Animation showing the behaviour of individual dipoles within a magnetic material. The dipoles are individual atoms with unpaired electrons, whose angular momentum and spins can align to produce the visible effects of magnetism. In some materials, the dipoles interact and spontaneously align with each other, forming regions called domains, where all the dipoles are aligned. This is the case in ferromagnetic materials, which can form permanent magnets. In these materials, large regions of the material have their dipoles aligned. Most materials exhibit paramagnetism, where the dipoles only align in the presence of an external magnetic field. Any magnetic material can have its magnetism destroyed by heating above its critical Curie temperature. At this point (such as in the middle of the clip), the thermal energy of the atoms overcomes the magnetic effects, and the dipoles' directions are randomised. As the material slowly cools below this point again, the dipoles once again align.