You will need:

• bar magnets (several different sizes)
• horseshoe magnets (several different sizes)
• 20 metal paper clips

Introduction:

Some magnets are stronger than others. The force of magnetism is always strongest at the pole of a magnet.

Procedures:

1. Pick up one paper clip with a horseshoe magnet. Now put a second paper clip near the first one. It will cling on, because magnetism travels through the first paper clip and attracts the second one.

2. Add more paper clips one at a time to make a chain. Record the number of paper clips that the magnet can hold.

3. Next, use the other side of the horseshoe magnet to make a chain of paper clips from one pole of a magnet to the other pole. Can you use more paper clips if you use both poles?

4. Repeat the steps above with each magnet.

5. Now find out where the magnetism is strongest on one magnet. Start the chain of paper clips from three different parts of the same bar magnet. Start once with the north pole, once with the south pole, and once in the middle of the magnet. Where is the magnetism strongest?

Discussion:

1. Which is the strongest magnet?

2. Are the biggest magnets also the strongest ones?