1. Using energy Ch 5
5.1 – page 171

2. Ch 5.1 Energy around you What do you already know about energy?
Create a mind map for ENERGY – list your answers on separate subtitles on the map
list 3 types of energy
3 devices that use energy
Explain – energy efficient
Define energy
Origin of most energy on planet earth

3. Teacher resources – Exps for Ch 5.1
Spider – p 171
Creepy Crawly – p 173
Spinning snake – p 177
Energy sample p 178 – need 3 extras for 8 stations.

4. What does energy do?
Energy is invisible, but you can see what energy does – sound, heat, movement, light. Energy makes things happen.
Work – is the name given to the effects of energy. When you use energy, then work is done.
Measuring energy = joule (J). One Joule is the energy required to lift 1 kg of potatoes 10 cm.
I kilojoule = 1000 joules will lift the potatoes 100 m
I megajoule = 1,000,000 joules

7. How far would you have to carry 1kg of potatoes to use up one serve of this food?
Given that 1kJ (x 1kg) = 100m.
Therefore 459 kJ would equal 459 x 100m,
or 45.9 x 1000 m = 45.9 km
Better not to eat it then to try and run it off??

8. Forms of energy Kinetic – movement (anything moving).
Heat – from the sun, flames, electrical, chemical or animals.
Light – sun, light bulbs, glow worms, phosphorus in the ocean
Sound – vibrating air particles – guitar, voice, device
Electrical – power stations, batteries, photovoltaic cells, generators
Page 172 Interactive – Forms of energy review – drag and drop.

9. Stored energy – potential energy
Some energy is stored (has the potential to do work when required)
Chemical potential energy – energy from the sun is converted to chemical energy in plants by the process called photosynthesis. Food, petrol and batteries contain this form of energy.
Gravitational potential energy – is the energy stored due to an object’s height above the ground – water in a hydroelectric dam, the top of a water slide
Elastic potential energy – stored in squashed springs and elastic bands.
Nuclear potential energy – energy that is released by nuclear reactions/explosions.
Hero of the Hudson – worksheet from page S:\Science\8 Science\Ch 5 Energy
Unit Review Questions 1-16 from page

10. Review Questions
1 The joule (J) is the unit for measuring energy.
2 Students could state any five from: kinetic, sound, heat, electrical, light, nuclear, gravitational potential, chemical, elastic potential.
3 a kinetic energy: in a moving object
b sound energy: in vibrating air particles
c elastic potential energy: in a stretched or squashed spring
d gravitational potential energy: in objects positioned above the ground
e light energy: released from glow-worms
4 The energy in food is usually stated in kilojoules rather than joules because one joule is a very small amount of energy.
5 Sound is produced by a vibrating object, such as the string of a guitar or the prong of a tuning fork. In this way, sound is a form of kinetic energy.

11. Ch 5.1 6-10 Petrol, kerosene and oil all possess chemical energy.
Student answers. Some examples are: car crashing into an object, a golf ball hitting a tree, the effects of a cyclone, two people running and crashing into each other, tripping over while running.
a 3 megajoules = 3 × J = J
b kilojoules = 7500 × 1000 J = J
a joules ÷ = 2.5 megajoules
b kilojoules = × 1000 J = J = 5 MJ
a chemical energy
b elastic potential energy

12. 11 Chemical energy from food can be used by your body to produce:
• growth (forming new molecules and storing energy)
• sound energy (talking, singing)
• kinetic energy (movement)
• heat energy (body warmth)
12 a heat energy
b kinetic energy
c chemical energy
d kinetic energy
e chemical energy
f gravitational potential energy

13. a Dancing for an hour, Ben uses: 30 kJ × 60 = 1800 kJ of energy.
b One serving of this cereal with whole milk has an energy content of 930 kJ. This means Ben would need to eat almost two serves to supply the energy for his hour of dancing.
c When Ben dances, kinetic energy, sound energy and heat energy are present.

14. 14 Note that it is assumed that all objects are on the ground except where specifically stated otherwise.
a chemical
b elastic potential
c chemical
d gravitational
e chemical
f chemical
g chemical
h gravitational
i chemical
j elastic

15. 15 Many correct answers are possible, as long as the mass lifted (in kilograms) multiplied by the height lifted (in centimetres) equals 100.
Two examples are: She could lift a 20 kg bag of onions 5 cm off the ground. She could lift a 5 kg bag 20 cm. 16
i Glass A, ball A and car A all have more energy than their pair.
ii Each glass has the same amount of water, but glass A is hotter and so has more heat energy. Ball A has more energy than ball B because it is higher and so has more gravitational potential energy. Car A has more

16. Spinning Snake

17. Energy does work

18. Ch 5.2 Energy changes Teacher Resources
S:\Science\8 Science\Ch 5 Energy – PhET
Ch 5.1 and 5.2 Energy- quizlet
PhET - Energy simulation
Dominoes – p 179
Heat Transfer – p 180 Iron rods and Bunsen burner
Untamed Science – p 180
Hot stuff – p 182 Friction and heat
Renewable Energy video – p 184
Prac Investigating Heat – p 187
Prac Energy Changes – p 188
Review – Q 1-20 p 185-6

19. Energy Transfer – same type of energy
Energy can be passed from one object to another – this is called Energy Transfer
heating up in front of a fire – heat is passed to your skin
kicking a ball – kinetic energy from your foot goes to the ball.

20. Energy Transformation – to a different type of energy
Toaster – electrical to heat
iPod – chemical – electrical – heat, sound and light
Wind up toy - elastic potential – kinetic, sound
Car - chemical – kinetic, sound
Untamed Science – p 180

21. Create an energy flow chart – label each type of energy.

22. The Law of Conservation of Energy
The Law of Conservation of Energy – energy can never be created nor destroyed – it can only be converted from one type to the other. This means it can be transferred or wasted as heat, usually the heat is transferred to another object, but never disappears. Untamed Science – p 180

23. Useful and wasted energy

24. Energy Efficiency
Energy efficiency is the measure of how much useful energy is converted for the original purpose and how much energy is wasted – usually as heat or noise.

25. p 184 Create a flow chart of the energy transformations
Renewable Energy video p 183

26. S:\Science\Middle School (7-9)\8 Science\2014\Ch 5 Energy

28. Review of Ch 5.2 P 185 Q 1-20 Prac 5.2.1 Investigating Heat
Prac Energy changes