PHYSICAL SCIENCE REVIEWER for Incoming Grade 7

1. ENHANCED SCIENCE
GRADE 7
(Reviewer)
BY: Jimnaira U. Abanto

2. Science from Curiosity
OCuriosity is the basis of science. It
provides questions but is seldom
enough to achieve scientific results.
OScience is a system of knowledge
and the methods you used to find
that knowledge. And it begins with
curiosity and often ends with
discovery.

3. Science and Technology
O Technology is the use of knowledge to
solve practical problems.
GOAL of Science and Technology
O Science is TO EXPAND KNOWLEDGE.
O Technology is TO APPLY THAT
KNOWLEDGE

4. Branches of Science

5. Scientific Method
OIt is an organized plan for gathering,
organizing, and communicating
information.
Goal:
To better understand an observed
event.

6. Make
observation
Ask question
Develop
hypothesis
Test hypothesis
with an
experiment
Analyze data
and Draw
Conclusions

7. When you walk or run in
the rain, you get wet
How does your speed
affect how wet you get
when you are caught in
the rain?
You might predict that
the faster your speed,
the drier you will stay in
the rain.
Variable- any factor that can change.
Manipulated variable – the variable that causes a
change in another
Responding variable – the variable that changes
in response to the manipulated variable.
Controlled Experiment – is an experiment in
which only one variable, the manipulated variable
is deliberately changed at a time. While the
responding variable is observed for changes, all
other variables are kept constant or controlled.
Running in the rain
keeps you drier than
walking—about 40%
drier.

8. Theory & Law
O Scientific theory
It is a well-tested explanation for a set of
observations or experimental results. Theories never
proved. Instead, they become stronger if the facts
continue to support them. However, if an existing theory
fails to explain new facts and discoveries, the theory may
be revised to a new theory may replace it.
O Scientific Laws
It is a statement that summarizes a pattern found
in nature. And it describes an observed pattern in nature
without attempting to explain it. The explanation of such a
pattern is provided by a scientific theory.

9. Measurements
O Using Scientific Notation
Scientific Notation is a way of expressing a value
as the product of a number between 1 and 10 and
a power of 10.
Ex. 300,000,000—3.0 x 108
0.00086 --- 8.6 x 10-4
O It makes very large or very small numbers
easier to work with.

10. O SI Units. Scientists use a set of measuring units
called SI, or the International System Units.
SI Base Units Derived Units
Quantity Unit Symbol Quantity Unit Symbol
Length Meter M Area Square meter m2
Mass Kilogram Kg Volume Cubic meter m3
Temperature Kelvin K Frequency Hertz(1/s) Hz
Time Second S Electric charge Coulomb(Axs) C
Amount of
substance
Mole Mol Density Kg per Cubic meter Kg/m3
Electric current Ampere A Pressure Pascal(kg/mxs2) Pa
Luminous
intensity
Candela Cd Energy Joule(kgxm2/s2) J

11. SI Prefixes
Prefix Symbol Meaning Multiply Unit by
Giga- G billion(109) 1 000 000 000
Mega- M million(106) 1 000 000
Kilo- K thousand(103) 1 000
Deci- D tenth(10-1) 0.1
Centi- C hundredth(10-2) 0.01
Milli- M thousandth(10-
3)
0.001
Micro- µ millionth(10-6) 0.000001
Nano- N billionth(10-9) 0.000000001

12. O Conversion Factor
is a ratio of equivalent measurements that is
used to convert a quantity expressed in one unit to
another unit.
Ex. 8848 m to km
8848 𝑚
1𝑘𝑚
1000𝑚 = 8.848 km

13. O Measuring Temperature
Common Temperatures
Fahrenheit(oF) Celsius(oC) Kelvin (K)
Water boils 212 100 373
Human body 98.6 37 310
Average room 68 20 293
Water freezes 32 0 273
• You can convert from one scale to other by using one of the
following formulas.
℃ =
5
9
(℉ − 32) ℉ =
9
5
℃ + 32 𝐾 = ℃ +
273

