How to Make an Electromagnet

Video Transcript

"Hi, I'm Steve Jones, and I'm going to explain how to make an electromagnet. Well, first of all, why would we want to make one? Well, an electromagnet has advantages. It can be switched on and off, and that is why we would use an electromagnet, rather than a permanent magnet. In addition, we can make it much stronger, probably, than a normal permanent magnet, and we can change the strength of the magnet also. The basis of an electromagnet, is a coil of wire. The wire has to be insulated of course, and it has to be wrapped in a circle, around some kind of former. Some magnets are this shape, and the wrapping of the wire around this, is exactly the same. You start here, and you wrap it, and it keeps wrapping all the way around. I'm just doing a few of these turns, but it doesn't make any difference. It is simply of that kind of shape, and if you pass a current through that one, one end will be a north pole, the other will be a south pole. This is very useful for making very, very strong magnets, but if we don't need it to be that strong, we can use a straight piece of cardboard, or something else like that. Wrap around your coil, a couple of meters of single coil wire, and then pass the current through. It will be magnetic. What is always important, is that normally we put in a core, and the core is made of soft iron, that is, iron which is easily magnetized, and de-magnetized. You don't want a steel core, because that will become magnetic, and stay magnetic. You want a soft iron core. It will magnetize and de-magnetize, and that will enable you to switch your magnet on and off, which is what you want to do. If you want to make it stronger, you can increase the voltage, and hence, the current. This will make it stronger, or you can of course, increase the number of turns of wire, so both of these things will make your magnet stronger, and that's the only thing that makes an electromagnet of advantage, that it can be stronger, and it switches on and off, so that is basically, how to make an electromagnet."