Pick up the needle and magnet. Take the needle and run it down the magnet a few times. Make sure to only stroke in one direction, not back and forth. The motion should be similar to striking a match.
Cut a round piece of cork about 1 inch in diameter and one-quarter inch thick using the knife.
Insert the needle through the side of the cork as close to the middle as possible. Do not push the needle through the middle of the cork. The needle should be horizontal through the cork, not up and down through the center.
Place the cup of water on a flat surface.
Put the cork carefully in the cup of water. Watch as the cork floats parallel to the water and spins until one end of the needle is pointing north.
