In this topic you will learn about some of the sources of electricity and the path electricity follows.

A cell is a source of electricity. If a bulb, wire, and cell are put together in the correct way, the bulb will light. Together they form a system. A system is a group of things that work together. The bulb, wire, and cell work as an electrical system. The system uses electric energy to light the bulb.

Electricity is a form of energy that travels in a circuit. A circuit is the path through which electricity flows. A circuit is like a train track. Just as the track must be complete before a train can travel on it, a circuit must be complete for electricity to flow. A complete circuit is called closed circuit. A closed circuit has no gaps. An open circuit has a gap. Electricity cannot flow through an open circuit.

You can control the flow of electricity. When you want to turn on a flashlight, you use a switch. A switch opens or closes an electric circuit. Pushing the switch one way closes the circuit. It allows electricity to flow in a complete path. The bulb lights up.

You use electricity at home. Almost everyone uses electric lights. You may also use electricity to heat your home. Electric machines include refrigerators, hair dryers, and vacuum cleaners. Radios, computers, and television sets all run on electricity.

In a toaster, electricity changes to heat as it flows through a wire. Electricity flows through an electric motor in a fan, causing the fan's blades to turn. Electricity makes a thin wire in a light bulb so hot that it glows.