Electrons are tiny particles that orbit the nucleus of an atom. Here is a
drawing of atoms inside a piece of metal wire.
When enough electrical energy is added to the electrons-after flipping on a
switch, or plugging in a cord, or adding a battery-they can escape from
their normal orbit and flow along a path.
That's mostly how people use electricity . . . we make it flow along a path
into things like light bulbs, refrigerators and CD players. The path
electrons follow is called a circuit.