14. Significant Figures
-- all digits, including the last number. The number of SF indicates the
exactness of measurement.
Guidelines:
O All non-zero digits are significant. Ex. a. 29685 – 5 b. SF 286.9 = 4 SF
O A zero that appears between two non-zero digits is significant.
Ex. a. 206059 = 6SF b. 4.008= 4SF
O Zeros that appear to the left of an understood decimal point but the right or
a non-zero digit are not significant(unless otherwise indicated)
Ex. 890,000,000 = 2SF
O Zeros to the left of an expressed decimal point and to the right of non-zero
digit are significant. Ex. a. 5280=4SF b. 104800=6SF
O Zeros to the right of a decimal point but to the left of a non-zero digit are
not significant. Ex. 0.00129 = 3SF
O Zeros to the right of a decimal point and to the right of a non-zero digit are
significant. Ex. 0.0510 = 3SF 16.000= 5SF
*In decimal numbers less than one, the zero that is placed to the left of
the decimal point is never significant.

15. ASSESSMENT
(Reviewing Content)

16. Question
OThe application of knowledge to
solve practical problems is known
as
a. Science
b. Curiosity
c. Technology
d. Experimentation

17. Question
OWhich is not a branch of natural
science?
a. Physical Science
b. Life Science
c. Earth Science
d. Social Science

18. Question
OWhat is the purpose of an
experiment?
a. To communicate data
b. To test a hypothesis
c. To prove a scientific law
d. None of the above

19. Question
OWhich value is equivalent to 5 x 106
a. Five thousand
b. Five million
c. Fifty thousand
d. Fifty million

20. Question
OIn a controlled experiment,
a. There are multiple responding variables
b. The responding variable is kept constant
c. The manipulated variable is kept
constant
d. The responding variable is deliberately
changed
e. Only one variable at a time is
deliberately changed

21. Question
O The speed of an object indicates how far it travels
in a given amount of time. If an electron travels
2.42 x 108 meters in 2 seconds, what is the speed
of this electron in cm/s?
a. 1.21 x 108 cm/s
b. 4.83 x 108 cm/s
c. 1.21 x 1010 cm/s
d. 2.42 x 1010 cm/s
e. 4.84 x 1010 cm/s

22. Question
OA doctor measures the temperature of a
patient to be 101 oF. What is this
temperature in kelvins?
a. 38.3 K
b. 214 K
c. 346 K
d. 73.8 K
e. 311 K

23. Question
O A student conducts an experiment by dropping a
basketball and a box of cereal of the same weight from
the top of a building. The student measures the time it
takes for each object to strike the ground. What was
the student’s hypothesis?
a. A basketball weighs more than cereal
b. Curved objects travel through the air faster than the
flat objects
c. Heavier objects travel through the air faster than the
lighter object
d. Gravity pulls on objects of the same weight with the
same force
e. Heavier objects strike the ground with a greater force
than the lighter objects.

24. Question
OIf two variables are directly proportional,
then
a. An increase in one variable causes a
decrease in the other variable
b. The product of the two variables is
constant
c. The ratio of the two variable is the
controlled variable
d. Neither variable is the controlled variable
e. Both variables are constant

25. CHEMISTRY
 Composition
 Structure
 Properties
 Reaction
MATTE
R

26. MATTER
PURE
SUBSTANCE
ELEMENTS COMPOUNDS
MIXTURE
SOLUTIONS
SUSPENSIONS COLLOIDS

27. 1. Pure substances, or a simply
substance.
OElement – is a substance that cannot be
broken down into simpler substances. It
has a fixed composition because it
contains only one type of atom.
OCompound – is a substance that is made
from two or more simpler substances is
either elements or other compounds. It
always contains two or more elements
joined in a fixed proportion.

28. 2. Mixtures, its properties can vary
because the composition of a mixture
is not fixed.
OHeterogeneous Mixtures – comes from
the Greek hetero and genus, meaning
“different” and “kind”. The parts of the
mixture are noticeably different from one
another.
OHomogeneous Mixtures – the
substances are so evenly distributed that it
is difficult to distinguish one substance in
the mixture from one another. It appears to
contain only one substance.

