From: Marc Afifi (marc_afifi@yahoo.com)
Date: Wed Sep 27 2000 - 07:49:24 PDT
Message-ID: <20000927144924.6901.qmail@web218.mail.yahoo.com> Date: Wed, 27 Sep 2000 07:49:24 -0700 (PDT) From: Marc Afifi <marc_afifi@yahoo.com> Subject: if ice sank
..what would happen in a pond with
> organisms if ice became denser
> and sank to the pond's bottom???
This is a fun question whose answer usually knocks my
students' socks off. The answer, of course, is that
there would be very little -- if any -- liquid water
on Earth. I assume we are talking about a relatively
deep pond that will have liquid water under the ice
during a normal winter.
It is ice's insulating property that prevents the
freezing solid of the Earth's water. Since cooling
occurs at the surface, if ice sank then the water
would continue to cool and freeze at the surface until
all of the water had frozen. This would happen not
only in ponds but in the oceans as well and
consequently life would be very different indeed. But
because ice slows the cooling of the surface waters by
insulating it from the freezing air, unless there is a
very long and very cold winter there will be liquid
water under the surface. The pond would clearly freeze
solid during an ice age, but in today's climate the
insulating properties of ice is enough to prevent the
pond from freezing solid. It's an interesting thought
experiment.
-Marc
=====
Marc Afifi
Chemistry, AP Chemistry, Physics
Pacific Grove High School
Pacific Grove, CA
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