Fun with the ideal gas law … frozen beer
Scot send this to me … from Kottke.org on frozen beer.
I learned something terrific yesterday: if you take a really cold but still liquid beer out of the freezer and open it, the beer will freeze within seconds. The freezing trick also works if instead of opening the beer, you give the unopened bottle a sharp rap. The reasons I’ve found online for why the trick works varies slightly for the two cases. According to Daryl Taylor’s site for science teachers, opening the bottle changes the pressure in the bottle and thus lowers the temperature:
Jason didn’t believe that the ideal gas law was really at work here … ah silly humans, of course it is. Hey, I’ve done this myself. The idea is really simple (you could do it with pop I suppose). The carbonated liquid is below it’s freezing point, but the close vessel doesn’t let it really freeze. Now, eventually it will freeze, but in that fragile interim state … it’s close but no cigar. You open it, change the pressure … ice beer!
If you try this, it’s pretty darn amazing to watch. It can happen almost instantly (and maybe a tad messy, but a lot of good science is messy).
Tags: frozen beer, universal gas law
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