29. Based on the size of its largest
particles, a mixture can be classified as
a:
OSolutions– when substances dissolve and
form a homogenous mixture. Ex. Sugar &
water
OSuspension – is a heterogeneous mixture
that separates into layers over time. Ex. Sand
& water
OColloid – contains some particles that are
intermediate in size between the small
particles in a solution and the larger particles
in a suspension. Ex. Jellyace, chalk

30. Properties of Matter
1. Physical Properties
2. Chemical Properties

31. Physical Properties
-– is any characteristic of a material that can be observed or
measured without changing the composition of the substance in
the material.
Examples of Physical Properties
a. Viscosity – the tendency of a liquid to keep from flowing or its
resistance to flowing. The greater the viscosity, the slower the
liquid moves such as thick liquid (corn syrup, honey)
b. Conductivity – a material’s ability to allow heat to flow. Ex.
Metals
c. Malleability – is the ability of a solid to be hammered without
shattering. Ex. Gold and metal
d. Hardness – one way to compare the hardness of two
materials is to see which of the materials can scratch the
other.
e. Melting and Boiling Points – the temperature at which a
substance changes from solid to liquid is its melting point. The
temperature at which a substance boils is its boiling point
f. Density – can be used to test the purity of a substance.

32. Using Physical Properties
1. Using properties to identify Materials
2. Using properties to choose materials
3. Using properties to separate
mixtures
OFiltration- is the process that separates
materials based on the size of their
particles.
ODistillation – is a process that
separates the substances in a solution
based on their boiling points

33. Recognizing Physical Change
OPhysical change occurs when
some of the properties of a material
change, but the substances in the
material remain the same.
Ex. slicing a tomato
Crumpling a piece of paper
Slowly heat butter in a pan

34. Chemical Properties
--– any ability to produce a change in the composition
of matter. It can be observed only when the
substances in a sample of matter are changing into
different substances.
Examples of Chemical Properties
O Flammability – is a material’s ability to burn in the
presence of oxygen.
O Reactivity – the property that describes how readily
a substance combines chemically with other
substances.

35. Recognizing Chemical Change
Chemical Change occurs when a substance reacts
and forms one or more new substances.
O Three common types of evidence for Chemical
change
 A Change in Color
Ex. Banana ripens; match burn
 Production of a Gas
Ex. when you mix vinegar with baking soda, bubbles of
carbon dioxide form immediately
 Formation of a Precipitate – any solid that forms and
separates from a liquid mixture.
Ex. The curds in cottage cheese form when an acid is
added to milk

36. States of Matter
OSolid – materials have definite shape and
a definite volume.
OLiquid – materials has a definite volume
but not a definite shape.
OGas – material has neither a definite shape
nor a definite volume.

37. ASSESSMENT
(Reviewing Content)

38. Question
OWhich of these substances is not an
element?
a. Water
b. Aluminium
c. Hydrogen
d. Iron
e. Nitrogen

39. Question
OTap water is
a. An element
b. A substance
c. A compound
d. A mixture
e. A colloid

40. Question
OWhich action involves a chemical
change
a. Making ice cubes
b. Adding sugar to tea
c. Cutting wrapping paper
d. Baking a cake

41. Question
OAll pure substances
a. Contain only one type of atom
b. Can be broken down into simpler
substances
c. Cannot be broken down into simpler
substance
d. Have a fixed composition
e. Have a variable composition

42. Question
OWhich property can be used to
separate a mixture by distillation
a. Melting point
b. Boiling point
c. Density
d. Viscosity
e. conductivity

43. Question
OYou can be certain that a change is a
chemical change if
a. The change cannot be reversed
b. New substances form
c. Bubbles are produced
d. A precipitate forms
e. There is a color change

44. Question
OA beaker containing a black-yellow powder
has a magnet put into it. When the magnet
is removed, black particles are stuck to it,
leaving a yellow powder behind in the
beaker. The black-yellow powder is
therefore
a. A mixture
b. A compound
c. An atom
d. An element

