Even engineers who know how gyroscopes work (and may actually use them on the job) remain fascinated by them: they simply move in a way that all our senses and experience tell us they shouldn’t.
A gyroscope (which at its most basic means a ring or wheel that spins around a shaft) has some very interesting properties. For one, it resists any force that tries to change the direction in which its axle is pointing. You can actually experience one example of this when riding a bicycle: the angular momentum of the wheels helps to keep you from tipping over, especially at high speed.
What’s even freakier, though, is what’s called precession. This means that the spin axis, instead of moving in the direction it’s being pushed, wants to go at right angles to where it’s supposed to. This means, for instance, that when it’s in motion, you can easily balance one on the tip of your finger or the supplied base.
As gravity tries to pull it down, it instead starts swaying in circles, at least until it loses momentum. In fact, if it’s going fast enough, you can hold it horizontally by one end without the other dropping. The following diagram should make this a little clearer:
(The blue arrow pointing outwards actually means that the disc is spinning – this allows angular velocity to be described as a vector).
While even young children will enjoy this gyroscope toy, it also works well as a stress-relief knickknack or a conversation piece to keep on your office desk. Just have a look at this and it’s easy to see how you can use it both for fun and for stress relief:
Many older people will remember this particular item, first manufactured in 1917, from their own childhood. However, while this particular gyroscope is competitively priced compared to similar ones, this comes at the cost of build quality. The bearings are noisy and far from frictionless, so the longest you should expect this gadget to remain spinning is around a minute.
It’s definitely fun to play with, but you can easily break it by, for example, yanking the starting cord too hard. If you’re a science teacher, you may want to spend a little more on a sturdier product. If, however, you just want to amaze your kids from time to time, this is a winner.