Re: Density of water.

[Brian Whatcott <inet@INTELLISYS.NET>]

Is there anyone else who thinks the thermal conductivity of ice
 is less than that of water?   <grin>

Brian W

At 10:35 AM 12/3/01, you wrote:
> I don't think (in this unconscionably long thread) anyone has mentioned the
> importance of the insulating quality of ice in protecting aquatic
> life.  This I
> think is the difference between freezing from the bottom up or the reverse.
> However, what ever the conditions (already stated on this thread?) no ocean is
> going to freeze, unless we have an ice age much more intense than the earth's
> ever experienced (barring the creation of the earth before the sun)..
>
> bc
>
> Rick Tarara wrote:
>
> > But once the whole body of water has cooled and mixed to a nice uniform 0.1
> > degree C and then cools a little more----one big ice cube!  Somewhat
> > devastating to temperate (and artic) zone aquatic life and therefore to the
> > diversity of aquatic life, but unless one can cite evidence of
> sustained sub
> > zero global temperatures during the past 2 billion years, then life itself
> > is not necessarily threatened.
> >
> > Rick
> >
> > **********************************************
> > Richard W. Tarara
> > Professor of Physics
> > Saint Mary's College
> > Notre Dame, IN 46556
> > rtarara@saintmarys.edu
> >
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> >
> > ----- Original Message -----
> > From: "Brian Whatcott" <inet@INTELLISYS.NET>
> > To: <PHYS-L@lists.nau.edu>
> > Sent: Sunday, December 02, 2001 9:18 PM
> > Subject: Re: Density of water.
> >
> > > At 12:25 PM 12/2/01, Jim Green wrote:
> > > >At 23:51 01 12 2001 , Bernard C wrote:
> > > > >Right, Hewitt plots (ordinate) the volume of one gram of water instead
> > > > of the
> > > > >inverse.  No matter, he's plotting water not ice.  Ice (normal near
> > zero C
> > > > >[ice I]) 917 kg / m^3 or sg ~ .92  Water @ 100 C is 1.04 mL / g or sg
> > > > 0.96 So
> > > > >ice floats as per your experience (and mine).
> > > >
> > > >Bernard, you seem  to be missing the essential point -- the fact
> > > >that  makes life possible!  Water at freezing is less dense than
> water at
> > > >4C therefore water freezes on the _surface_ of the body of water.
> > > >
> > > >Jim Green
> > > >mailto:JMGreen@sisna.com
> > > >http://users.sisna.com/jmgreen
> > >
> > >
> > > This gee whiz item is a favorite of the divine design folks.
> > >
> > > If water density uniformly decreased above freezing point,
> > > it would cool at the surface of cooler air as usual  - and becoming
> denser
> > > when cooler then sink, until it reached it reached its density level.
> > >   Relatively warmer water at the bottom would rise, and so I suppose,
> > > there might be a vigorous circulation while a temperature gradient
> exists.
> > > And quite possibly on significant bodies of water, there would always
> be a
> > > gradient, and a circulation, so that icing would be postponed perhaps
> > > banished from significant bodies of water....
> > >
> > > This does not seem specially lethal to life, when I consider the life
> that
> > > thrives
> > > in sulphide springs at great depths.

Brian Whatcott
  Altus OK                      Eureka!