Have you seen that huge round-rock ball in Tomorrowland? It’s made out of solid granite and even though it weighs over 12,000 pounds, a child can spin it around easily. How is that even possible?
What is a kugel ball?
There’s actually an official name for these types of attractions or features – they’re called Kugel Fountains or Kugel balls. (Kugel means “sphere” or “ball” in German). They’re all over the world, not just in Disneyland, and are usually found in town squares and science museums. And, of course, kugel balls can be made into different colors with various themes and maps. A “globe” of the earth is a popular one.
Here’s a list of some other Kugel balls or fountains installed in the U.S. and other countries.
Side note: a German poster says that they call these features Kugelbrunnen or sphere fountains. And he’s not sure how Kugel ball found its way into the English language.
The idea is you have to have an almost perfectly round, heavy-rocky sphere (usually granite) that sits on a very thin layer of pressurized water. The water layer is so thin, a credit card would barely slide through it, and it makes the ball almost friction-less.
Since the heavy ball floats on a thin layer of pressurized water, you can move it around easily with just one hand or two. By the same token, you can actually stop the ball from rotating as well.
If you’re interested in a deep and cerebral explanation of the *physics* at work, here’s a scientific explanation: Physics of the granite sphere fountain.
Once again the Disneyland water ball is located in Tomorrowland.