These round, flat, disc magnets have very defined poles at opposite ends of their diameters. They will raise many interesting questions for students during their studies of magnetism. Is there a top and bottom to the magnets? Why can they be stacked? How do you get them to repel? Try some collision in 2-D experiments with these disc magnets. You'll like the outcomes. Six ceramic disc magnets per set. Each magnet is 25 mm in diameter and 5 mm thick.