Pull a bit of a long chain out of a container, and you’ll quickly find the beads take on a life of their own, siphoning out of the jar while leaping and looping in the air. Some of the dynamics are clear – the ever-growing free end of the chain has weight enough to pull the rest of the chain out, much like the pressure difference that drives a siphon. But a lot of the rest of the dynamics are unclear and have generated a lot of discussion. It turns out that the same behavior is observed for chain laid out on a horizontal surface (video links on the right of that page) and even the dynamics of that simpler version of the problem are complex. All part of the beauty inherent in Newton’s second law. (Video credit: Steve Mould/Earth Unplugged; Research credit: J. A. Hanna et al.; submitted by Elin R)
Self-Siphoning Stream of Beads
