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"Revolution"...Magnetic Toy



I've been playing with a new toy called 'Revolution'. It's a kind of
magnetic top. The 'top' is shaped somewhat like an hourglass and
levitates horizontally above a base. A metal point is forced against a
vertical glass plate and you give the top a spin. It will go for several
minutes. The only point of contact being the metal point on the glass.

Two questions:

1) If the top is levitated on interacting magnetic fields, why is there
not some significant "magnetic braking"? Lenz's Law?

2) If given some rocking motion (pitch?)--in addition to spin--the
magnitude of the rocking motion and the rate of spin seem to exchange
back and forth somewhat. That is the rocking decreases and the spin
increases--a kind of coupled oscillator? But what is the mechanism?
There does not seem to be enought friction between the point and glass,
so it must be magnetic/electrical. But then if there is a strong
magnetic interaction why doesn't the thing slow down faster?

Anyone played with one of these?
I got mine from Arbor Scientific. Cat# P3-6000 $13.50 No batteries req'd

Dave
--
* David Simmons St. John's Jesuit High School *
* 5901 Airport Hwy Toledo OH 43615 *
* <dsimmon@uoft02.utoledo.edu> *