Electricity is an extremely useful form of energy. It can easily be changed into other forms of energy, such as light, heat and sound energy. Current electricity is easy to use because it can be sent along wires to wherever it is needed.

What is electricity?

Electricity is a kind of energy stored inside atoms, the tiny building blocks of all things. Atoms themselves are made up of particles. These include electrons, which have a negative electric charge, and protons, which have a positive electric charge.

Static electricity

Static electricity is a kind of electricity in which the electrons do not move. It is produced when two objects rub against each other. The electrons rub off from the atoms of one material on to the other.

​​​​​​​You can make static electricity by running a comb through your hair. The comb leaves a few of its electrons behind in the hair, so the comb now has a small positive charge. It can pick up small pieces of paper because it attracts the electrons in the paper’s atoms. If you comb your hair in a dark room then hold the comb close to your thumb, you will see a tiny spark. The release of electricity heats the air molecules (groups of atoms) between comb and thumb, producing a flash of light.

An electric charge heating air molecules is exactly what happens—but on a much grander scale—when lightning strikes during a thunderstorm. Lightning is static electricity that suddenly leaps between clouds and the ground. Thunder is the noise of the air expanding rapidly in the intense heat.

Electrons flow through a conducting wire when it is connected to a battery or generator. When the current is switched on, the electrons all move in the same direction. They flow only if they have a complete pathway of conductors called a circuit. Electric current is measured in amperes (amps). This is the rate at which electricity flows through a conductor.

Power stations

The electricity in your home comes from a power station. Most power stations burn fuels, such as coal or oil. The heat drives a turbine, a large bladed wheel. This is connected to a machine called a generator, which converts the spinning movement of the turbine into electricity.

The electricity flows along underground cables, or cables held above the ground by pylons, and into your home. There it is turned into other forms of energy, such as light, sound and heat, or to power televisions, washing machines and other household appliances.

The force with which an electric current is pushed along is measured in volts. Power lines carry electricity at a high voltage. At substations, the voltage is made lower so the electricity can be used in the home.

Alternative fuels

Instead of burning coal or oil in power stations, electricity can be produced by other means. A generator can be powered using running water or the wind. Nuclear power stations use the energy released when atoms are split apart. Solar panels turn sunlight into electricity.

Hydro-electric power

Hydro-electric power stations use fast-flowing water to make turbines spin round. The water from rivers is stored in a reservoir behind a dam, a large barrier. Water released from the reservoir rushes past the blades of a turbine installed inside the dam.