Background Information 

Current electricity is created
by a flow of tiny particles 
called electrons. The electrons have to have a 
closed path to travel along. 
This path is called a circuit. A circuit usually has at least 
three parts: a source of 
electrical energy, such as a 
battery; a substance for the
electricity to travel in, such 
as wire; and something that 
uses the electricity, such as 
a light bulb.

A switch is used to open 
and close a circuit. When 
the circuit is closed, 
electricity can flow through
the circuit. When the circuit
is open, electricity cannot 
flow through the circuit.

Some circuits also contain 
devices called resistors. 
Resistors change how easily electrons can move 
through the circuit.

There are two types of 
circuits, series circuits and 
parallel circuits. In a series 
circuit, all the parts of the 
circuit are connected one 
after the other. The current
can follow only one path. In
a parallel circuit the parts are connected in different 
ways, so the electricity can 
follow more than one path.