Fran Scott from the Royal Institution in England looks at the science behind an illusory Jeff Koons “sculpture”. In it, three basketballs sit motionless in a tank of water half way down with no visible means of suspension. This is what it looks like:
Jeff Koon - Three Ball Total Equilibrium Tank
Now an inflated basketball would be full of air (um… by definition) so the fact that they’re underwater at all is unusual. And they couldn’t be filled with rocks because they would sink to the bottom. It’s also not a case of having some strategically positioned supports hiding behind the basketballs; you could walk all the way around the tank.
If you would prefer not to know, don’t watch this: