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From: peters@cubsvax.UUCP
Newsgroups: net.physics
Subject: Re: Consistency in science!?!!?
Message-ID: <144@cubsvax.UUCP>
Date: Mon, 16-Jan-84 15:44:52 EST
Article-I.D.: cubsvax.144
Posted: Mon Jan 16 15:44:52 1984
Date-Received: Wed, 18-Jan-84 01:19:32 EST
References: <15489@sri-arpa.UUCP>
Organization: Columbia Univ Biology, New York City
Lines: 44

You ask why it isn't simple to answer the question why a bottle
of very cold Coke freezes when it's opened.

You raise an interesting point... and in doing so exemplify one of the
common misconceptions about not just physics but science in general:
namely, that simple-sounding "problems" out there in the real world are
simple to solve, and that all scientsts will agree on a solution.  It
ain't that way.

First of all, there are only about a dozen people in the world who know
exactly what is in Coca Cola, and they aren't telling.  So, since 
everything we add to water changes its properties, we have to come up 
with a good guess about what Coke is -- or at least a guess which, though
it may not taste like Coke, has enough in it to explain the properties we 
observe.  This we call a "model."  I used water in my analysis, though
I also pointed out that the dissolved sugar will increase the viscosity
at low temperatures, thereby leading to supercooling.  I used water 
because it's easy to look up things like solubility of CO2 in water,
and hard to find solubility of CO2 in a solution of sucrose in water
at a specific concentration.

And so it goes.  See also net.misc (I believe) for a current discussion
about how mpg relates to mph in driving.  Or net.audio for a current 
discussion about whether digital recording is better/worse/no different
than analog recording, or whether CD's are better/worse/no different than
vinyl discs.  In all these discussions people are putting forth *models*
of the phenomena under discussion, and doing calculations, sometimes
involved ones, to explain why they think their point of view is correct.
Occasionally someone disputes a calculation, but usually the discussion
is about either (a) new data -- that is, someone *observes* a phenomenon
which s/he thinks is relevant, and which s/he feels has been overlooked --
or else (b) whether the model used a basis for calculation really 
includes all the essential aspects of the *physical system* under 
discussion.

Systems which can really be modelled in their entirety exist very
few places outside a laboratory;  experimental science is the art
of devising such systems, and scientists try to devise experiments
for which (a) they know exactly what the result will mean, and (b)
it means something which people care about.  That's tough, and
that's why science is hard.

{philabs,cmcl2!rocky2}!cubsvax!peters
(Peter S Shenkin; Dept of Biol Sci; Columbia Univ; NY, NY 10027; 212-280-5517)