I can report experimentally that indeed D2O ice sinks. In addition, I made ice from a 17% H2O + 83% D2O solution, which was almost neutrally buoyant (I was off a bit, and it sank, but clearly was very close to buoyant). On Sep 21, 2005, at 2:11 PM, Schroeppel, Richard wrote:
Remember that the density of water is maximal at 4C, which, by coincidence (?) is the melting point of D2O. Depending on various temperatures, a D2O ice cube could pick up a coating of H2O or HDO ice, which might refloat it.
Rich
-----Original Message----- From: math-fun-bounces+rschroe=sandia.gov@mailman.xmission.com [mailto:math-fun-bounces+rschroe=sandia.gov@mailman.xmission.com]On Behalf Of Michael Kleber Sent: Wednesday, September 21, 2005 12:04 PM To: math-fun Subject: Re: [math-fun] 177 million tons of ice???
Tom Knight meant to write:
The molecular size and charge distribution is almost identical, so the crystals form without distinguishing between H2O and DHO. It would be rare to find any significant number of molecules of D2O.
[I corrected a DH2O to DHO, per later conversation.]
Let's be clear here: heavy water is indeed D2O. You can't have a sample of pure, um, welterweight water, DHO: the hydrogen atoms are exchanged between water molecules all the time, so you'd really have a sample with half DHO and a quarter each H2O and D2O.
Per Steve Gray's density calculation, you would need about (1/.914 - 1)/(20/18 - 1) = "85% heavy" water to make ice the density of normal liquid water.
-- It is very dark and after 2000. If you continue you are likely to be eaten by a bleen.
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