Have you ever been lost at sea on a foggy night? Before approximately 1100 A.D., you would have been claimed by the open ocean. If you were born shortly thereafter, you might have brought along your trusty lodestone.
The lodestone was the earliest form of a compass. It was first found in a town called Magnesia, in Asia Minor. The inhabitants of the town discovered that if you put the stone in water it would point almost directly north and south. This is because the earth is a giant magnet with north and south poles. The magnetic north and south poles are actually quite far away from their geographical namesakes. About every 400,000 years, the earth’s magnetic poles switch. No one can really explain how or why this happens. Over the course of 900 years that have passed since the Magnesians discovered the compass, its technology hasn’t changed much.
Magnetism is one of the fundamental elements of our society today. Magnets can be found in any electric motor, refrigerators, tools and utensils, and even some games. Magnets have two poles, the north and south poles. When two like poles are put together, they repel, but when unlike poles are put together, they attract each other. In the atoms (the smallest particles of matter) of all materials, there are electrons revolving around the nucleus of the atom. Each electron is a small magnet. However, in unmagnetized materials, the electrons are all jumbled up. In a magnet, the electrons are all lined up, creating a magnetic force. In magnetic materials, like iron, the electrons can be lined up when in the presence of a magnet.
The best way to understand magnets is to use them -- so let’s see what you can discover.
