Thursday, February 7, 2013

Magnets and motion


This little machine looks like a lot of fun.  It is really quite clever.  There may be people who want to see it as a perpetual motion machine, which it is NOT, so get that right out of your head.  It does NOT produce more energy than it puts in.  However, what it is is a clever and efficient, fun little gadget that can spin for a very long time on its own.  The basic idea is that the magnet at the top is repelling the magnets on the wheel, and since the ones that are further apart repel less than the ones that are closer together, the wheel will turn toward the wider apart magnets.  When we get to the part where the magnets get closer together again, if we didn't mover the top magnet out of the way, it would likely stop the wheel.  However, they can use the momentum of the wheel to lift the top magnet enough to start the whole process over again.  This means that the initial conversion of potential energy from dropping the magnet (note how the white plastic piece on the side will start it spinning) puts energy into the system that starts it spinning for a long time.
This wouldn't be possible at all without our friend Neodymium which gives us these awesomely strong magnets.  I especially like how this system uses magnets on the top AND bottom that are being bumped by the little bumper thingy to accelerate the wheel both at the top and bottom of the cycle.  I must say that I'm surprised that it ends up spinning around fast enough that the momentum of the wheel to have enough energy to lift the magnet at the top.  Due to friction and/or wearing down of the magnets, it will eventually stop and/or stop working very well.  Still, I certainly wouldn't mind having one of these on my desk kind of like a Newton's Cradle or something like that.  Magnets are cool.

Newton's Cradle - image by DemonDeLuxe (Dominique Toussaint)