Don Durham, age 11, of Haynesville, Louisiana, for his question:

What makes a compass point to the north?

The compass you take on a camping trip is built around a magnet. That little needle which swings around to point out the north direction is a magnet. If you hang a small bar magnet on a string, it too will swing around until one end points north and other end points south.

There is magic in a magnet and you can learn a lot about it from a pair of toy bar magnets. Everybody knows that any magnet will pick up bits of iron or steel. To understand the compass needle we need to know a little more than this. We need to see how the magic in the solid magnet reaches out beyond it like an invisible halo.

Get some iron filings or flakes, and a sheet of paper. Scatter the filings higgledy piggledy on the paper and hold. the paper just above the magnet. The halo of invisible magnetic force around the magnet now goes to work. It pulls at the iron filings and arranges them in a telltale design.

If your flakes of iron are very fine, you will see them arrange themselves in lines. There will be clusters of flakes at the two ends of the bar magnet. The lines, which show the direction of the magnetic force, loop around from one end of the magnet to the other. This seems to indicate that the magic force runs in one direction down the magnet, swings outside, and loops back to the other end.

If this is so, then the two ends of the bar magnet are different. And so they are. The ends of a magnet are called poles. One is a north‑seeking pole, the other is a south‑seeking pole. Chances are, the manufacturer put an S on one and an N on the other end of your magnets to show you which is which.

Place your magnets end to end, almost touching. Two north‑seeking poles will spring apart, or repel each other, as will two south‑seeking poles. In magnets, poles which are alike repel each other place a north‑seeking and a south‑seeking pole together and they will draw together and cling.

In magnets, opposite poles attract each other.

All magnets in the world obey this rule. The biggest magnet of all is the earth itself. Yes, the solid globe on which we live is a giant magnet. It has two magnetic poles and a huge halo of invisible magnetic force. All other magnets feel the mighty power of earth's magnetism and obey it.

Remember, in magnets opposite poles attract each other. The pole of a small magnet which swings around to point to the earth's north magnetic pole must be a south pole. Actually, the point of a compass needle which points north is a south pole. People call it a north pole because it points north. If you wish to be in fashion. and also correct, you may call it a north­ seeking pole ‑‑ as Andy did in this article.