Video narration
If an electric field reaches a metal wire, does it simply pass straight through unchanged? Not quite. A metal wire contains free electrons, and an applied electric field pushes them. They begin to redistribute along the wire. That rearrangement is key: shifted electrons create their own electric field, opposing the applied field inside the wire. Motion continues until the two effects balance. In electrostatic equilibrium-the stable state of charges-the net electric field inside the conductor is zero. This zero-field result is for electrostatic equilibrium: electrons have not vanished; there is simply no net field driving further rearrangement. Any excess charge settles on the wire's surface, with the field perpendicular to it. So the wire itself doesn't let the field simply pass unchanged. It reshapes the electric field: its free electrons move until the field inside the conductor is zero.