Cool car built from a battery and two magnets How to make the simplest electric car toy from 1 battery and 2 magnets:
Put round magnets on either end of a AA battery and set it down on a sheet of tinfoil and watch it spin! It’s a homopolar motor, a simple electric motor that relies on the Lorentz effect to set it in motion.
If you take two circular magnets and slap them on the ends of a AA battery, the resulting axel will drive on a road of aluminum foil. This is called a homopolar motor and it’s one of the simplest machines you can build.
…the homopolar motor works because the combination of the flow of the electric current (from the battery) and the flow of the magnetic current produces a torque via the Lorenz force.
This short video explanation should give you a good idea of the principles involved.