bitmap@ucbtopaz.CC.Berkeley.ARPA (01/06/84)
Several times, I've had the experience of opening a bottle of
squirt or seven-up and having it turn to slush before my eyes.
After experimenting a bit with a freezer and bottles of soda-pop,
I'm unable to explain what happens to my satisfaction.
1. Supercooling: it can happen when the bottle is chilled at most
a few degrees below 0 C. I would expect the heat of fusion to be
still on the order of 80 cal/gram, while this low amount of
supercooling would seem to account for only a few cal/gram. Even
though it didn't freeze solid, most of it was slush.
2. Cooling from gas expansion: the phenomenon happens fast, before
much gas seems to be released. It is possible that much of the gas
comes out of solution in the form of bubbles, I guess.
Does anyone know what the real cause is? If you want to
experiment, I suggest watching your bottles, as one of mine froze
(and broke) when I left it in the freezer too long.
Bill, UCBNemnich@MIT-MULTICS.ARPA (01/09/84)
From: Bruce Nemnich <Nemnich@MIT-MULTICS.ARPA> My guess would be that the CO2 in solution lowers the freezing point of the mixture. Since much of it comes out of solution when the pressure drops as you pop the cap, the freezing point of the resulting mixture is above the temperature of the liquid. Also, because of the many tiny bubbles forming from CO2 leaving the liquid solution, it doesn't get a chance to form a nice big crystal (freeze solid), and you are left with slush. --bruce
Nemnich%MIT-MULTICS@sri-unix.UUCP (01/09/84)
From: Bruce Nemnich <Nemnich@MIT-MULTICS> My guess would be that the CO2 in solution lowers the freezing point of the mixture. Since much of it comes out of solution when the pressure drops as you pop the cap, the freezing point of the resulting mixture is above the temperature of the liquid. Also, because of the many tiny bubbles forming from CO2 leaving the liquid solution, it doesn't get a chance to form a nice big crystal (freeze solid), and you are left with slush. --bruce