DISCOVER
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Video transcription

Hi I'm Steve Jones and I'm going to explain how electromagnets work. First of all we know what a magnet is. A magnet is a piece of metal and it has one end as we know that is North and the other is South. This bar, it is called a bar magnet, this bar of course is a permanent magnet so we call this a permanent magnet. Now it has disadvantages so the electromagnet is in a sense exactly the same as a permanent magnet. It has a North and a South but the way we get that North and South is by passing the electric current around a wire wrapped around some coil of some kind. This could be a cardboard tube for example. If I wrap it around I will get a North at one end and a South at the other as the current travels through it. When I switch it off I get no magnet so this is why we call it an electromagnet because the electricity creates the magnetism. Now obviously this magnet is different from this one. First of all there is no metal in it except the metal in the wire carrying the current but if I put in the center some iron then it will make it very much stronger, maybe 10 to 20 times stronger so that is a proper electromagnet so down the center of the coil I put a soft iron core, soft doesn't actually means it is soft it means it is easy to magnetize. So this coil will magnetize easily and equally easily demagnetize. Why an electromagnet? Why should we use one? Well the answer is it is because we can switch it on and off that it has an advantage. If I want to piece up a piece of metal and then drop it, if I can switch this on and off it is easy but if I try and do it with a permanent magnet of course I won't succeed because I can't switch this magnetism so that is basically how an electromagnet works.