#TruthBeTold
#electricity #wire #physics #science #telephone #SpeedOfLight #latency
The truth is...
The speed of electricity through a copper telephone wire is less than 5% of the speed of light.
#TruthBeTold = A statement that is logically or literally true (or partly true), but seems to imply something that isn’t true or is just plain weird. (for rhetoric, logic or propaganda studies… or just for fun)
(photo Attribution: Rembert Satow, wikimedia commons File:Birds_on_telephone_wires_at_Beeston,_Nottinghamshire.jpg)
Explanation (spoilers)
****** Spoiler *****
The rhetorical issue with this #TruthBeTold is that the words "speed" and "electricity" are are imprecise terms.
Usually the word "electricity" is referring to the electromagnetic signal or wave that flows through the wires, not the actual charge carriers -- especially in the context of telephone wires.
The word "speed" is not accurate because when we say "speed of electricity" we're usually referring to the *velocity* in a direction along the wire.
So, most people reading the statement would think that it's referring to the signal velocity (or wave velocity, or field velocity) which is typically on the order of about 50%-90% of c, depending on the type of wire.
However, the electrons in the wire actually move, on average, very slowly along the wire, about 1mm per second or slower. This is the drift velocity of the electrons.
(Also, each individual electron moves on it's own in mostly random directions within the wire, which is a much higher speed than the drift velocity.)
So "the speed of electricity" can be interpreted as the drift velocity, which is very slow.
Another rhetorical gimmick was that the statement said, "less than 5% of the speed of light" which seems to imply that the speed being referred to is very fast, which it is not. It's referring to the drift velocity.
So the statement in the #TruthBeTold toot is technically true, because 1mm/s is slower than 5% of c.
c = speed of light in vacuum
DC = direct current
AC = alternating current
