What's the difference between electron movement and charge movement in electricity?

Question

Possible Duplicate:
how does electricity propagate in a conductor?

I have read that in an electrical wire electrons movement is very slow while the energy or charge is very fast. What's the difference anyway?

Answer 1

I'm sure this is a duplicate question, but I've searched and haven't found an exact duplicate.

Anyhow, an analogy commonly used is to imagine the electricity flowing in a circuit as water flowing in a water pipe. In this analogy the electrons are the water and the voltage is the water pressure. The battery in the circuit would be represented as a pump.

If you suddenly increase the pressure of the water e.g. by turning the pump on (equivalent to connecting the battery) then the pressure change will flow round the circuit fast. In fact it would move at the speed of sound in water, which is about 1.5 km/sec, even though the water would be moving much more slowly than this.

Going back to the electric circuit, the signals travelling round the circuit are changes in voltage and move at around the speed of light, just as the pressure change moves at the speed of sound in a water circuit. However the electrons would be moving far slower than this.