Making Magnets

Most recent answer: 10/22/2007

I would like to make a magnet. I read your answer to someone else asking that question, but I need much more specific information. I know you wrap insulated wire around the steel bar and run current through it. However,: 1) What gauge of wire, the heavier the better or the lighter gauge the better? 2) Does it matter how close together the coils are? Should I wrap more than 1 layer? 3) How much electricity should I run through the wire? Should it be DC only; not AC? 4) How long should I let it "cook"? How long should I let it stand with current, etc. running through it? Ten minutes? Over night? 5) If I am going to cut a 1"x1"x24" bar up into 1" squares, should I magetize it as a bar before cutting it up or will the cutting process destroy the magnetization? Where can I find this info (and perhaps more). I would like to REALLY know how to make a maget. I have been hunting all over, library, stores, internet, etc. If you find anything, or can tell me where, I would really appreciate the help.
- Kevin Humphries (age 15)
Lake Arrowhead, CA
Okay, first of all, always be careful when working with electric current. It's always good to have an adult help out with projects that involve electricity. Also, it would be a good idea to have an adult cut your metal for you since that’s a bit dangerous. A good alternative to cutting metal is to use a nail instead.

Now for the fun part. Once you have picked out your piece of steel to wrap your wire around, the strength of your electro-magnet depends on 2 things.
1) The magnitude of the current in the wire. You should use direct current (DC), which makes it easy since you can just use a battery.
2) The number of times you loop the wire around the nail.

As it turns out, the more loops of wire you have, the lower the current in the wire will be since its harder for the battery to push the electrons through a longer wire. Since more loops makes the magnet stronger, however, these two effects will tend to cancel, and you might think that it would not matter now many loops you had. Don’t forget, though, that a battery is not that good at producing a big current, so making lots of loops (resulting in a small current) is the way to go.

Be careful, you don’t want to leave the magnet on for a long time. The wires will get very hot. You don’t want to melt the insulation or start any fires. That’s why it’s a good idea to have an adult help you. I wouldn’t suggest leaving your magnet on for more than 30 seconds at a time. Give it plenty of time to cool down before trying again.

Have fun with your magnet, but be very safe too.


(published on 10/22/2007)

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