45. Question
OKarl poured some vinegar into a bottle. He
added some baking soda and covered the
mouth of the bottle with a balloon. After
some time the balloon inflated. What
causes the balloon to inflate?
a. Formation of milky substance
b. Formation of precipitate
c. Evolution of CO2
d. Combination of two substances

46. Question
O Refer to the table below:
Chemical
System
Mixed
Substances
Observation Results
A Sugar + water Some sugar articles remain
undissolved
B Sugar + hot water All sugar particles dissolved in
hot water
C Egg shells +
vinegar
Bubbles moving up to the
liquid’s surface
D Milk + lemon juice White gelatinous solid
suspended in liquid

47. Question
OYou need 10ml of water in an activity, if all
the given measuring instruments are
available, which do you have to use to
measure the water.
a. 25 ml beaker
b. 50 ml beaker
c. 25 ml graduated cylinder
d. 50 ml graduated cylinder

48. Question
OMixtures that are being stirred dissolve
faster than mixtures that are not
stirred. Which of the following factors
can explain it?
a. Exposed surface area
b. Kind of solvent
c. Size of the solute particles
d. Temperature due to stirring

49. Question
OWhen you see bubbles on the bowl of soup
which had been left on the table for one
night, you may infer that:
a. The liquid component of the soup is
evaporating
b. Physical change is taking place in the soup
c. The soup is undergoing chemical change
d. Air is dissolved in the soup

50. PHYSICS
Force
s ENERG
Y
MOTIO
N

51. MOTION
Motion
Displacemen
t
Acceleration
Velocity
Distance
Direction of Movement
Speed
Direction of
Motion
 Change in Speed
 Changes in Direction
 Changes in Speed &
Direction

52. Distance & Displacement
ODistance is the length of the path
between two points.
ODisplacement is the direction from
the starting point and the length of a
straight line from the starting pint to
the ending point.

53. SPEED AND VELOCITY
O Speed is a scalar quantity that refers to "how fast
an object is moving."
O Velocity is a vector quantity that refers to "the rate
at which an object changes its position.“
O FORMULA:

54. Acceleration
----can be described as changes in speed,
changes in direction, or changes in both. It is
a vector.
FORMULA:
a=
𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦
𝑇𝑜𝑡𝑎𝑙 𝑇𝑖𝑚𝑒
=
𝑉 𝑓−𝑉 𝑖
𝑡

55. FORCE
O A force is a push or pull upon an object resulting
from the object's interaction with another object.
O Formula: F= mass x acceleration
Two broad categories:
1. Contact forces are those types of forces that
result when the two interacting objects are
perceived to be physically contacting each other.
2. Action-at-a-distance forces are those types of
forces that result even when the two interacting
objects are not in physical contact with each
other, yet are able to exert a push or pull despite
their physical separation

56. TYPES OF FORCE
Applied Force An applied force is a force that is applied to
an object by a person or another object.
Gravity Force
(also known as
Weight)
The force of gravity is the force with which the
earth, moon, or other massively large object
attracts another object towards itself.
Normal Force The normal force is the support force
exerted upon an object that is in contact with
another stable object.
Friction Force A force that opposes the motion of objects
that touch as they move past each other.

57. FRICTION
OFOUR MAIN TYPES OF FRICTION
1. Static Friction – is the friction force that acts on
objects that are not moving.
2. Sliding Friction – force that opposes the
direction of motion of an object as it slides over
a surface.
3. Rolling Friction – force that acts on rolling
objects.
4. Fluid Friction – opposes the motion of an object
through a fluid

58. ENERGY
----is the ability to do work.
FORMS OF ENERGY
MRS CHEN

59. 1. MECHANICAL ENERGY
Mechanical energy ---- is the energy that
is possessed by an object due to its
motion or due to its position.
OIt can be either
1. kinetic energy - energy of motion
2. potential energy - stored energy of
position

60. 2. Radiant energy is the energy
of electromagnetic waves. It is a
form of energy that can travel
through space.
3. Solar Energy is the energy
from the sun.
4. Chemical Energy – is the
energy that results during a
chemical reaction.

