Magnets are able to push and pull on each other without touching because of magnetic force between them. Magnets are materials that emit a magnetic field, which attracts certain metals. Magnets have many uses in the modern world, from industry to stereo systems. Teaching about magnetism often involves demonstrations of the more interesting effects of magnetism. One of the most popular demonstrations of magnetism is magnetic levitation.
With a very simple set-up one magnet can be made to cause another magnet to levitate—float in midair. It can even be made to carry a load. This is because every magnet has two poles and like poles repel each other. Magnetic levitation is an excellent demonstration of the relative strengths of two fundamental forces, magnetism and gravity. Though the entire earth is pulling on the floating magnet and its load gravitationally, just one tiny magnet can overcome that downward pull with magnetism and cause it to rise into the air.
Hold one magnet in each hand. Bring them close to each other. If they try to pull each other closer then turn one of them around. If they try to push each other apart then mark the sides that faced each other with the marker. You know that these marked sides are the same magnetic pole, because like poles repel.
Set up the clamp stand. Extend the clamp arm out as far as possible to give yourself room to work. Adjust the clamp to the width of the tube. Set the tube in the clamp. Set the tube so that its bottom is a little higher than the width of your finger plus the width of one of the magnets.
Place the load on top of one of the magnets, on the unmarked side. Put the magnet and load into the bottom of the tube with the marked side down and hold it with one finger so that it does not fall out.
Place the other magnet directly underneath the bottom of the tube, with the marked side up. Remove your finger. The magnet on the tabletop will repel the magnet in the tube and make it levitate along with its load, as long as it is not too heavy.
If the magnet will not levitate with the load on it, the load may be too heavy. If the magnet will not levitate without the load then the magnets are too weak for this demonstration. Refrigerator magnets will not work. The tube is needed to keep the levitating magnet from “falling off” the magnetic field that holds it up. If you cannot find a clamp stand, a substitute can be easily made. Cut a hole in a piece of cardboard, making the hole the same diameter as that of the tube. Suspend the tube above the table on two piles of books. You may need to tape the tube to the cardboard.