From: Annedoc <Annedoc@aol.com>
Date: Tue, 28 Apr 1998 22:53:45 EDT
To: pinhole@exploratorium.edu
Subject: Specific Heat of Ice
Wow! I just managed to check my mail in hopes that someone responded to my
question, and I was pleasantly surprised. You are right, Ron, it was the 50%
difference that really puzzled me.
Steve, your explanation of different types of motions contributing differently
to temperature increases was helpful. I'm assuming that is what accounts for
the usual 1 to 10% difference in other solids vs. liquids? Also, I accidently
deleted your second to last response, can you send it again?
My questions about hydrogen bonds are, why does so much less energy go into
breaking hydrogen bonds in solid water, especially if there are 15% more of
them. Is it like a threshold where energy doesn't get absorbed breaking the
bonds until a certain temperature is reached? (Maybe the attempt to break
them sets up this jiggling effect?) What is the strength of hydrogen bonds in
ice? Is this connected in anyway to the molar heat of fusion being so much
less than the molar heat of vaporization? Hope these questions aren't too out
there!
Some of my students are also pursuing the answer and have brought various
explanations in from their parents. One still vague, but possibly on the
right track is, there are 3 vs. 6 of a certain type of vibration mode in solid
vs. liquid water. I guess the extra vibration modes must be of the type that
don't contribute to temperature increases?! Looking forward to hearing more.
Thanks, Anne