On December 7th, Matt Sparks went to get some bottled water out of his garage. The temperature in the garage was below the freezing point of water, but he noticed that the water in the bottles was still liquid. However, when he moved the water, it instantly froze. He has some videos on his site
showing what happened. They're pretty cool, and if you're not aware of the phenomenon of supercooled water (as I wasn't), you might think there's some kind of trickery involved. But there's not. Matt writes:
These videos were recorded with a Canon Powershot S50 digital camera. They have not be altered in any way, other than to reencode them to xvid from mjpeg to reduce size. I assure you that the liquid you see in them is truly water with nothing added to it. It is straight from the bottle. The bottled water I happened to have was Nestle Pure Life Purified Water.
Some quick googling reveals that supercooling is a well-documented
, though mysterious, behavior of water. What it means is that water, if it contains relatively few impurities, can be cooled to below its freezing point without crystallizing. But if you disturb the water, it instantly crystallizes. I'm tempted to try this experiment, but with the temperature outside in the 60s here in San Diego, I'll have to use my freezer.