Repelling magnets


The game is composed of three flat magnets shaped like a disk with a hole at the center. These magnets are mounted on a ferromagnetic bar.
If we put the magnets on the bar so that their polarities repel reciprocally, they seem to float one over the other. The force with which two magnets repel increases when the reciprocal distance diminishes; it is possible to verify it by simply pushing down the upper magnet with your hand. In balance condition, the distance between magnets is that of the force of the magnetic repulsion (upward) when it has the same intensity as the force of gravity (downward).
This kind of interaction is a typical example of the force without any contact, the same as those ones acting between atoms and molecules at a microscopic level.