'Feynman and followers, you guys are off': Physicists disprove decades-old Richard Feynman theory on 'silly' sprinklers

Physicists at NYU have disproved a decades-old theory by Richard Feynman about "reverse sprinklers" — devices that suck water in instead of spraying it out. By building seven unusually shaped sprinklers, researchers found that neither Feynman's nor Ernst Mach's theories correctly explained the rotation. The real answer lies in the sprinkler's central hub, where colliding water generates rotational force — findings that could improve turbine and renewable energy device design.