Pressure (not heat) of fusion of water
Hoop...@aol.com
Water is a unique substance in that it expands when it freezes. How does one
calculate the amount of pressure exerted by water as it is converted to ice?
For example, if I confine the water to a closed container, then cool it to
below freezing, what is the pressure exerted on the walls of this closed
container?
Uncle Al
PVT phase diagram. Water is rich with phases vs T and P so you must
be very guarded in using equations of state.
P (bar) T (C)
================
1.01325 0.0026
100 -0.7410
200 -1.5166
300 -2.3206
500 -4.0156
800 -6.790
1000 -8.803
P=100 MPa, T=-9.0C
P=29,990 psi, T=-22c
--
Uncle Al
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)
Danny Ross Lunsford
> Water is a unique substance in that it expands when it freezes. How
> doesone calculate the amount of pressure exerted by water as it is
> converted to ice? For example, if I confine the water to a closed
> container, then cool it to below freezing, what is the pressure
> exerted on the walls of this closed container?
What an interesting question! Here's a first guess - because water is more
or less incompressible, the pressure exerted on a closed vessel is *whatever
it needs to be* to break the vessel. I've never seen the experiment tried,
but I'm betting you could encase water in the hardest, toughest alloy of
titanium, and the water on freezing would split it open like a melon rind.
Of course, at extremely high pressure, states of matter blur into each
other - so if we imagine the water encased in some ideal container that can
withstand any amount of pressure, the water would probably never freeze, but
remain a supercooled liquid. Think of an ice skater - the pressure exerted
on the ice by the skate blade forces it to liquefy, and that is why ice
skating is possible. The skate rides on a "cushion" of pressure-induced
water.
Here's an interesting link about applying extremely high pressure to prevent
the formation of ice crystals - the application is cryonic preservation of
life :)
http://www.benbest.com/cryonics/pressure.html
[Moderator's note: as water freezes, the pressure is not "*whatever it
needs to be* to break the vessel", since this would imply that ice is
completely incompressible. You can compress ice as much as you like
with sufficiently high pressures, and at least 11 different crystal
forms are known:
http://skua.gps.caltech.edu/hermann/ice.htm
At 43,400 times normal atmospheric pressure, it becomes a cubic
lattice with density 2.51 grams/cm^3 in which individual water
molecules no longer exist! Ice is cool. - jb]
Graham Rounce
"Danny Ross Lunsford" <antima...@sbcglobal.net> wrote in message
news:3NNC9.3434$%9.1345...@newssvr12.news.prodigy.com...
> ... an ice skater - the pressure exerted on the ice by
> the skate blade forces it to liquefy, and that is why ice
> skating is possible. The skate rides on a "cushion" of
> pressure-induced water.
That's a bit of a myth, apparently. There's a film of ice/water on the
surface of the ice, and that's what the skate slides on.
Graham Rounce
Daniel Grubb
Suppose you had 1cc of water and brought it down to the freezing point.
Suppose also that it is a container. Well, at the freezing point, it would
try to expand. By how much? I don't recall exactly, but let's say it
would expand to 1.05cc. Now, how much pressure does it take to compress
that 1.05cc down to 1cc again? I don't know this either, but it is related
to Young's modulus for water. You just have to compute how much pressure
gives a compression of that .05cc. This will be the pressure exerted on
the container. Of course, if the container cannot withstand that pressure
due to it's own properties, the container bursts.
--Dan Grubb
Toby Bartels
[a bunch of stuff that I cut]
>[Moderator's note: [...] You can compress ice as much as you like
>with sufficiently high pressures, and at least 11 different crystal
>forms are known: <http://skua.gps.caltech.edu/hermann/ice.htm>.
>At 43,400 times normal atmospheric pressure, it becomes a cubic
>lattice with density 2.51 grams/cm^3 in which individual water
>molecules no longer exist! Ice is cool. - jb]
I see (in Figure 2) ice IX down there below -100 degC around 0.3 GPa.
I guess that it's not likely to be much of a threat in the real world.
^_^
-- Toby
Frisbie Einstein
>
> [Moderator's note: You can compress ice as much as you like
> with sufficiently high pressures, and at least 11 different crystal
> forms are known
Quite so. Some of these forms can be observed in nature here on
earth. Ice that has been compressed by a glacier can be a beautiful
torquoise blue.
