MadSci Network: Physics |
Which is faster -- electricity or light? Light wins! (sort of...) This is because the speed of light is the ultimate limit. According to Einstein's special theory of relativity nothing can go faster than light. And nothing that has mass (weight) can ever quite get to the speed of light, because it simply takes too much energy to accelerate it that far. The electrical current carried by a typical copper wire is actually carried by many millions of electrons which are constantly bumping into one another and into other atoms in the wire. This tends to slow them down so that they never get anywhere near the speed of light. However, when you start studying physics in school -- one of my favorite subjects -- you'll discover something neat. It turns out that changing electric fields generate magnetic fields, and changing magnetic fields will generate an electric field. And light itself is just an electro-magnetic field that oscillates at a frequency that our eyes are sensitive to, so we can see it. It was quite a surprise to most physicists in the last century when it was demonstrated that the speed of light was exactly the same as the speed of the electric or magnetic field. They were all really the same thing! So as it turns out, the electrical SIGNAL that is being transmitted through a wire is actually moving at the speed of light, even though the individual electrons which carry the current aren't traveling anywhere nearly that fast. Cool, huh? Well, I suppose that's probably more than you wanted to know. I hope it didn't confuse you. Thanks for asking! --Bill Reisdorf--
Try the links in the MadSci Library for more information on Physics.