Eli Whitney Museum

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.

The Vertical Needle

Stand a large nail up on a table and place your bar magnet above it. With
a little bit of patience you will be able to make the nail stand up vertically.

The Nail Train

Attach a nail to the end of a bar magnet. Attach another one to the end of that nail. See how many nails your engine will be able to pull.

The Repulsion

Straighten out a wire and put a round magnet down the wire. Then put another round magnet down the wire, making sure that two similar poles are facing each other. You will see that the lower magnet will repel the upper magnet, making it float.

The Spinning Compass

Hold your bar magnet close to your compass and watch what happens. Twirl the magnet in small circles around your compass. You will feel the magnetic pull of the compass on the bar magnet.

Magnetic Navy

Remove your sailboat from the plastic bag and twist the mast into the hole in the center of the boat. Fill a small plastic dish with water. Place your boat in the water and make sure that it is floating. Take out your bar magnet, move it around over the boat and watch the boat sail around the dish in a very lifelike way.

Remote Control

Place your bar magnet flat under a sheet of printer paper. Then place a few paper clips on top of the sheet and move the paper back and forth. You will see that the paper clips will perform in a intriguing way.

The Flying Trapeze

Suspend two nails from the poles of the bar magnet and let them swing. Attach a third nail across the two hanging ones and swing the nail back and forth. It will look like a flying trapeze.

Etch-a-Sketch

Place your bar magnet on top of your bag of filings and you will be able to see the magnetic field in the bag. See if you can draw your name in the filings.