P4 - Static Electricity

When 2 insulating materials are rubbed together (using friction), electrons pass from one to the other. This leaves a positive charge on the other one, because losing electrons adds charge. It also leaves a negative charge on the other object because it has now gained electrons.

Only the electrons can move - the positive charge CANNOT move.

This is because the positive charge is only created by the movement of electrons.

When a charge builds up, it can suddenly move, causing sparks or a shock.

This can be dangerous, or it can be harmless, like when you touch someone and you get a small shock.

Opposite charges ATTRACT.

Identical charges REPEL.

So;

+ and + = repel

- and - = repel

+ and - = attract

- and + = attract