In 1911 Niels Bohr used quantum theory to explain how negatively charged electrons could remain in certain orbits without radiating energy. Patent 5695344 describes an educational demonstrator that simulates the theoretical orbital motion of electrons around the nucleaus of various elements.

The device works by magnetically deflecting a series of wires. Inside a container is an array of permanent magnets. On one side is an electric motor which is used to generate a rotating magnetic field. A series of thin wires are linked from a base unit to a series of coloured balls. These balls represent the electrons. Smaller permanent magnets are in turn repelled and attracted by the rotating field, causing the wires to perturbate freely. This in turn mimics the multiple orbital paths taken by each electron in its respective shell.