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You've seen the World's Simplest Motor ™...
But we have a classroom set so you can make one that's even simpler than that. Our classroom Homopolar Motor kit gives everything you need to make 10 complete motors. Watch the video to see how it works.
10 pieces of solid copper wire, 10 AA batteries, 30 washers and 10 small Neodymium magnets.
How it Works ...
This simple Homopolar Motor shows how moving charges (an electric current) experience a force when they move through a magnetic field. When the wire is in place, current flows from the battery's positive terminal, through the wire, radially through the magnet, and into the battery's negative terminal.
The direction of the force is perpendicular to both the direction of the current and the direction of the magnetic field, as demonstrated by the Left Hand Rule.
The magnetic field is vertical, relative to the table.
The current is radially inward at the lower point of contact, toward the center of the battery.
The resulting force on the current-carrying wire is tangential. The tangential force, or torque, causes the wire to rotate.
Note that only one connection to the magnet is necessary for the motion to occur. Creating two connections doubles the resulting force, creating a faster spin. Try bending the wire into different shapes, such as a spiral that rests one end on the positive terminal and curls around the battery.