Though it has no purpose other than entertainment and is in fact nothing more than a disk that spins, this toy is fascinating. Unless you have a kitten around, it’s sure to be the center of attention in any room.
In physics terms, there are actually two types of rotation going on: the disk spins around an imaginary axis passing through its center of gravity, but this axis also moves in a circle. As the disk itself starts to slow, the movement of the axis of rotation speeds up, making it look as if it’s picking up energy from nowhere.
The mirrored surface produces little friction, so this can go on for quite a while. The base is also slightly dimpled so the disk is less likely to head for the hills.
You can observe the same effect with a coin on a tabletop, but this heavy, 3″ (7½ cm) wide disk is a great deal more impressive and keeps spinning for what seems like forever. It also comes with colorful magnetic stickers for added visual impact.
The base is about 9 inches (23 cm) wide, so this can make a great coffee table conversation piece, but might be a little large for most office desks.
The chrome-plated steel puck is nearly indestructible, but the mirrored base is, well, a mirror, so it will inevitably break if small children are allowed free rein with it.