Magnetic Toys
Firstly, we have an example of diamagnetic levitation. Diamagnetic materials are repelled by both the north and the south pole of a regular magnet. However the effect is a very weak one. Water is diamagnetic, and also a substance called pyrolytic graphite, which we show here.With a small2 x 2 array of powerful neodymium magnets, it is possible to levitate a small piece of pyrolytic graphite. The second toy involved correlated magnets. This type of magnetism was only invented in 2008. Basically correlated magnets normally work in pairs, and have a complex arrangement of magnetic elements (maxels) on their surface; these can vary in size, orientation and location. In combination, the two magnets can be made to attract at a distance, but repel if they get too close (a combination of longer range and shorter range magnetic forces). In this example, the magnets are extremely hard to separate when they are in one orientation, but if you rotate them 180 degrees, they can be separated more easily.
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