Intro: So I know what your thinking, what on earth is a homopolar motor! Before I can show you how to make one of these simple and fun to watch motors' you might want to know what it is and how it works first, right?
How it works: The homopolar motor is driven by the Lorentz force: as it moves through a magnetic field, the conductor is pushed through a magnetic field by opposing forces. This force induces a torque around the axis of rotation. Because the axis of rotation is parallel to the magnetic field, and the opposing magnetic fields do not change polarity, no commutation is required for the conductor to keep turning.
Brief History:In 1821, soon after the Danish physicist and chemist Hans Christian Ørsted discovered the phenomenon of electromagnetism, Davy and British scientist William Hyde Wollaston tried, but failed, to design an electric motor. Faraday, having discussed the problem with the two men, went on to build two devices to produce what he called "electromagnetic rotation". One of these, now known as the homopolar motor, caused a continuous circular motion that was engendered by the circular magnetic force around a wire that extended into a pool of mercury wherein was placed a magnet; the wire would then rotate around the magnet if supplied with current from a chemical battery. These experiments and inventions formed the foundation of modern electromagnetic technology.
Materials needed: Copper wire, Double A battery, 1 half inch diameter cylindrical neodymium magnet, Needle nosed pliers, and a wire cutter.
Step 1: Get the Materials
Before you can start making a homopolar motor you need a double A battery, Copper wire (The thicker the wire, the slower the motor will go), Neodymium magnet (also known as "rare earth magnets"), Needle nose pliers, and a Wire cutter.