Energy is all around us. But where does it come from, and where does it go? Find out here …

So where does energy come from?
The sun is the main source of energy for the Earth. If you think about all of the energy resources we use, you’ll find they all trace back to the sun. Fossil fuels, like coal and oil, were once plants and animals that originally received energy from the sun for photosynthesis and food. Even wave power is ultimately caused by changes in heat from the sun. We rely on the sun for light and heat, but despite its size and strength, it cannot possibly burn at the rate it does forever. It is believed that the sun is about six or seven billion years old, and will probably live and burn for a further six or seven billion years. Good news – it should still be burning in your lifetime!

Where does energy go when you use it? The truth is, energy is never really ‘used’; it is just changed into another form of energy. So, when a kettle is boiling, it is not really ‘using’ energy, but actually turning electrical energy into heat energy.

Launch it ... Have a look at the Human Cannonball and see how energy is converted when the Human Cannonball is propelled over the canyon!
Did you know ... ?

There are two types of energy: stored energy (or potential energy) and working energy (kinetic energy). Can you identify which type of energy a boiling kettle has?

Energy comes in many different forms. How many can you think of? There’s heat (thermal), light (radiant), mechanical, electrical, chemical and nuclear energy.

Launch it ... Test your energy know-how in this memory game. Can you find the energy pairs?

Perpetual motion is something that defies the usual laws of physics. That sounds pretty impressive, and it is! Energy can’t be created or destroyed, but some energy will unavoidably be ‘lost’ to friction. This means that usually, when something has energy, and the energy it has is in motion, it will eventually stop moving because the energy has been ‘lost’ through friction and changed into something else. Where something is described as being in perpetual motion, it means that once it has been started it can work without ever stopping. The energy simply doesn’t ‘run out’, but instead keeps working at the same level forever.

Unfortunately, no one has ever managed to create perpetual motion. If they had, it would be incredibly useful. Imagine the effect it would have on our transport! Which other things in our daily lives would it improve?

Discuss it ... What would you use perpetual motion for if you created it?
Teachers' Notes ... For Teachers' Notes on this subject, click here