Materials conduct because they contain that can move around them.
In solids these charged particles are called .
Electrons are tiny charged particles.
In some materials the electrons can wander about between the , these electrons are called
. The more free electrons there are in a solid the it will conduct electricity.
If we now think of the as a as shown in the diagram then the show no particular direction of (Figure 1(a)).
But if we now to the two ends of the wire the electrons the wire in direction (Figure 1(b)).
The drift free electrons material is called an .