Dear Dr. Staff: How come we can plug something into the wall and turn it on? I mean, what is inside the little slits in the electric outlets that makes it so that we can operate neat things like television sets and Nintendo games? I went and asked my Pappy what it was, and he said that Nuclear Power Plants pump radioactive chemicals into these tiny pipes that go through the wall, and that when you plug something into the wall, it fills up with radioactive stuff and starts to work. I didn't believe him, though, because he's usually wrong, so I went and asked my Uncle Smiley. Smiley said that there's these little things called eclectrons or something like that that the power plants stuff into wires, and that these things power stuff by running in circles. But that doesn't make much sense to me, since I never got anywhere by running in circles. And how do these eclectron-things work, anyway?
Dear Hungry Sense: Well, they're both wrong, in different ways. What a nuclear power plant does is generate heat. This heat is used to heat up one end of a long metal wire. As you've seen when you pick up a cast iron skillet that's been sitting on the stove (and then dropped it on your foot), heat travels through metal. So the heat travels along the wire, to the other end, which is in the wall outlets in your house. When you plug your television set into the wall, the heat travels along the wire into the TV, and heats up the back of the television tube. This is where those electrons come in. There are some electrons at the back of the tube that get heated to different temperatures based on the television signal coming in. When they elect to, they jump off the back of the TV and onto the front of the TV screen, lighting it up and forming a picture of the Ed Sullivan show. (That's why they're called electrons, because when they elect to jump it forms the picture.) But, some of the heat is wasted in the system, which is why the back of your TV set warms up as it operates. Other electrIcal devices work in the same manner, powered by heat. This is why all the ways you've heard of that generate "electricity" do so by making heat.
