Electric circuits
Electricity follows a path. The path that an electrical current follows is called an electric circuit. An electric circuit can be closed or open.

• A closed circuit is a complete path for electricity to move along. When a switch is closed a circuit is closed and electricity can move through the circuit.
• An open circuit is an incomplete path that electricity cannot move along. No electricity can move anywhere in the circuit. When a wire is broken, the circuit is open and the electricity cannot move through the circuit.

Different buildings and electrical equipment have separate circuits; the flow of electricity can be cut off or changed through switches, usually at the beginning and end of circuits.

What does a circuit look like? At the left is a sample diagram of circuits. Lines and arrows indicate the direction and flow of electricity.

Where examples of circuits can be found.
Circuits are found in many places throughout the world. In your home, for example, separate circuits are established to control specific devices and appliances. Circuits are present throughout the community.

Local electricity companies establish circuits to send specific amounts of electricity to certain regions.

Circuits can also be found on moving objects. Electrical circuits can be found in cars, planes, and other forms of transportation that use electrical energy. Toys can also have electrical circuits; any battery powered toy has electrical circuits.

Series circuits
In series circuits there is only one path for the electricity to follow. Whenever one thing in a series circuit stops working, everything in the circuit stops working. The electricity cannot get past the open part of the circuit. Series circuits are mostly used for one bell, or one light bulb, or one motor. Christmas lights are often wired in a series...if one goes out, all the lights go out.

Two batteries in a series (Sixth Grade project).	Schematic of two light bulbs in a series (Sixth grade project).

Parallel circuits

A circuit the has more than one path for the electrical current to follow is called a parallel circuit. Each room in a building may be part of a large parallel circuit. All the lights in a room are separate parts of the circuit. The electrical current has many different paths to follow. If one part of the circuit is open, the rest stay closed. If one light bulb burns out, the rest stay lit.

Bulbs in parallel circuit (Sixth grade project).	Schematic of two bulbs in parallel circuit (Sixth grade project).

If you need more information about electrical circuits and electricity in general, connect to the WWW link : http://www.ibiblio.org/kuphaldt/ for a very complete lesson on electric circuits.