Re: Does ice contract when cooled to a certain level?

Yes, the normal state of affairs is for water to contract when it is 
cooled at constant pressure; it is just the small region of the liquid 
below 4 degrees C that is the exception.  The reason for the exception is 
that ice has an "open" structure that is less dense than liquid water.  As 
you get close to the freezing point, the water starts to get a little 
icelike so it expands slightly.  Then it expands a lot when it freezes, 
but if you then cool the solid ice further it contracts like most solids.

Here is a table of the volume (in cubic centimeters) occupied by 1 gram of 
water at atmospheric pressure at various temperatures:

Temperature (deg C)   Volume (cm3/g)
90                    1.035937
70                    1.022741
50                    1.012110
40                    1.007845
30                    1.004370
20                    1.001796
10                    1.000298
5                     1.000033
4                     1.000025
2                     1.000057
0 (liquid)            1.000157
0 (ice)               1.09089
-10                   1.08914
-20                   1.08748
-30                   1.08588

As for your question about the temperature at the polar caps, I don't know 
except to say it is usually quite cold.  I suggest you resubmit that under 
the Earth Sciences category, or possibly with a search on the Web you 
might find information on the U.S. research station at the South Pole.

Allan Harvey, aharvey@boulder.nist.gov
"Don't blame the government for what I say, or vice-versa."