Background Information 

Electricity can flow, or is 
conducted, through some 
things more easily than
others. How well a wire
conducts electricity is
measured by the wire’s
resistance. The resistance
depends on what material
the wire is made of, the
length of the wire, and the
thickness of the wire. The
lower the resistance of the
wire, the better it conducts
electricity.

Electric current is created by
a flow of tiny particles called
electrons. As the electrons 
move through a wire, they
can slow down and lose
energy. The electrons in
some materials do not move
easily. 

These materials have a 
higher  resistance than
materials in which electrons 
can move easily. The longer
and narrower the wire, the 
harder it is for electrons to
move through the wire, and 
the greater the wire’s 
resistance.