How does an electroscope and electrometer work?

Question

Physics

Diagram of the operation of an electroscope and an electrometer.

Answer 1

An electroscope has a rod and petals attached to it. An electrometer has a rod and an arrow connected to it.
When electrified, the charge is distributed between all parts - the rod and what is attached to it. Because the charge is the same in sign - the petals (or arrow) begin to repel from the rod. More charge means more repulsion.

Answer 2

Google static electricity and positive and negative charges.