Why Energy Doesn’t Flow Through Wires || Leonard Susskind

Описание: Most of us grow up believing that electricity travels inside wires, like water through a pipe. But that picture is deeply misleading. In reality, the copper is mainly a guide, not a highway. The wire’s job is to shape electric and magnetic fields in the space around it, creating the conditions that allow energy to move. The true action happens outside the metal, in the invisible fields that surround every powered circuit.

This idea comes straight from classical electromagnetism, first unified by James Clerk Maxwell. His equations revealed that changing electric and magnetic fields carry energy through space, even in everyday circuits. Later experiments by Heinrich Hertz confirmed that these fields can propagate as waves, proving that energy doesn’t need a physical substance to travel—it rides on fields. What we casually call “current” inside the wire is really just a supporting actor.

Inside the conductor, electrons drift only millimeters per second—far too slowly to explain how lamps light instantly or motors spin on command. Their slow motion merely sets up surface charges that organize the surrounding fields. Those fields then stream energy from the power source to the load through the space around the wire, guided by the conductor’s geometry. The wire is like a set of rails; the energy train runs in the air beside it.

So when you flip a switch, you’re not launching energy down a metal tunnel—you’re reshaping a field that already fills the room. Power flows through space, hugging the wire, slipping through insulation, and diving into components exactly where it’s needed. Once you see it this way, electricity stops being something trapped in copper and becomes something far more elegant: energy moving freely through the fabric of space itself.