My wife and I will often stick bottles of water in the freezer for a little while, because, well, really cold water is refreshing. A few nights ago, I had done that, and I got to witness a neat phenomenon. When I first removed the bottle from the freezer, the water was still liquid and clear. But after I jostled it, the water almost instantly turned into a frozen slush.
This was a mild example of supercooling. The water was at the freezing point, but crystalization had not started yet. But when I disturbed the bottle, it set off a chain reaction, and the water froze before my eyes. Cool 
(no pun intended)
Neat, a friend at work I think had that happen to him once as well
Yeah, when that happens it is really neat. I first noticed it on 20oz sodas.
cool pun intended.
I had the same phenomenon happen to me almost every morning on holiday in Turkey one summer. Every night we would a couple of bottles of mineral water in the freezer compartment of the fridge in our hotel room so that it would be nice and cold for the next day by the pool. But pretty much every morning, the water would come out still liquid and would suddenly turn to icy slush before our eyes after shaking it.
I even got to play around with it a little to see what affected it.
Sometimes it would crystallise quite slowly, starting at the bottom of the bottle and moving upwards (about 10 seconds to freeze entirely) and sometimes it would go in a flash. I even managed to pour myself a glass of water one morning, then put the lid back on the bottle and give it a shake to form ice crystals.
I found that tap water didn’t do the same thing though, which suggested that the purity of the mineral water was helping it not to crystallise while in the freezer.
It was a lot of fun though watching it freeze every morning. And then the following year, on holiday in Greece, we had the pleasure of being able to see it happen again. Lucky us!
I perfected the same last year as hurricanes came through Florida. Here are some video clips.
http://mudd.homeip.net/hurricaneWater/
I just used tap water. I even drank some and it froze in my mouth. Again, ahem, it’s cool.
Note: that’s no ordinary beer bottle. It’s a plastic beer bottle. Pretty high-tech stuff itself, five layers of special plastic to protect the beer from oxygen.
Can you tell me if there were any tricks? My 7 year old daughter wants to do this as a science experiment and before we start playing around, I’d be happy for some help.
Fred
To Fred Fransen:
Sorry for the long delay. I just now saw your request for more info. This should do it.
http://johnmudd.infogami.com/blog/3j1k
John