Magnetism & Engineering

VansenS

Can someone explain this video:
http://www.youtube.com/watch?v=BRQ66GtA0wg


If I put this together myself should I expect it work or is that some hoax? If that's just a normal use of magnetism, then where can I read more about the principles behind it? Do these magnets get weaker over time?

Redbelly98

From a recent comment on the video:
In other words, by moving the hand-held magnet he does work (i.e. supplies energy) on the system.

If you do build this, please post back and let us know what you find out.

vk6kro

It looked like the motor was turning pretty fast, so maybe they stopped the filming and inserted a battery in the wiring. So it would be a hoax. Don't waste your time with it.

You could make a synchronous motor like that, but you couldn't control the magnet accurately enough with your hand.
If all the magnets in the rotor were mounted with north poles facing out then you could attract each one with a south pole and then repel it with a north pole to keep the rotor turning.

BenchTop

If you start out with a rapidly spinning wheel and videorecord it as the dynamic brake of the light slows it to a stop while you hold a carrot nearby, then you can reverse the clip and post it on youtube and get a few people to try wiggling a magic carrot around...lol.
Sometimes the object is selling them the magic carrots to play with.