61. 5. Heat Energy is the energy
that comes from heat.
6. Nuclear energy refers to the
process of using nuclear
processes in order to generate
heat or electricity.

62. Newton’s Law of Motion
NEWTON’S FIRST LAW OF MOTION
“The state of motion of an object does not
change as long as the net force acting on the
object is zero.”
NEWTON’S SECOND LAW OF MOTION
“The acceleration of an object is equal to the net
force acting on it divided by the object’s mass.”
a=
𝑵𝒆𝒕 𝑭𝒐𝒓𝒄𝒆
𝑴𝒂𝒔𝒔
=
𝑭
𝒎

63. NEWTON’S THIRD LAW
“Whenever one object exerts a force on a
second object exerts an equal and opposite
force on the first object.

64. Energy Conversion
----Energy can be converted from one form to
another.
Ex. The striking of the match.
Chemical Energy Kinetic energy thermal
energy

65. ASSESSMENT
(Reviewing Content)

66. Question
Rody kicks a ball on a level sidewalk. It
rolls to stop after sometime
because____
a. No force is acting on the ball
b. Inertia at rest is acting on the ball
c. Gravity pulls the ball down
d. Friction slows the ball down

67. Question
Bikers apply grease to the gears
of bicycle to___
a. Reduce friction
b. Increase acceleration
c. Avoid accident
d. Facilitate easy turn in the curve

68. Question
A taxi and a truck are travelling in the
same direction at the same speed.
Why would the car accelerate faster
than the truck.
a. The taxi has less mass
b. The taxi has less force
c. The taxi has new engine
d. The taxi has more gasoline

69. Question
Which energy conversion is true
for a battery operating toy car?
a. Electrical - mechanical - sound
energy
b. Chemical – mechanical-sound
c. Electrical-mechanical-sound
d. Sound-electrical-mechanical

70. Question
If you blow up a balloon, and then
release it, the balloon will fly away.
This is an illustration of_____
a. Newton’s First Law
b. Newton’s second Law
c. Newton’s Third Law
d. None of the above

71. Question
Yaya Dub placed a thick curtain on the
window during summer to minimize the
entrance of heat. Which type of heat
transfer did she consider?
a. Conduction
b. Convection
c. Radiation
d. Filtration

72. Question
A car moves at a constant speed of
25m/s. this means that the car:
a. Increase its speed by 25 m/s every
second
b. Decreases its speed by 25 m/s
every second
c. Moves 25 meters every second
d. Doesn’t move

73. Question
The acceleration due to gravity is lower
on the moon than on Earth. Which of the
following is true about the mass and
weight of an astronaut on the Moon’s
surface, compared to Earth?
a. Mass is less, weight is same
b. Mass is same, weight is less
c. Both mass and weight are the same
d. Both mass and weight are less

74. Question
Ali threw a ball over the fence.
What energy did the moving ball
have?
a. Heat energy
b. Potential energy
c. Light energy
d. Kinetic energy

75. Question
A jeep is travelling in a highway at a
speed of 100 km/h. suddenly, the driver
stepped on the brakes. In what direction
will the sitting passengers be thrown
when the jeep suddenly stops?
a. Forward
b. Backward
c. Sideward left
d. Sideward right

76. Question
Which of the following is not an
example of kinetic energy being
converted to potential energy?
a. Releasing of arrow
b. Pulling a plod in the rice field
c. Releasing of compressed spring
d. Basketball player jumping for a
rebound

77. Question
which of the following situations illustrates
the direct transformation of potential to
kinetic?
a. A tank is being filled with water
b. An arrow is released from a bow
c. The driver steps on the brakes of his
car
d. The spring of a mechanical toy car is
being turned

78. Question
The following situations show that work is
done on an object other than oneself
EXCEPT in
a. Carrying a 50N laptop to a distance of
100m
b. Going up a flight of stairs with a
backpack
c. Lifting a bag of grocery up a jeep
d. Pushing a table across the room