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.
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