How does electricity actually flow through a wire?

Electricity flows through a wire via the movement of free electrons, which are loosely bound to metal atoms and can drift through the conductor. When you apply a voltage, it creates an electric field along the wire that pushes these electrons in a particular direction. However, individual electrons move surprisingly slowly, only about a millimeter per second on average, bouncing off metal atoms as they go. What travels fast, nearly at the speed of light, is the electric field itself. Think of it like a pipe full of water: when you push at one end, the pressure propagates almost instantly and water comes out the other end immediately, even though individual water molecules move slowly. The energy is carried by electromagnetic fields surrounding the wire, not by the electrons themselves racing through it.