Jean-Bruno Brzoska
"Graham Rounce" <gra...@rounce.freeserve.co.uk> wrote
I think we don't know if pressure melting in skiing is a myth or not.
Sam Colbeck wrote a monograph on the subject (CRREL report 92-2, probably
available on line on their website).
Basically, a good slide is obtained when a transient liquid film
of significant thickness appears under the skate or
ski. Experimentally, a smoothing mark is observed behind a skate or
ski that slides correctly. If the mark can be seen in visible light,
the cause of the mark (temporarily melting) is at least
micron-size. Ellipsometric measurements by Dash and other people from
Seattle (about 6 years ago) showed that the surface liquid layer is
mostly a few nanometers thick, and would grow micron size only well
above -0.1 degC. Remember that +/- 0.1 degC is often within the
accuracy of thermometers...
There is probably a superposition of pressure melting (for
instance, ice melts at -2 degC under 300 bar) and frictional heating
(of the order of 100 W for skiing at 10 m/s: about 100 W/m2,
comparable to sun heating in aver age conditions).
In both cases, the melting takes place only on grains that are in
contact with the ski or skate: when excess water is formed it is
expelled by the slider. The only conceptual difference is that
frictional heating implies heat diffusion across the ice (then time
constants), whereas isothermal pressure melting ceases when the stress
is removed and does not alter the temperature profile in ice. The
former has a cumulative effect during the contact time, and the second
has not.
Moreover, if there is static pressure melting (compact grains and T
close to 0 degC), frictional heating is only hydrodynamic (viscous), and
should tend to 0 when V->0. On the contrary, in colder conditions, ice
should be brought to higher T to make melting possible... by frictional
heating, and good sliding (on a liquid film) will be observed only at
moderate or high speed. I would try to summarize like that:
Low V, high T: Good, pressure melting
High V, high T: Good, pressure+frictional melting
Low V, low T: Bad, solid frictional heating
High V, low T: Fair to good, frictional melting
Of course it is different at 0 degC for high LWC: in this case,
suction of liquid water may dissipate a lot of energy (like cycling on
a wet road). For these conditions, ski and wax makers generally try
to obtain large contact angle, drops and bubbles to reduce viscous
dissipation in liquid water: smooth hydrophobic wax, sometimes furrows
to avoid trapping bubbles.
Thanks by advance for your scientific comments or corrections.
jean-bruno
Doug Goncz
>I've never seen the experiment tried,
>but I'm betting you could encase water in the hardest, toughest alloy of
>titanium, and the water on freezing would split it open like a melon rind.
Nope. The work doable by the water is precisely the heat removed to change its
phase, and no more.
An email copy of your post is welcome.
Yours,
Doug Goncz, Replikon Research, Seven Corners, VA (remove pee dot mil antispam)
http://users.aol.com/DGoncz
http://groups.google.com/groups?as_q=DGoncz
"Function, Funding, Form, Fit, and Finish"
John Baez
Frisbie Einstein <patmp...@hotmail.com> wrote:
> John Baez wrote:
>> You can compress ice as much as you like
>> with sufficiently high pressures, and at least 11 different crystal
>> forms are known [...]
>Quite so. Some of these forms can be observed in nature here on
>earth. Ice that has been compressed by a glacier can be a beautiful
>turquoise blue.
But is it really a different crystal form? The website I mentioned:
http://skua.gps.caltech.edu/hermann/ice.htm
says "All of the natural ice on earth is hexagonal ice, ice Ih, as
manifested in six-cornered snow flakes. At lower temperatures and
at pressures above 2 kbar many other ice phases with different
crystalline structures exist."
Two kilobars is almost 2000 times standard atmospheric pressure,
which is apparently the pressure that would be created by 20,000
meters of water:
http://www.speckdesign.com/Tpressure.html
That seems way too much to be attained in a glacier. So, I think
the beautiful blue of glacier ice might simply be due to the fact
that all the air bubbles have been squeezed out.
I like the picture here of ice Ih and ice Ic:
http://skua.gps.caltech.edu/hermann/ice.fig1.html
The website says:
"If water vapor is condensed on a cold substrate between -80 C and
-130 C, a cubic modification, ice Ic, is formed. Ice Ic is related
to ice Ih in the same way as cubic diamond is related to hexagonal
diamond, the cubic and hexagonal forms having almost the same density.
