What is energy? Energy is the ability to do work. It's what you get when you burn fuel (= stored energy) to move something like a car or kick a ball (= do work). That fuel can be stuff like coal or gas or the hydrogen which powers the sun. What you get is heat and light energy. You can feel the heat from a fire or from the sun on your skin. And sunlight makes our daytime.

	Energy can be changed from one form to another but it can't be created or destroyed.

People have learned to use stored energy to do useful work for them. By burning coal, you can use the chemical energy stored in the coal to heat up water until it becomes steam which then drives large machines to generate electricity. Electricity is another form of energy and it too can be made to do useful work, like running your washing machine or powering your computer and mp3 player. But electricity doesn't have to be made by burning coal. It can be made from renewable energy sources like wind and water power. It can also be made by nuclear power, yet another source of energy. Whichever way electricity is made, it's changing one form of energy to another.

	Types of Energy Potential energy is stored in a body and has the potential to do work. There are four types: Chemical: energy stored in things like the food you eat, fossil fuels and explosives Elastic: energy stored in a stretched elastic band or spring, for example Gravitational: the energy a body has because it's near to another large body, like a planet. If a big hole opened up under you, you'd be pulled (fall) down it because of the pull (= energy) of Earth's gravity Nuclear: energy stored in the nucleus of atoms. This energy is used in nuclear power stations to generate heat. The Sun and all the other stars shine because of the energy released when atomic nuclei split or fuse together There are many different types of energy but they're really all variations of one (or some) of these: Heat: if you touch something hot, it can be very painful as that heat flows into you Kinetic: this is the energy which a moving body has. If someone kicks a ball hard and it hits you, it hurts because your body has had to suddenly absorb all that energy and stop the ball Electrical: this is the kinetic energy of moving charges in an electrical circuit. One example is electricity flowing through a light bulb. It makes both heat and light by passing through a resistance (the light bulb's filament) Electromagnetic: light and other radiation are all forms of electromagnetic energy I used a lot of energy writing this! Now what sort of energyWhat sort of energy?Well it's not nuclear, is it? I'm not a nuclear penguin! Could it be kinetic do you you think? would that be...?

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