Finally, an explanation for that mind-melting chain fountain experiment

We were big fans of the video of that bizarre bead-chain experiment that made the rounds on the internet this summer, but not quite as big fans as John Biggins and Mark Warner, physicists from Cambridge University who have published a journal article explaining just what's going on in the viral video.


In the video from the BBC's Steve Mould, beads seem to propel themselves right up and out of a beaker in a single chain. So just what's going on? Biggins and Warner took a look at the physics of the problem, and found that there are actually a pretty complex set of forces causing the different movements the chain is making.


They made this video explaining just what forces are acting on the chain at different points in its cycle of movement. You can also read their whole paper, published in Proceedings of the Royal Academy A, here.

Via the New York Times

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I don't buy it. A fixed platform can't add energy to a system just by resisting a force (the downward force of the other end of a rotating link). To start an object rotating around its center of gravity uses energy, it doesn't come for free and it doesn't miraculously provide more energy for lifting the whole shebang. It doesn't take less energy to lift a log entirely off the ground if you pull it up by the end than it does if you tie it around the middle. His miraculous "kick" just doesn't make any sense.