Spark image
Electric current

Solids conduct electricity because they contain tiny negatively charged particles called ELECTRONS that can move around in them.
In metals some of the electrons (called FREE ELECTRONS) can wander about between the atoms. The more free electrons there are in a solid the better it will conduct electricity. The first diagram shows these free electrons moving randomly in a wire and the second how they move in one direction towards the positive when a battey is connected.

This drift of free electrons in a material is called an electric current.

Materials that will conduct electricity are called electrical CONDUCTORS (all metals (they contain a lot of free electrons) and carbon) those that wonít are called INSULATORS (dry wood rubber plastic polythene (they donít contain any, or many free electrons)).

© Keith Gibbs 2009