Here is a simple experiment that will teach you an important electrical
lesson: On a cool, dry day, scuff your feet along a carpet, then reach
your hand into a friend's mouth and touch one of his dental fillings.
Did you notice how your friend twitched violently and cried out in
pain? This teaches us that electricity can be a very powerful force,
but we must never use it to hurt others unless we need to learn an
important electrical lesson.
It also teaches us how an electrical circuit works. When you scuffed
your feet, you picked up batches of "electrons", which are very small
objects that carpet manufacturers weave into carpets so they will
attract dirt. The electrons travel through your bloodstream and
collect in your finger, where they form a spark that leaps to your
friend's filling, then travels down to his feet and back into the
carpet, thus completing the circuit.
Amazing Electronic Fact: If you scuffed your feet long enough without
touching anything, you would build up so many electrons that your
finger would explode! But this is nothing to worry about unless you
-- Dave Barry, "What is Electricity?"