Twisted Shop Class » Icy Hot
our out some sodium acetate and watch it freeze instantly to make odd sculptures. In his hilarious book Cat's Cradle, Kurt Vonnegut describes a crystal substance, ice-nine, that turns any water it touches into more ice-nine. The inventor spends a day playing with it in his kitchen (before it destroys the world), freezing pots of water with crystals. When I read that passage, I knew exactly what he was talking about, because I've done it myself.
OK , I don't really have any ice-nine. But a common ingredient in hand warmers, sodium acetate, simulates the stuff remarkably well, minus the end-of-the-world-as-we-know-it bit. It can turn a bowl of liquid to a solid in seconds, triggered by the smallest crystal.
The mechanism behind this is supersaturation.