Below -130 C a noncrystalline amorphous solid known as low-density
amorphous ice, ice aI, appears. A high-density amorphous phase, ice
aII, with a density of 1.31 Mg/m3 can be made at 77 K by compressing
ice Ih to 10 kbar."
I didn't even know there were two crystalline forms of diamond!
Russell Blackadar
[snip]
> Suppose you had 1cc of water and brought it down to the freezing point.
[snip]
For the rest of your answer to be correct, this needs to be
the freezing point *at the pressure which is finally reached*.
With addition of that important proviso, your answer is a
good one.
Another way of putting it is, we can't tell what pressure will
be reached until someone specifies the temperature. Btw note,
at precisely 0 Celsius this problem has an easy answer.
Doug Goncz
> you could encase water in the hardest, toughest alloy of
>titanium, and the water on freezing would split it open like a melon rind.
Nope. The work doable by the water is precisely the change in heat content.
Measuring all this is another story. That is, accounting. But the second law of
thermodynamics would seem to apply, and I am about to take a class to see if it
does.
Squark
> All of the natural ice on earth is hexagonal ice, ice Ih, as
> manifested in six-cornered snow flakes. At lower temperatures and
> at pressures above 2 kbar many other ice phases with different
> crystalline structures exist.
One easy way to get an alternative ice seems to be mixing water and
liquid nitrogen (one has to keep the proper proportions for it to
work, figurally speaking; figurally because it's not really the
proportions that matter, of course). The result is round pieces of
very white, non-transparent ice. It looks as if it's different
crystalline form, I've never gotten a confirmation of it though.
Is it now?
Best regards,
Squark
------------------------------------------------------------------
Write to me using the following e-mail:
Skvark_N...@excite.exe
(just spell the particle name correctly and use "com" rather than
"exe")
J. J. Lodder
> John Baez <ba...@galaxy.ucr.edu> wrote:
>
> says "All of the natural ice on earth is hexagonal ice, ice Ih, as
> at pressures above 2 kbar many other ice phases with different
> crystalline structures exist."
Indeed, and (thanks to Kurt Vonnegut, Cat's Craddle)
it is Memorable that there are Nine of them,
Jan
--
"Nothing in this book is true." (Kurt Vonnegut)
Uncle Al
John Baez wrote:
>
> In article <ac4e6c8f.0211...@posting.google.com>,
> Frisbie Einstein <patmp...@hotmail.com> wrote:
>
> > John Baez wrote:
> I didn't even know there were two crystalline forms of diamond!
Cubic diamond is the usual polymorph, corresponding to all chair
cyclohexane rings. Lonsdaleite is hexagonal diamond, containing boat
cyclohexanes (a higher energy conformer),
http://cst-www.nrl.navy.mil/lattice/struk/hexdia.html
It is formed by shock compression of oriented graphite.
We've looked at forming a lattice from twist cyclohexane rings. The
solid angles don't add to a space-filling lattice. Carbon allotropes
also include buckeyballs and nanotubes, and the hypothetical bulk
polycarbyne (-C#C-)n where "#" is a triple bond.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
Ken Muldrew
fii...@yahoo.com (Squark) wrote:
>One easy way to get an alternative ice seems to be mixing water and
>liquid nitrogen (one has to keep the proper proportions for it to
>work, figurally speaking; figurally because it's not really the
>proportions that matter, of course). The result is round pieces of
>very white, non-transparent ice. It looks as if it's different
>crystalline form, I've never gotten a confirmation of it though.
>Is it now?
No, it's just hexagonal ice but it's full of microscopic gas bubbles
and grain boundaries that scatter light. The gas bubbles are
encapsulated within the ice due to the fast freezing rate and make it
opaque. Also, if you want to make this easier to do (so the
proportions aren't quite so important), pump down the nitrogen first
so that you have a slush. This has much better heat transfer
properties.
Ken Muldrew
kmul...@ucalgary.ca
obirer
"Jean-Bruno Brzoska" <jean-brun...@meteo.fr> wrote in message news:<arimos$cbv$1...@mi.cerfacs.fr>...
Common Theory of Ice Skating is all Wet!
