Robert McGowan, age 9, of Cape Elizabeth, Maine, for his question:
How can a magnet run a compass?
If you have two small bar shaped magnets to help you, you can figure out part of this puzzle for yourself. But the part you figure out leads you to an even bigger puzzle. This second puzzle goes back to the people who invented the compass many ages ago. They made a slight mistake.
An experiment is a sort of test. It can prove whether an did idea is true or not. It can prove a brand new idea to be true or false. And an experiment often can help you to solve a tricky problem for youself. No young science student is too young to do experiments to help him brighten up his brain power. You need to try one of these test games to understand the tricks of the magnet in a compass. Find two small bar shaped magnets.and a quiet table where you can use them to do some thinking. Chances are, each magnet has a letter N on one end and a letter S on the opposite end. The letters stand for North and South.
Place your magnets on the table top and slither them around a bit. You may notice that they push and pull each other, almost as if they are alive. If you place them in a line end to end, they may cling together. Or they may pull apart. If they cling, you can bet your boots that the S end.of one magnet is touching the N end of the other magnet. Attraction is the right word for this kind of clinging. In magnets, opposite ends attract each other.
Now notice what happens when you touch together the two N ends of the magnets. They pull apart frcm each other with a little jerk. They repel each other. The two S ends also repel each other and spring apart. The N .and S ends are poles and every magnet has a north and south pole. Its north pole is attracted by the south pole of every other magnet. Bigger and stronger magnets have more power to attract and repel. And the biggest magnet in our world happens to be the planet earth itself.
The earth also has a North and a South Magnetic Pole. If you hang a little magnet on a string, the earth pulls it. around so that one of its poles points toward its strong North .
Magnetic Pole in the Arctic. This end of your magnet acts like a compass and points to the north direction of the earth. The other end, naturally, points to the earth's South Magnetic magnet
People discovered this trick and made compasses ages ago. Some hung a thin sliver of magnet on a string. Some floated a small magnet on a cork raft in a dish of water. The magnet must be fixed so that it can swing around freely. Nowadays, we fix a magnet needle to swivel around on an upright pin.
We know that the early compass makers made a mistake. Remember, the opposite poles of magnets attract each other. Ages ago, people thought that the earth's North Pole pulled the north pole of a magnet. They called this point of the needle the north pole of the compass magnet. And we still do. But people in the know remember that the earth's North Magnetic Pole really makes the south pole of the compass point north. These people also know that the big earth makes the little compass needle work, whether our name for the end of its magnet is right or wrong.
Some people, however, are very fussy about sticking to the scientific facts. They cannot abide calling the poles of our magnets by their wrong names. So they invented a sneaky way to get around it. They call the point of the compass needle the north seeking pole of the magnet. This is true, because it does move around to seek out the north direction. The opposite end of a compass needle is the south seeking pole of the magnet, which is also true. In any case, everyone knows that the compass needle points to the earth's North Pole, which is in the Arctic.