All posts by Sarah Webb

the toy that stumped Niels Bohr

I didn’t make it to the Nobel Prize festivities in early December. But my husband’s Ph.D. adviser (a friend of a 2008 laureate) hobnobbed with the Nobel elite. She brought back a couple souvenirs as holiday gifts for members in the lab. First of all, everyone needs their own chocolate Nobel Prize.

yes, you too can have a Nobel prize
yes, you too can have a Nobel prize

But we were really fascinated with the Tippe Top from the Nobel Museum. It’s super simple-looking, rounded on the bottom with a dowel-like rod for a spinner. As it spins, the dowel moves from the tippy-top of the top, until the top spins on the dowel. Little did I know that physicists have been arguing about the mechanics of this toy since Sir Isaac Newton: though simple-looking, the physics and mathematics that explain this behavior are anything but. As a recovering chemist, I love the idea of one of my scientific heroes, Niels Bohr, a man absorbed with the spinning behavior in atoms, was also obsessed with the physics and mathematics of this toy.

The more I watch it, the more fascinating the problem is. The top appears to rotate in a constant direction, but it actually changes directions as it flips, maintaining the appearance of constant rotation in one direction. In keeping with the Bohr connection, the Danes have a fascinating description of the history and the physics behind the top. It’s all about shifts in the rotational axis and the wonders of sliding friction.