ Activity 4. Safety First! Directions: Answer the following questions. 1. What are some important safety devices used in your own homes? Name at least 3 of these electrical devices. ________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 2. How should you prevent electric shock or electrocution? ______________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ 3. What will happen to fuse if it burns out? ___________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
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    117 4. Why doesconnecting too many electrical appliances at the same time in one extension wire with low quality often” blow “ or “burn” a fuse? _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ Reflection: 1. I learned that ______________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. I enjoyed most on __________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 3. I want to learn more on _____________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ References and Link/s: Acosta, Herma D.et.al. 2015. Science –Grade 10.Learner’s Material. Pasig City. Department of Education . Bentillo, Eulalia N. et .al. 2004. Physics, Science and Technology Textbook for Fourth. Quezon City. Department of Education . Campo, Pia C., et. al. 2003. Science – Grade 8. Learner’s Module. Pasig City. Department of Education. Holt, Rinehart and Winston, Holt. 2001.Science and Technology, Physical Science. Austin, Texas. A Harcourt Classroom Education Company. Austin, Texas. Padilla, Michael J.et. al. 2001. Focus on Physical Science. Prentice Hall. New Jersey Glenview, Illinois, https://www.gcsescience.com/pe38.htm https://www.thespruce.com/six-ways-of-prevent
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  • 122.
    1. C, II 2.E, III 3. B, V 4. A, IV 5. F, I 6. D, VI Activity 2. Circuit breaker Fuse 1. It looks like switches ___ 1. It contains a thin strip of _____________________ metal. _____________________ ______________________ 2. Uses electromagnet to 1. Protect wiring 2. It burns out and can’t be used shut off __________from overheating again. ___________________ ___________ ______________________ 2. Safety devices that break the circuit whenever over- load or short occurs Activity 3. 1. Fact 6. Bluff, Never 2. Fact 7. Fact 3. Bluff , Unplug 8. Fact 4. Fact 9. Fact 5. Fact 10. Fact Activity 4. 1. Answers vary (fuse ,circuit breaker, ground conductor ,prong)
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    2. Possible answers a.Do not “flip”the circuit breaker as ON and OFF switch b. Do not replace the burn fuse without putting down the main switch. c. Never use a coin or piece of metal to replace a burn fuse. d. Do not use old extension wires without inspecting them first. e. Check the extension cord load limit. f. Have a qualified or licensed electrician inspect the circuit breaker, fuse, switches that don’t work anymore. g. Unplug electrical appliances when not in use. 3. The color of the metal wire is black. If a fuse burns out no current will flow and all lights and fixtures along the circuit go dead. It has to be replaced with new one. 4. If too many appliances are connected in a single extension cord this is overloading. Overloading occurs when an electrical wires carries too much current. This may cause the fuse wire to melt or burn because it exceeds the maximum current the household wire can handle. Prepared by: VICTORIA T. IRINGAN Cagayan National High School