Homes and schools work on electricity



In the home electrical energy is changed into light, heat, movement and sound. There are a range of devices which change electrical energy into other forms of energy. You can see some of them in this picture. There are also some ways of getting electricity into the home. Move the cursor over the diagram and click when the hand appears to find out more about these features.

When was electricity discovered?
The power of electricity was discovered about 2500 years ago in Greece. A man called Thales was a teacher who was interested in the world around him and noticed that when a yellow material called amber was rubbed against a cloth - pieces of straw and dust stuck to it. The Greek name for amber was 'elektron', meaning 'the power in amber'. The Greeks, of course, did not know that this power was electricity. However, we still find the word elektron in our word electricity.

Is the electricity in amber like that flowing through a wire?
No. There are two kinds of electricity. They are called static electricity and Static stays put on the surface of insulating materials like amber or plastic. Current electricity moves about, in metals, for example, flowing through wires. Current electricity is the kind of electricity we get through plugs in walls and from.
Is static electricity useless?
Static electricity is usually a problem to us. It is the cause of dust sticking to the surfaces of plastic, for example. It can even make hair stand on end!



Can static electricity move?
Yes. Sometimes the build-up of static electricity is very high. When this happens the electricity escapes into the air as a spark or a flash. When you take off a pullover which has nylon in it, for example, the threads rub together and become charged with static electricity. There is so much electricity that it leaps through the air from one part of the cloth to another. When this happens a tiny spark is made which makes a small crackling sound. Lightning is a huge spark. It occurs when storm clouds build up huge amounts of static electricity.

How is a current of electricity made?
It is made in two ways. It can be made by a battery or by a generator in a power station.

A battery contains chemicals. When you switch on something that uses batteries the chemicals in the battery change. This change makes a current of electricity flow. It may light a lamp, turn a motor or sound a buzzer.


A generator contains a very large magnet inside a huge coil of wire. When the magnet turns it makes a current of electricity in the coil of wire. The current is made to flow along cables to the mains in your home and school.

Is the current from a battery and a power station the same?
No. The electricity from a battery is much weaker than the current from a power station. This is why you can do investigations with batteries. The electricity from a power station is so strong that it can kill you. That is why you must always take great care using mains electricity.

Why is the electricity from a power station so powerful?
It has to be powerful to make lights shine brightly and provide power for everything we need at home, at school, in offices and factories.