Water has many unusual properties. One is that the low pressure solid
form (what we know as ice) has a volume per mole that is ~10% larger
than that of liquid water into which it melts. An everyday consequence
of this fact is that ice cubes float near the surface of water, with
about 10% of their volume above the water-air surface and 90% below.
Another consequence of this decrease in volume upon melting is that
the melting temperature of ice decreases when one increases the
pressure on the ice. This can be rationalized by Le Châtelier's
Principle. An increase in pressure on a sample of ice can be partially
removed by melting the ice and thus lowering the sample volume.
However, the effect is a small one in that it takes a pressure of ~121
atmospheres (1.22 MPa in SI units) to reduce the melting temperature
by a mere 1 degree Centigrade.
It is often claimed that one can skate on ice because the pressure of
the skate causes the ice to melt, thus dramatically reducing the
friction between skate and ice. While this makes a good story, it is
not quite correct. If one takes the skater to have a mass of 75 kg
(weight of 165 lbs), and the skate to be 3 mm wide and 20 cm long, one
can calculate that entire gravitational force exerted on the area of
one skate is only a pressure of about 12 atmospheres. While one can
imagine that the force is concentrated in a somewhat smaller area, the
effect of pressure alone is clearly enough to shift the melting
temperature of the ice by at most a few tenths of a degree. Since
common experience is that ice skating is possible even when the
ambient temperature is well below the normal freezing point, the
pressure induced lowering of the melting point clearly does not
explain this every day observations.
What is responsible then? Scientists have far from a complete
understanding of this everyday phenomenon. It is likely partially
related to an effect known as surface melting. The stability of solids
is due to the regular structure that allows for each molecule to have
multiple attractive interactions. At the surface of a solid, this is
not the case, since there are no molecules 'above' the surface to bind
to. As a result, the surface molecules will often distort to make the
best of a bad situation by trying to increase their bonding to each
other and those below. This is known as surface reconstruction. It is
also known that the molecules on the surface can become disordered and
liquid like at a temperature below the normal melting point of a
solid, this is the phenomenon known as surface melting. Bringing up
another surface (such as the metal of a skate) will influence this
surface melting, since now the water molecules on the surface can bind
to the metal surface atoms as well. Another important effect is
friction, which can generate enough heat to melt a thin layer of ice
in contact with the skate.
from Kevin Lehmann's Bad Chemistry Page
http://www.princeton.edu/~lehmann/BadChemistry.html
John Devers
>
> I didn't even know there were two crystalline forms of diamond!
Hi JB, did you hear about this one?
Structure of a New Dense Amorphous Ice
http://link.aps.org/abstract/PRL/v89/e205503
Ice that sinks in water.
http://www.aip.org/enews/physnews/2002/split/612-3.html
Ps. When I posted this news on another forum someone posted a story
about Ice-nine and a Dr. Breed creating some and passing it on to his
children. Is there any truth in that story?
John Baez
J. J. Lodder <jjll...@xs4all.nl> wrote:
>> John Baez <ba...@galaxy.ucr.edu> wrote:
>> "All of the natural ice on earth is hexagonal ice, ice Ih, as
>> manifested in six-cornered snow flakes. At lower temperatures and
>> at pressures above 2 kbar many other ice phases with different
>> crystalline structures exist."
>Indeed, and (thanks to Kurt Vonnegut, Cat's Cradle)
>it is Memorable that there are Nine of them [....]
At least 11 crystal forms of ice are known now:
ice Ih, ice Ic, ice II, ice III, ice IV, ice V, ice VI,
ice VII, ice VIII, ice IX, ice X and ice XI.
There are also two amorphous forms: ice aI and ice aII.
Again, this is a fun place to learn about them:
http://skua.gps.caltech.edu/hermann/ice.htm
There are also some claims about ice XII:
C. Lobban, J.L. Finney, W.F. Kuhs,
The structure of a new phase of ice,
Nature 391 (15 January 1998), 268-270.
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v391/n6664/abs/391268a0_fs.html
I presume that when Vonnegut wrote his famous tale concerning
a form of ice more stable than liquid water room temperature,
scientists had not yet discovered ice IX, leaving Vonnegut
free to use this name in his story:
There are several ways," Dr. Breed said to me, "in which certain
liquids can crystallize -- can freeze -- several ways in which
their atoms can stack and lock in an orderly, rigid way."
