I have made a new version of Faraday's homopolar motor. This was the first device to demonstrate the connection between electricity, magnetism and motion. Faraday's motor included a beaker of mercury as the outer conductor. This has been demonstrated in classes. My motor comprises gold-plated copper conductors and strong ceramic ring magnet. Below is a link to a video of this movie in youtube. There are lots of other homopolar motor videos on youtube but most use a small neodymium magnetic and you cant easily see why how works.
In the motor I made, there is a fixed, gold-plated post at the center and a fixed gold plated copper ring concentric with the post. A ring magnetic inside the copper ring has a field which is mostly vertical at the height of the top of the copper ring. A gold-plated wire rests on the inner post and the outer ring, which are connected to 6 volt battery terminals. A current flows through the wire. Since there is a vertical magnetic field, there is a Lorenz force in the azimuthal direction, which moves the wire in a circle.
It shows that if there is a current carrying conductor perpendicular to a magnetic field, there will be force on the conductor that is perpendicular to both the current and the field.
http://www.youtube.com/watch?v=bjSZAFD5Txw
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