Every form of energy can change into another form of energy.
Coal is a fuel that contains stored chemical energy. When coal burns, the chemical energy inside it changes into heat energy.
Energy may change in form, but it can’t be made out of nothing, and neither can it be destroyed.
A power station does not create the electrical energy we use in our homes.
The power station changes the chemical energy of the fuel into electrical energy.
 When we use electricity, we don’t destroy the electrical energy. Instead, we change this energy into another form of energy, such as heat or light.

Energy converters

Imagine you are on a camping trip. You feel tired at the end of the day and want a hot drink. You’ve taken with you some soup and matches. You’ve also brought an aluminum saucepan. Woods nearby supply you with dry twigs.

When you make a camp fire, heat the saucepan, and drink your soup, a scientific process takes place. By setting fire to the wood, you change, or convert, the stored chemical energy in the twigs into heat energy. This heat energy boils the soup. After you have drunk the soup, your body turns the chemical energy in the soup into potential energy. Your body will turn it into kinetic energy for use on the camping trip.

Your body is an energy converter. Some of the chemical energy you take in as food is converted into potential energy and then into kinetic energy. Some of the chemical energy is converted into heat energy to maintain body temperature.

Converting energy in the home

We need to change one kind of energy into another in our homes. A toaster changes electrical energy into heat energy. An electric light bulb converts electrical energy into heat and light energy. If you look around your house, you’ll soon realize there are a number of energy converters at home.

The solar cells on this light aircraft convert the sun’s rays into electricity.

Old and new energy converters

For thousands of years, people have made many different kinds of energy converters. One of the earliest kinds was the waterwheel.

Moving water pushed the blades attached to the wheel, and this made the wheel turn. Waterwheels were often joined to large millstones. As the waterwheel turned, it turned the millstones, which then ground corn or wheat. The waterwheel converted the potential energy of the falling water into kinetic energy for grinding the foodstuff.
A solar cell is a modern kind of energy converter. It converts light energy from the sun into electrical energy. Solar cells can be used to make radios and telephones work. Solar cells are also used to operate telecommunications satellites which orbit the earth.