That old man with spotted hands invited me to think of the several
ways in which cannonballs might be stacked on a courthouse lawn,
of the several ways in which oranges might be packed into a crate.
"So it is with atoms in crystals, too; and two different crystals
of the same substance can have quite different physical properties."
"Now suppose," chortled Dr. Breed, enjoying himself, "that there were
many possible ways in which water could crystallize, could freeze.
Suppose that the sort of ice we skate upon and put into highballs --
what we might call ice-one -- is only one of several types of ice.
Suppose water always froze as ice-one on Earth because it had never
had a seed to teach it how to form ice-two, ice-three, ice-four...?
And suppose," he rapped on his desk with his old hand again, "that
there were one form, which we will call ice-nine -- a crystal as
hard as this desk -- with a melting point of, let us say, one-hundred
degrees Fahrenheit, or, better still, a melting point of one-hundred-
and-thirty degrees."
Note to another questioner: no, this story is not true! It would
be incredibly unlikely for the water on earth to have been in a
metastable state for all these years, just waiting for a seed crystal.
Disasters like ice-nine and the accidental destabilization of the
vacuum by quark-gluon plasma experiments at Brookhaven are not
the disasters we need to worry about; if they were possible, it's
almost certain they would have already happened naturally, without
our help. If we want to worry, we should worry about the many
processes we are catalyzing that are too complicated to occur
without our assistance.
J. J. Lodder
In article <3dde98d5....@news.ucalgary.ca>,
Ken Muldrew <kmul...@ucalgary.ca> wrote:
> fii...@yahoo.com (Squark) wrote:
Yesterdays 'rough science' (on BBC2) had the team
trying to make an ice lens as a means to generate heat.
They tried both a bowl,
and a rubber balloon shaped with a hoop in it.
The result was hopelessly clouded in both cases
despite their having boiled the water for a long time.
Is it actually feasible to make a useful ice lens?
Are tales of travelers in the cold
having done so to save themselves fairy tales?
And yes, I do know how they make the very clear 'ice cubes'
on display in whisky commercials:
Gurl ner znqr bs cynfgvp.
Best,
Jan
John Baez
John Baez <ba...@galaxy.ucr.edu> wrote:
>At least 11 crystal forms of ice are known now:
>ice Ih, ice Ic, ice II, ice III, ice IV, ice V, ice VI,
>ice VII, ice VIII, ice IX, ice X and ice XI.
^^^^^^
whoops!
Sorry, I meant to stop at ice X, which is
the 11th and final crystal form of ice listed in this chart:
http://skua.gps.caltech.edu/hermann/ice.table1.html
>There are also some claims about ice XII:
>
>C. Lobban, J.L. Finney, W.F. Kuhs,
>The structure of a new phase of ice,
>Nature 391 (15 January 1998), 268-270.
>http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v391/n6664/abs/391268a0_fs.html
In the abstract they don't actually call it ice XII
or even ice XI; they just call it a twelfth crystal form of ice.
However, in his webpage:
http://www.cmmp.ucl.ac.uk/people/finney/soi.html
J.L. Finney does speak of ice XII, and writes:
[...] the phase diagram is still not fully understood. On
several occasions during the last 15 years, powder lines
have been seen that could not be identified with any known
ice or clathrate phase. As we have pinned down with
increasing precision the preparation conditions we have
begun to back them into a corner. The first success has
been ice XII, a totally new structure that we have found
within the stability region of ice V and which was prepared
by crystallisation from the liquid phase. The topology of
ice XII is unlike any of the known ice phases, and contains
a mixture of 5 and 7 membered rings.
He doesn't seem to talk about ice XI.
Eric Gisse
wrote:
>ba...@galaxy.ucr.edu (John Baez) wrote in message news:<arkbf3$r9u$1...@glue.ucr.edu>...
>> All of the natural ice on earth is hexagonal ice, ice Ih, as
>> manifested in six-cornered snow flakes. At lower temperatures and
>> at pressures above 2 kbar many other ice phases with different
>> crystalline structures exist.
>
>One easy way to get an alternative ice seems to be mixing water and
>liquid nitrogen (one has to keep the proper proportions for it to
>work, figurally speaking; figurally because it's not really the
>proportions that matter, of course). The result is round pieces of
>very white, non-transparent ice. It looks as if it's different
>crystalline form, I've never gotten a confirmation of it though.
