One AA battery, two circular magnets and a conductive surface is all you need to make a self-propelled motor.
Called homopolar motors, they are the simplest motors around and use direct current and two magnetic poles to move. While many variations of homopolar motors exist, the YouTube channel Magnetic Games seem to be the first to use two magnetic discs to make them move like little vehicles.
Homopolar motors were first demonstrated by Michael Faraday in 1821. Faraday is best-known for discovering diamagnetism, electrolysis and electromagnetic induction.
Watch the video above to see the batteries in action.
Source: Popular Mechanics USA
Video credit: Magnetic Games