Further Slinky Physics

 It has been harder to find good videos on slinky physics than I'd imagined. A few experiments in zero gravity have proved so disappointingly unsurprising that the only person who thought it worth putting online is some grumpy flat-Earther calling for an end to science funding. But the video below from Veritasium, is a cracker. Not only did I not manage to predict what happens when a slinky is dropped at full stretch (in a situation with very few variables) but, having seen it, my explanation for why it happened turns out to be completely wrong. All in all, a very satisfactory watch then (and also clearly all a metaphor for something or other, like all videos of plummeting objects). Details after the vid.

 So: I didn't predict the bottom would remain hanging in the air like Wile E. Coyote. And when it did, I decided what I must actually have seen was the bottom springing back up, and that it only looked stationary because the whole slinky was also falling at exactly the same rate in the opposite direction, but this seemed a remarkable coincidence. And that's because, of course, this is not what was happening at all. Nobody's done anything to the bottom of the slinky, so it's not "springing back up", it's simply staying put, held as before by the elasticity of the slinky above, although the tension is shrinking. Presumably therefore, if you simply lowered the slinky rather than let go, the bottom would still remain in place. But no, hang on, that can't be right... I guess it must be... Until the slackness passes through the slinky to the other end? I suppose... I need to get a slinky.... Oh, do you know what else there are surprisingly few videos of online? Mummenschanz.