This message was inspired by the text that currently appears at the bottom of the messages written by James Edgar (UT member #015866): "No trees were destroyed in sending this message. However, a large number of electrons were diverted from their ordinary activities and terribly inconvenienced."

My comment is that it is interesting to note that there are actually three different speeds when you talk about electric current. I got the following information from one of my courses in electricity.

First, the speed of the electrical current "itself": I mean the propagation speed of the signal, is equal to the speed of light in the cable (which is slightly less than the speed of light in a vacuum). Around 200,000 km/sec.

The speed of the individual electrons (random movements) is the same whether there is a current or not. It is very high - on the average, something around 50,000 km/sec, if I remember correctly; the exact (average) speed depends mainly on the temperature.

And finally, there is the drift speed (?) - the average speed at which the electrons move, say, from left to right. When there is no current, this speed is zero. When there is, surprisingly, this speed is extremely slow - a typical speed might be 1/20 mm/sec. The exact value depends on the number of free electrons (this, again, depends on the material), the cross-section of the cable, and the current (in Ampère).

(Some people think electrical current is identical to "movement of charge". Textbooks for beginners might actually define it this way, and an electrical current usually involves movement of charge, but the definition is far from complete.)

(For those who live in the US: one mm. is approximately 1/25"; one km. is approximately 2/3 mile.)

I thought you might find this interesting (for those who didn't know it already).

Regards, Hilmar.