Electricity
 

Static electricity

Static electricity occurs when an electric charge builds up on an object. This build-up can happen by rubbing one material against another. Electrons are rubbed off one of the materials, which then becomes positively charged, while the other material which gains the electrons becomes negatively charged. The two materials then attract each other, for example rubbing a balloon against a woollen jumper.

When a charged object is connected to another object or to the Earth, electrons flow between the objects. This can be experienced as a slight shock by a person when a car door is touched after moving against upholstered seats or as the crackling sound of hair when it is combed after being washed and dried.