>Is it now?
Neat. Ill have to try that.
Could it be that when the ice was formed, that many tiny bubbles of
nitrogen were trapped in it, and the result was simply something
opaque? Cracks or other deformations in ice are not clear.
Have you tried melting the balls and seeing if gas comes out?
Jo Stoller
>Btw note, at precisely 0 Celsius this problem has
>an easy answer.
Surely it is easiest at 0.01 celsius?
Ken Muldrew
ba...@galaxy.ucr.edu (John Baez) wrote:
> "Now suppose," chortled Dr. Breed, enjoying himself, "that there were
> many possible ways in which water could crystallize, could freeze.
> Suppose that the sort of ice we skate upon and put into highballs --
> what we might call ice-one -- is only one of several types of ice.
> Suppose water always froze as ice-one on Earth because it had never
> had a seed to teach it how to form ice-two, ice-three, ice-four...?
> And suppose," he rapped on his desk with his old hand again, "that
> there were one form, which we will call ice-nine -- a crystal as
> hard as this desk -- with a melting point of, let us say, one-hundred
> degrees Fahrenheit, or, better still, a melting point of one-hundred-
> and-thirty degrees."
Life imitates art. In the Correspondence section of the October 11,
1969 issue of Nature, the following letter appeared under the heading,
"Anomalous" Water:
SIR, A report on the properties of "anomalous" water appeared
recently in Nature (222, 159; 1969). The probable structure of this
phase was reported by Lippincott et al.1 who refer to the phase as
polywater, a terse descriptive of the structure.
The properties of polywater are negligible vapour pressure, density
~1.4 g/cm3, partial miscibility with normal water (depending on the
length of the polymer chains) and stability to temperatures ~500°C.
The polymer chains are some 250-420 kJ/mole (60-100 kcal/mole) of
monomer more tightly bound than normal water.
I need not spell out in detail the consequences if the polymer phase
can grow at the expense of normal water under any conditions found in
the environment. Polywater may or may not be the secret of Venus’s
missing water. The polymerization of Earth’s water would turn her into
a reasonable facsimile of Venus.
There are examples of phases in other systems which are difficult to
nucleate. Once the nuclei are present, the phases grow readily, often
by mechanisms other than those required to form the nuclei. It is
almost a truism that, under conditions where both a stable phase and a
metastable phase may form, the metastable phase forms first. In this
case the metastable phase would be normal water.
After being convinced of the existence of polywater, I am not easily
persuaded that it is not dangerous. The consequences of being wrong
about this matter are so serious that only positive evidence that
there is no danger would be acceptable. Only the existence of natural
(ambient) mechanisms which depolymerize the material would prove its
safety. Until such mechanisms are known to exist, I regard the polymer
as the most dangerous material on earth.
Every effort must be made to establish the absolute safety of the
material before it is commercially produced. Once the polymer nuclei
become dispersed in the soil it will be too late to do anything. Even
as I write there are undoubtedly scores of groups preparing polywater.
Scientists everywhere must be alerted to the need for extreme caution
in the disposal of polywater. Treat it as the most deadly virus until
its safety is established.
Yours faithfully,
F.J. DONAHOE
Wilkes College,
Wilkes-Barre,
Pennsylvania 18703, USA.
1 Lippincott, E.R., Stromberg, R.R., Grant, W.H., and Cessac, G.L.
Science, 164, 1482 (1969).
***
For anyone interested in the hornets nest that was stirred following
this letter, consult the book _Polywater_ by Felix Franks.
Ken Muldrew
kmul...@ucalgary.ca
Anonymous Coward
johnd...@froggy.com.au (John Devers) wrote in message news:<2978f9d5.02112...@posting.google.com>...
>
>
> Ps. When I posted this news on another forum someone posted a story
> about Ice-nine and a Dr. Breed creating some and passing it on to his
> children. Is there any truth in that story?
>
This story is from the novel "Cat's Cradle" by Kurt Vonnegut,
a work of *ficton* (I hope you were just joking in the above
PS.) See for example:
http://hypertextbook.com/physics/matter/polymorphs/ice-nine.txt
Uncle Al
> > [Moderator's note: You can compress ice as much as you like
> > with sufficiently high pressures, and at least 11 different crystal
> > forms are known [....]]
