Looking for a fun toy that’s educational too? I suggest a gyroscope.
Gyroscopes are a common topic in Physics classes. They seem to defy gravity, which is why they are addicting to play with. (Search “gyroscope” on YouTube if you have never seen one in action before.) You can perform many “tricks” with a gyroscope, such as letting it balance on your finger, on a string, or even on another gyroscope!
How do gyroscopes work? If you were to simply stand a gyroscope up on one of its ends, it would fall over when you let go, as you would expect. However, spinning the disc gives the gyroscope angular momentum. Most people understand linear momentum, because it is very intuitive. A large object moving at a given velocity will not change velocity unless there is a net external force, perhaps caused by gravity, air resistance, or friction. This is conservation of momentum. There is also conservation of angular momentum, which is the rotational analog of linear momentum. Angular momentum has a direction, just like velocity. The spinning disc “wants” to keep spinning along the same axis, unless there are external forces that cause a change in the total angular momentum. As a result, if you stand a spinning gyroscope upright, it will remain upright, or at any angle you put it at for that matter, even after you let go (which is why they seem to defy gravity). The pictured gyroscope is spinning. Additionally, the gyroscope will rotate slowly about the pivot point (a movement called precession), which conservation of angular momentum also explains. It’s confusing, but the results are amazing!
Gyroscopes can be a fairly inexpensive toy. I found a twin-pack online for about $10, including shipping and handling. I purchased the “original” model which is made from metal. Newer models have parts made of plastic. They work fabulously, better than the originals, but are twice as expensive and actually look cheaper and less classy, because of the plastic parts. However, my bet is that the models with plastic will continue to perform well even after hundreds of bumps and falls, while the metal version I have already seems to be suffering from a few weeks of use. I might opt for the plastic kind if I were to buy another one in the future, which is likely.
Gyroscopes are addictively fun, yet educational – the perfect combo for a toy.