3. 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
4. 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.
5. 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
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. 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? __________________________________
8. 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 _________________.
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 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.
11. 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? _________________________
____________________________________________________________________
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. 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?
_____________________________________________________________________
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. 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
16. 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 ____________________________________________________
________________________________________________________________________
________________________________________________________________________
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.
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
19. 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
20. 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.
21. 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).
22. 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
23. 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.
24. 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
25. 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.
26. 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.
27. 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:____________
28. 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
29. 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
30. 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
32. 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 _______________________________________________
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________
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 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
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 of Learner: ______________________ Grade Level: _______________
Section: ______________________________ Date: _____________________
LEARNING ACTIVITY SHEET
Potential Energy and Kinetic Energy
Background Information for the Learners:
Read the comic strips.
38. 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
39. 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.
___________________________________________________________________________
___________________________________________________________________________
40. 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
41. 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.
42. 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.
43. 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?
44. 41
REFLECTION:
1. I learned that
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
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: 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
48. 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)
49. 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?
_________________________________________________________________
50. 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:
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 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 _________________________________________________
____________________________________________________________________
____________________________________________________________________
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. 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”
59. 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
60. 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)
61. 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.
62. 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.
63. 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?
____________________________________________________________________
____________________________________________________________________
64. 61
Activity 5. Color Me
Directions: Color the spectrum wheel based on the given corresponding frequency,
wavelength and energy.
65. 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? __________________
66. 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 __________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
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 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
70. 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
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 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)
73. 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
74. 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
• _________________
_________________
• _________________
_________________
• _________________
_________________
75. 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.________
_____
76. 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
77. 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 _________________________________________________
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: 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
81. 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
82. 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)
83. 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.
84. 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? ______________________
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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.
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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.
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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?
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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.
