The funniest videos to watch backwards are those in which entropy increases a lot: things like explosions and toppling dominoes, where it is completely obvious that the order of the video frames has been reversed. By contrast, something like a bouncing ball is pretty boring to watch backwards.
Tom Stoppard’s play Arcadia features some good discussion of entropy, and reactions that cannot be reversed. It is easy enough to stir jam into pudding, but impossible to unstir it back out. In addition to showing us something about the nature of time in our universe, it is a decent metaphor for why human regret can be counterproductive. You can’t unstir the pudding, after all.
Enterprising geeks have cooked up an entertaining new way to rapidly increase the entropy of a bunch of popsicle sticks or tongue depressors. It’s like a more energetic version of dominoes, and well worth a look both forwards and backwards.
