Charged objects push or pull on each other even when they are not touching. This is a non-contact force. Its direction depends on the type of charge on each object.
Like charges repel. Two positive objects push apart, and so do two negative objects. Unlike charges attract. A positive object and a negative object pull towards each other. The force gets stronger as the charges are brought closer together.
You can test this with rods. A polythene rod rubbed with a cloth gains electrons and is negative, while an acetate rod rubbed with a cloth loses electrons and is positive. Hang one rod from a thread and bring a second rod near. Two polythene rods swing apart, but a polythene rod and an acetate rod swing together.
