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From: pmk@prometheus.UUCP (Paul M Koloc)
Newsgroups: net.physics
Subject: Re: Re: Sub-zero Seltzer!
Message-ID: <206@prometheus.UUCP>
Date: Wed, 1-Jan-86 03:15:35 EST
Article-I.D.: promethe.206
Posted: Wed Jan  1 03:15:35 1986
Date-Received: Thu, 2-Jan-86 04:47:19 EST
References: <601@hou2f.UUCP> <1510@ihlpg.UUCP> <675@kitty.UUCP>
Organization: Prometheus II Ltd., College Park, MD
Lines: 46

> > 1) The increased pressure within the bottle suppressed the 
> > freezing point (as in regelation).  When the pressure was
> > released, the water froze.
> > 2) The dissolved CO2 suppressed the freezing point.  When the
> > gas escaped, the water froze.
> > I think the second effect is the more important one. 
> > Al Tino

> =>Larry Lippman @ Recognition Research Corp., Clarence, NY applauds: <=
> 	You got it - the reason is the presence of dissolved CO2 causing
> freezing point depression; the first reason is NOT a factor other than higher
> pressure causing more CO2 to remain in solution.  The quantitative explanation
> for this phenomenon is expressed through Raoult's Law.

> Bill Tanenbaum - AT&T Bell Labs - Naperville IL  ihnp4!ihlpg!tan
> Try 3) Supercooled liquid - Liquids can be cooled well below
> their freezing points without freezing if there are no imperfections
> present at which freezing can begin.  When the pressure was released,
> the bubbles of CO2 were the "seeds" for ice crystal formation, i.e. 
> freezing.

You got almost all of it!  Another contributing factor is: 4> the 
cooling (temperature drop) induced by the vaporization of the CO2 
from the seltzer water.  That is both the temperature of the fluid 
is lowered and the freezing point is raised. The collision point 
once reached proceeds catastrophically and precipitates further 
state changes. 

  5> The "ice crystal seeds" also work as places to facilitate 
the proliferation of "cavitation regions" for the "explosive
boiling" of the CO2. This greatly enhances the rate at which the 
CO2 expelled, so much so that it contributes to the sudden opacity 
of the solid-fluid-gas mixture and sometimes causes such rapid
expansion that the contents overflow and one might even feel a
kind of bump if the container is being held in hand. 

As a kid I found opening near-freezing bottles of coke fun,
and then sucking the slush out even "funner". 

I think that all 4 or 5? mechanisms contribute, not insignificantly!

+---------------------------------------------------------+--------+
| Paul M. Koloc, President: (301) 445-1075                | FUSION |
| Prometheus II, Ltd.; College Park, MD 20740-0222        |  this  |
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