We have been investigating magnets in our school lately. The children were introduced to a large horseshoe magnet and various objects to pick up.
After this, we put out a small magnetic car with a smaller magnet. They really enjoyed making the car "go" with the force of the magnet.
After a few days of playing with the magnet and the car, we then put out Magnetic Match Rings. Here the children can just explore with the magnets or follow a card and match the magnets. Using the rules of magnetism, to make the rings float, you must use like or the same poles. Opposite poles attract. Each ring has a positive and negative pole, it was really fun experimenting with these magnets.