| Magnets are usually made of iron or steel. |  |
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Powerful magnets can be made of special alloys of aluminium, cobalt, copper, nickel and iron. |
| Materials can be permanent magnets. |  |
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Materials can be induced magnets. |
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| Magnets are usually made of iron or steel. | |
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Powerful magnets can be made of special alloys of aluminium, cobalt, copper, nickel and iron. |
| Materials can be permanent magnets. | |
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Materials can be induced magnets. |
| All materials are made of very small particles called molecules. The molecules of iron and steel are magnetic. The Molecular Theory of Magnetism suggests that in a magnet all the molecules are lined up with their own North-seeking and South-seeking poles as in the diagram. This means all the souths are pointing one way and all the norths pointing in the other direction. |  |
| In an unmagnetised piece of iron or steel the molecules are arranged at random with the poles pointing in lots of different directions. |  |
| You can show this with a large test tube of iron filings. The tube must be almost full and corked securely. the iron filings can be seen to lie in almost every direction. If you bring this tube towards a compass needle, it has almost no effect on the needle. Stroking the test tube, in a horizontal position with the North-seeking pole of a magnet causes the iron filings to line up as in the diagram. |
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