We all know that when you rotate a bucket of water its surface becomes concave, right? Well, when you do the math, it turns out that the shape of the surface is a paraboloid. Specifically, at a given angular rotation speed ω, the shape of the water’s surface will be y = (ω²⁄2g)x². Here's a beautiful demonstration of theory meeting experiment by Jeff Regester. And here's a lovely practical application of the effect: https://physicsfootnotes.com/liquid-mirror-telescopes/ | Physics Footnotes