>In metals, electric current is a flow of electrons. Many books claim that these electrons flow at the speed of light. This is incorrect. Electrons in an electric current actually flow quite slowly; at speeds on the order of centimeters per minute. And in AC circuits the electrons don't really "flow" much at all, instead they sit in place and vibrate. It's the energy in the circuit which flows fast, not the electrons.
> Metals are always full of movable electrons. In a simple circuit, all of the wires are totally packed full of electrons all the time. And when a battery or generator pumps the electrons at one point in the circuit, electrons in the entire loop of the circuit are forced to flow, and energy spreads almost instantly throughout the entire circuit. This happens even though the electrons move very slowly.