We did something like this in high school as part of our chemistry class. We supercooled the distilled water using a salt/ice bath, taking it well below freezing (in a test tube). Then we introduced a "seed" (don't remember if it was a chip of ice, or a bit of sand, or what) - and watched it "freeze" instantly. I'd have to look at my notes to know what the experiment actually was for, how it was conducted, lab notes, etc - because there was a point to it all (not just as a demonstration of super-cooling and freezing)...
That reminds me of a really cool experiment we did in chemistry. You can create anice packs" that are basically a super-saturated solution that precipitates when you snap a little trigger in the corner of the pouch, creating an endothermic reaction. It was really awesome, and I definitely remember a lot more from experiments like that then I do "titrate [x] in to [y] and take notes" experiments.
Has me thinking of the dangers of drinking vodka outdoors in Siberia, in the winter. Of course any ill effect of the vodka might be considered mercy, in such conditions.
