The Speed of Light, Electricity, and the Electron

We often hear that light travels at (3 \times 10^8) meters per second—that’s about seven laps around Earth in one second, two seconds to reach the Moon, eight and a half minutes to hit the Sun, and just a few hours to reach Neptune. It’s mind-blowing speed, and nothing can outpace it in a vacuum.

But what about electricity? It’s fast, sure, but not quite that fast. Inside wires, electricity doesn't flow through a perfect vacuum—there’s resistance, collisions, and other factors. Consequently, the signal can move at anywhere from 50% to 90% the speed of light, depending on the medium and wire properties.

And then there’s the electron itself. The individual electrons that make up current don’t jet through the wire at light speed. Instead, they move with a drift velocity, shuffling along atom to atom as they pass the charge. Think of it like a line of ping-pong balls nudging the next one forward, rather than a single ball racing straight through empty space.

How fast is that?
Surprisingly slow—sometimes about the speed of a snail. The overall electrical signal moves quickly, but the individual electrons are just lumbering along in comparison. It’s another fascinating example of how the realities of physics often differ from our common assumptions.