Check out ourMagnetism CD-ROMwhich includes similar activities.

Magnetic compasses work on the basic scientific principle known as the Law of Poles, which states that the north pole of one magnet will always be attracted to the south pole of another magnet. A magnetic compass works because its needle is actually a small bar magnet that aligns itself with the Earth's own magnetic field.

The Earth's magnetic field is generated deep within the planet by the motion of the liquid outer core, which contains highly conductive iron and nickel. When a bar magnet is free to swing, its south end will generally point to the Earth's magnetic north pole. In this activity, you'll create a simple compass and experiment with magnetism. (Remember: The Earth's magnetic north pole is not in the same place as it's geographic North Pole, or "true north.")

• Popsicle stick
• 3 small bar magnets with north and south ends marked
• cellophane tape
• thumbtack
• quarter
• steel bar
• piece of paper

1. Place the Popsicle stick on a flat surface, such as a table or your desk.
2. Take the first bar magnet and lay it on top of the Popsicle stick so that the magnet's north end is aligned with the top of the stick. Carefully tape the magnet in place.
3. Take the second bar magnet and lay it on top of the other end of the Popsicle stick, making sure that the south end of the magnet is aligned with the bottom of the stick. Carefully tape the magnet in place.
4. Place the thumbtack on the same flat surface so that the point is sticking straight up. Now, balance the Popsicle stick on the tack's point so that the stick is parallel to the flat surface. This will take some careful maneuvering.
5. Once you have perfectly balanced the Popsicle stick, carefully press down on it so that the point of the thumbtack sticks into the wood. Your compass should now be able to spin freely.
6. Answer the questions on the attached worksheet.