There are two kinds of electricity – the kind that moves briskly along in what we call an electric current, and the kind that sits around, piling up, on a surface of an object. The word static means “unmoving” or “unchanging,” so you can see that static electricity is the latter kind.
Things are made of stuff, what we call matter, and matter is made up of atoms that are usually electrically neutral. That is, atoms generally have no positive or negative charge. The reason that atoms are electrically neutral is that they have the same number of positive particles (protons, found in the central nucleus) and negative particles (electrons, found in the outer cloud surrounding the nucleus).
The thing is, electrons can get bumped off when two surfaces come into contact and then separate again. When it loses an electron, an atom has more protons than electrons, and so it has a positive charge.
Also, an atom can collect the bumped-off electron from another atom; when that happens, it has more electrons than protons, and so it has a negative charge.
Static electricity can build up and build up, with more and more atoms getting brushed together and losing or gaining electrons, until finally it is discharged by flowing to the surroundings. People can feel, hear, and often see a spark as static electricity is discharged.
Examples of static electricity vary from socks rubbing together in the drier to lightning, which is probably caused by ice particles bumping together in a cloud. Static charge can be very dangerous – we are warned, for example, not to repeatedly get in and out of our seats at a gas station, as the rubbing of car seats and clothing could cause a build-up of static electricity, any discharge could cause a spark, and sparks are dangerous at a gas pump! But static electricity can also be harmless fun – such as the crazy hair-dos created by rubbing a rubber balloon on our hair!
Find out more...
Science Made Simple has an article about static electricity and four activity suggestions. Science Kids has a much shorter, simpler article on static electricity.
I like this simple, clear demo of water and static electricity—this is one experiment that would be easy to do at home!
People at science fairs use Van de Graaff generators to demonstrate static electricity. Here is a vivid demo of hair “standing on end” because of static electricity. And here is Steve Spangler demonstrating the generator.
Also on this date: