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2 Energy is something that is needed to make things happen. Energy can make things move or change. Energy is not a substance or an object that you can touch or hold.

3 Riding a motorbike Mowing the lawns The wind to blow Lighting a candle Parachuting Running Using a computer Energy makes things happen

4 The Law of Energy Conservation Has three parts: Part 1 = “Energy must come from somewhere. It is never created out of nothing”

5 In fact, most energy can be traced back to nuclear reactions inside the sun which transforms stored energy in matter to heat and light energy.

6 Part 2 = “Energy may change form but the amount stays the same”

7 Part 3 = “Energy can never be destroyed, only transformed” Most energy ends up as heat energy.

8 The whole law = “Energy is never created or destroyed, and the total amount of energy always remains the same”. A scientific law states what will always happen.

9 Forms of Energy Light - Travels at 300,000km/s

10 Sound -Made by vibrating objects - travel at 330m/s through air

11 Heat -Affects the movement of particles. -The more energy, the faster they go and the higher the temperature

12 Gravitational potential -is found in objects that can fall -The further the object can fall the more GPE it has. i.e. Bart

13 Nuclear potential -Stored in the nucleus of an atom -Can release huge amounts of heat, light and radiation.

14 Kinetic -the energy of a moving object -The faster or heavier an object is the more kinetic energy it has.

15 Electrical - The flow of energy as charged particles called electrons move along a conductor.

16 Magnetic potential - The energy of some metal objects in a magnetic field.

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18 Elastic potential - Found in objects that have been stretched or squashed and are able to regain their original shape when released

19 Chemical potential -Energy stored in the bonds between atoms -i.e. food and fuel

20 Active Energy are those types of energy that can be seen to change from one type to another, i.e. you see two types of energy. Examples include fireworks and avalanches.

21 Active Energy Types Light Sound Kinetic Heat Electrical

22 Potential Energy is also called stored energy because it has the potential to do something.

23 Potential Energy Types Gravitational Elastic Nuclear Chemical Magnetic

24 Energy Transfer Energy can be passed from one object to another. The transfer of energy does not change the type of energy. For example, eating food moves chemical energy from the food to you.

25 When a room is heated all objects in that room warm up (gain heat) to the same temperature.

26 Energy Transformations occur when energy changes from one type to another. A microphone transforms sound energy into electrical energy.

27 A washing machine transforms electrical energy to kinetic, sound, heat and light energy

28 The light, sound and heat energies from this projector came from electrical energy in the wiring which came from the water falling through a turbine at a power station which came from rain falling from the sky

29 which came from evaporation caused by the heat of the sun which came from nuclear reactions in the sun’s atoms ….

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32 This can be summarised as: Nuclear  Heat  Gravitational  Gravitational  Kinetic  Electrical  Heat + light + sound

33 What are the energy transformations in this battery-powered toy car? Chemical potential energy in battery  Electrical energy in wiring  Kinetic energy of propellor  Kinetic energy of car

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35 Measuring Energy Energy is measured in joules and is given the symbol J. Heating 1mL of water by 1°C requires 4.2 joules of heat energy. Lifting 1kg up by 1m requires 10J of energy.

36 1kilojoule = 1000 joules 1kJ = 1000J

37 Wasting Energy Some of the energy in a transformation is unable to be used. For example, the heat produced by a TV does not make the light or sound any better. It is wasted

38 Energy = useful + wasted input energy energy The useful energy is the type that does what you want. The waste energy is the type that you cannot use.

39 Energy Efficiency Designers try to produce appliances that make as little waste energy and as much useful energy as possible. Energy = useful energy x 100 EfficiencyEnergy input

40 Food Energy Our bodies require energy to keep us active and alive. This energy comes from our food and drink. Our bodies are also designed to store energy in case we cannot get food.

41 This was very useful for our ancestors when food was not always available e.g. 10,000 years ago and earlier. We have not lost this ability and store the extra energy as fat.

42 Our bodies use energy which needs to be replaced. If we don’t get enough energy we become tired and sick. But, if we get more energy than our bodies use we can become obese (fat). Some people are obese because of medical reasons unrelated to their diet.

43 Therefore we need to eat a balanced diet, i.e. one that contains all the needed nutrients but also one that has just enough energy to keep us going but not too much that we become fat.

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46 Exercise uses energy that can reduce the amount of stored fat.

47 Energy Sources People require huge amounts of energy to keep cities going. The most common form used is electrical energy. This energy comes from a range of different types of power plants.

48 Some power plants use non- renewable sources of fuel. These include power stations that burn coal,

49 oil or gas. One day we will run out of these fossil fuels.

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53 Other power plants use renewable sources of fuel. These include hydro power stations (dams),

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55 and solar panels. We will never run out of these energy sources.