| When the surface
of the plastic is rubbed, negative electric charges are transferred
from the users hand to the plastic. These negative charges
attract the positive charges in the black bits of Formica below.
In places where the attraction is strong enough, the bits jump up
to the plastic. When one of the bits jumps up and touches the plastic,
negative charges from the plastic flow into the bit, until both
the plastic and the bit have the same charge. With the charge difference
neutralized, the bit and the plastic no longer attract one another,
so the bit falls back down.