There have been many attempts to use magnets to make perpetual motions devices, relying on the attractive and repulsive qualities of magnets to make a wheelspin endlessly. Anyone who's seen a video clip online or read about magnetic propulsion may naturally wonder how exactly magnets can turn a wheel. The numerous techniques used to attempt to create efficient perpetual motion devices require a great deal of further reading to understand and replicate, but the process of actually getting a wheel to move using magnets can be replicated easily at home.
Identify the north end of your bar magnets. You can do this many ways, but they generally revolve around the fact that the earth is magnetised. If you tie some string around one of your bar magnets and let it dangle free, eventually, it will settle in alignment with the earth's poles. The side pointing north is referred to as the north side of the magnet. You can also hold a compass pointer to a bar magnet to determine its polarity. The compass will point to the south end of the magnet, because the pointer is also a north magnet, and opposites attract.
Use the magnet you know the polarity of to determine the alignment of the others. Hold out the north end, and it will attract all the south ends of the other magnets. This is the basis for making a wheel move with magnets. Wheels are already designed to turn efficiently, so all you need is force, like that caused by magnets being in close proximity to one another.
Attach magnets to the outer edge of half of your wheel. Any strong glue will be sufficient to affix the magnets. Arrange the magnets so that all of the north ends are on the outside of the wheel, and lay them at around a 45 degree angle, all pointing in the same direction. Lay them out without gluing as a test, to see how many magnets you need to cover half of your wheel. Put all of the magnets that are going to be affixed to the wheel together and weigh them. You will need an equal amount of non-magnetic weights for the other half of the wheel.
Attach the weights to the other half of the wheel. The idea is to get a balanced wheel, so it still turns well. Arrange the weights in a semi circle, following the wheels curve and trying to keep the weight as balanced as possible.
Hold or set the wheel down either vertically or horizontally. Try to keep the wheel as level as possible, but still free to turn.
Move the north end of your strong magnet close to the wheel. In theory, the closer it is, the faster the wheel will turn once it is started. Leave around 6 inches of space between your wheel and magnet and spin the wheel in the direction the bar magnets are facing. The north ends of the magnets should be repelled around in the direction they are pointing, and the more inner wheel south ends.
Things you need
- North/south aligned bar magnets
- Non-magnetic weights
- Small, working wheel
- Strong adhesive
- Large, powerful magnet