South African Junior College School
Science Formal Test Answers
Grade 7
Energy [60]
4 September 2013
Instructions:
Write answers in pen. (Diagrams in Pencil and Colour)
Answer all questions on Exam Pad.
Write in full sentences where needed.
Rule off after every question.
Staple this question sheet to the back of your answer sheet.
Questions with a text box and a
are there to show you how to set out the work.
Question 1: The following definitions are all false. Change the bold word to make the sentence true. Write
the number and changed words only.
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
Fuel 
Energy 
Biomass 
Gravitational Potential Energy 
Joules 
Elastic Potential Energy 
Waves 
Thermal Energy 
Radiation 
Sulphur Dioxide 
[10]
Question 2: What is energy?
2.1
Which of the following is a conversion from chemical energy to thermal energy?
A.) Coal is burned to boil water.
C.) Charcoal is burned in a barbeque pit
B.) Food is digested and used to
regulate body temperature.
D.) All of the above. 
2.2
Which of the following is the best example of increasing an object's potential
energy?
A.) Rolling a bowling ball
C.) Stretching a rubber band 
B.) Turning on a light bulb
D.) Dropping a pencil
2.3
An object that has kinetic energy must be...
A.) lifted above earth's surface.
C.) at rest.
B.) in motion. 
D.) None of the above.
2.4
Thermal energy is...
A.) kinetic. 
B.) potential.
C.) both kinetic and potential.
D.) neither kinetic nor potential.
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2.5
Sound energy is...
A.) the energy of a compound that
changes as its atoms are rearranged to
form new compounds.
B.) the total energy of the particles that
make up an object.
C.) the energy caused by an object's
vibrations. 
D.) the energy of motion.
2.6
What device converts chemical energy to mechanical energy?
A.) Human
C.) Jet ski
B.) Car
D.) All of the above. 
2.7
As height increases, so does...
A.) thermal energy.
C.) kinetic energy.
B.) mechanical energy.
D.) potential energy. 
2.8
The law of _________________ of energy states that energy cannot be created or
destroyed.
A.) transformation
B.) absorption
C.) conservation 
D.) stability
2.9
According to the law of conservation of energy, in theory, a bouncy ball should
never stop bouncing. However, we know that it eventually stops. Where does the
energy go?
A.) Some gets converted into sound
B.) Some gets converted into thermal
energy and escapes into the surroundings. energy and escapes into the surroundings.
C.) Both A and B 
2.10
Energy is the measure of something’s ability to do work. Which of the following
has the most thermal energy?
A.) A dead battery
C.) Cup of coffee
B.) A melting Wakaberry™
D.) Swimming pool
[10]
Question 3: Energy sources (answers may vary, use discretion)
Nuclear Energy
a) This energy is used in nuclear power stations to convert water into steam. The steam is used to
drive turbines to generate electricity. This is done by splitting atoms with Uranium.
b) Advantages: Clean  Generates lots of power 
Disadvantages: Non-Renewable can be dangerous to dispose of. Any one
Biomass
a) These sources can be eaten and energy is passed though as food. These sources can be burned to
produce heat. These sources may be converted into other forms before they are used. Some are
fermented into alcohol that is uses in some petrol forms.  any two
b) Advantages: Renewable, Cheap 
Disadvantages: Takes up space, smells 
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Tidal Energy
a) A dam is built across the place where a river meets the sea. The dam fills up at high tide and then
empties at low tide. The movement of the water into and out of the dam turns turbines to make
electricity. 
b) Advantages: Renewable, Efficient
Disadvantages: Expensive
Solar Energy (water)
a) Using solar panels that contain water. This water is heated up by the sun and then it can be used
by the people in the house.
b) Advantages: Renewable, Efficient
Disadvantages: Expensive to set up
[10]
Question 4: Energy Transfers and Forms of Energy
4.1
Teacher check. Any two moving objects that are increasing in height
4.2
Many options here are some suggestions. Any one of these or others:
(2)
Light Energy - Gararge light, camera, cellphone, police torch
Kinetic – Lasoo, tree being pushed 
Sound – Man on phone, reporter
Thermal – any light source
Gravitational PE – Man in camera chair, boys on fence
Chemical PE – Fuel in car, food, huge doughnut 
Elastic PE – Trampoline 
Biomass – Tree 
Electrical – Cellphone, camera 
Solar – sun is out
(10 x ½ = 5 )
4.3.1 Teacher check if relevant. Make sure that they stated an independent and dependent variable as
well as how to keep it a fair test.

(5)
4.3.2
Teacher check
(3)
[15]

Question 5: Energy Transfer Diagrams
5.1
As the inventor moves his spoon, it triggers a dice to fly and hit a parrot.  The parrot will fly away
allowing a powder to be filled into a glass. As the glass gets heavier it pulls a string which lights a match.
The match sets off a rocket that cuts a rope. This allow the napkin to fall on his face. 
(4)
5.2
5.3
Chemical Energy
(Match)
Heat Energy
(Rochet fuse)
Kinetic Energy
(Rocket and
knife)
Any picture that represents the sequence. half a mark each change 
Kinetic Energy
(Napkin)
(2)
[10]
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Question 6: Heat Transfer
6.1
Conduction  – heat through metal rod 
Convection – Heat warms air and makes a current 

Radiation  - travels through waves
[5]
[Total Marks: 60]
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