How to Make a Magnet Levitate

Video Transcript

"Hi, I'm Steve Jones, and I'm going to explain how to make a magnet levitate. Why does a magnet levitate in the first place? Usually we use this idea that two identical poles will repel, so these two repel, that is they push each other apart. Now normally what would happen of course if you place them side by side, they will push each other apart and stop. Obviously it can't levitate in that sense because there's nothing guiding it, there's nothing to stop it just falling over, so that's not really going to help us very much. But that is the principle, that we have to create some how poles on a magnet, two, similar poles which will create repulsion. The easiest way to do that is not to use permanent magnets, but to use electro magnets. And here we have an electro magnet, it's a cardboard coil with a wire wrapped around it, but through the center we've put a bar of iron. Now what that means is the iron makes the magnetism much stronger, while I switch on the electric current here, it makes the bar magnetic. The magnetism is concentrated in the iron bar. Now if I, say, take an aluminum ring, something like this, or a copper ring, but aluminum is very good because it's light, but if I make that, and I make it and put it over the iron core, what actually happens is this: This coil creates a magnet in here, but this magnet here in a reverse way generates a current in here, and turns this ring into a little magnet. And the thing is, if it's a north pole here, it will be a north pole at the bottom there. So that's north and that's south, but this will be north at the bottom and south at the top. What that means is, that this coil will repel this coil. That means that when I switch this on, this will move up here, and it'll move up only as far, lets say there, because if it went further the force gets smaller, if it gets closer the force gets bigger, so it finds a balancing point, and at that point it will stay. And that is our levitation. So what we do to make a magnet levitate is to create an electro magnet, strike the edge with an iron bar and put a little coil on the top, and we should see that coil levitate above the other magnet."