Introduction to Magnetism

Introduction to Magnetism

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The first magnets were discovered in ancient Greece. These were naturally occurring magnets, called lodestones. Lodestone is considered a hard, or permanent magnet. It does not require any outside force to be a magnet, and holds its magnetic force independently.

Any minerals that are attracted to a magnet are considered a soft or temporary magnets. Iron can be a soft magnet, but it can be a permanent magnet too. Have you ever rubbed a paper clip with a magnet? After a good many rubs, the paper clip it self became a magnet. Iron is a metal that can be made into a magnet.

Iron can be made into a magnet by several means. One way is to hammer a piece of iron into a cylinder shape, and allow it to cool near a hard or permanent magnet. Now, most of us do not have the blacksmith tools to hammer iron into this shape, so we can make iron magnetic simply by rubbing a magnet onto the surface of the iron. It has also been said that iron could be made into a magnet if it were hammered hard enough. The magnetic poles of the earth would turn the iron into a magnet by pulling the electrons into place. I do not believe this has every been done, but it's a heck of a theory.

Just about everything has some sort of magnetic force. Our entire nervous system works via electrical means and as we discovered last week, our bodies do contain iron.

As William Gilbert, an English scientist, discovered in 1600's, the earth is one very large, but very weak magnet. The earth, as with all magnets contains both a north and south pole.

In theory, if there were no friction on earth, in the shape of trees, hills, mountains and the like, everything magnetic would travel to one of the earth’s poles. The magnetic poles of the earth are actually over 1,000 miles away from the geographic poles. When a compass points north, there is a slight difference between the geographical north and the magnetic north. A correction of 0-25 degrees is required, depending on where you live to enable you to find geographical north, when using a compass. Folks living on the agonic line do not need to make any corrections, since thier compasses will point to the true north.

Magnetism and Electricity are very closely linked. In 1820 a Danish scientist , Hans Oersted noticed that an electrical wire which was part of a closed circuit acted as a magnet. As long as current flowed through the wire, that wire would contain a certain degree of magnetic

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