Question: Why do magnets repelle?

Susan Cartwright answered on 17 Jun 2015:

Magnets don’t always repel: like poles repel, and unlike poles attract. It’s basically the same physics as like charges repelling, and unlike charges attracting.

It’s hard to provide a decent explanation without going into complicated maths, which (a) wouldn’t be helpful and (b) I can’t format in this text editor! However, if you have a couple of small bar magnets, and a flat transparent box, you (or your class) can try the following experiment.

1. Get some iron filings (your school may have some, or you can buy them for £5.90 including postage from eBay) and pour a fairly small quantity into the box – not enough to fully cover the floor of the box.
2. Put one of the bar magnets underneath the box. You should see the iron filings form a pattern connecting the poles of the magnet. This shows you the magnetic field.
3. Bring the other magnet close to the first, and watch how the field distorts. This should give you a pictorial explanation of why like poles and unlike poles have different effects.