> Quite so. Some of these forms can be observed in nature here on
> earth. Ice that has been compressed by a glacier can be a beautiful
> torquoise blue.
Clean bulk H2O is always blue due to near-infrared overtones of
hydrogen bond vibrations absorbing in the deep red,
J. Opt. Sci. Am. 41 304 (1951)
There is an absorption coefficent of 0.01 cm^(-1) right at the edge of
the visible, 700 nm. It is still pulling 0.001 cm^(-1) at 630 nm.
Ice has pretty much the same hydrogen bonds, very slightly
blue-shifted.
Michael Hudson
> Ps. When I posted this news on another forum someone posted a story
> about Ice-nine and a Dr. Breed creating some and passing it on to his
> children. Is there any truth in that story?
This is from Kurt Vonnegut's Cat's Cradle, a novel, so, no.
Cheers,
M.
Jean-Bruno Brzoska
event, especially with fresh (aerated) water. Such water is almost saturated
with gases from air (mainly 02, more soluble than N2), whose solubility is
much higher in the liquid than in the solid. Ahead a freezing front, a
supersaturated zone exists in the supercooled region of the liquid phase;
the level of supersaturation depends on the front velocity. If it is high
enough, bubbles can nucleate; once nucleated, they are trapped in the
advancing solid phase (nice work 5 years ago from GPS-Universite Paris7).
The higher the front velocity, the smaller the bubbles (a few years ago we
used a voluntarily rapid refreezing of water in wet snow to visualize the
former water menisci). On the contrary, the slow radiative cooling of a pond
at night produces clear ice (although polycrystalline). For intermediate
freezing rates, bubbles often gather along grain boundaries; much later and
under hydrostatic pressure, then can finally gather at point jenctions
between grain boundaries and stay there for millenia, providing the well
known "climatic archive".
To pull large ice monocrystals, techniques derived from silicon technology
were applied successfully (CRREL Hanover, LGGE Grenoble, maybe in Japan). To
my knowledge, "clean room" requirements are much less demanding.
jean-bruno
"Eric Gisse" <kseggR...@uas.alaska.edu> a écrit dans le message de news:
q04ttuo8ls186pjan...@4ax.com...
John Devers
ba...@galaxy.ucr.edu (John Baez) wrote in message news:<arsms9$b9d$1...@glue.ucr.edu>...
>
> Sorry, I meant to stop at ice X, which is
> the 11th and final crystal form of ice listed in this chart:
Hi Jb, this quote from the link in my earlier post mentions 13 forms,
maybe an update is needed?
"To date, 13 different forms of crystalline water ice (each varying,
to some degree, in its internal structure) have been identified.
As for amorphous ices, in which the molecules don't adopt a regular
array, a fifth type was recently discovered."
J. J. Lodder
John Baez wrote:
> In article <1fm20uh.epg...@de-ster.xs4all.nl>,
> J. J. Lodder <jjll...@xs4all.nl> wrote:
> >> John Baez <ba...@galaxy.ucr.edu> wrote:
> >> "All of the natural ice on earth is hexagonal ice, ice Ih, as
> >> manifested in six-cornered snow flakes. At lower temperatures and
> >> at pressures above 2 kbar many other ice phases with different
> >> crystalline structures exist."
> >Indeed, and (thanks to Kurt Vonnegut, Cat's Cradle)
> >it is Memorable that there are Nine of them [....]
> At least 11 crystal forms of ice are known now:
> ice Ih, ice Ic, ice II, ice III, ice IV, ice V, ice VI,
> ice VII, ice VIII, ice IX, ice X and ice XI.
> There are also two amorphous forms: ice aI and ice aII.
> I presume that when Vonnegut wrote his famous tale concerning
> a form of ice more stable than liquid water room temperature,
> scientists had not yet discovered ice IX, leaving Vonnegut
> free to use this name in his story:
snip
And Vonnegut goes on to fall into a trap that is as old as SF:
The belief that undercooled water will freeze solid
with the introduction of a seed.
Jules Verne already has an ocean freeze solid instantaneously
and I have been told that Brian Aldiss has the same mistake
as a dramatic device somewhere in his Helliconia series.
There must be others.
Actually, the phase transition liberates far more heat
than can be stored by undercooling.
With the introduction of the seed only a small fraction
of the water will freeze, warming the rest to the melting point.
Eating Ice-nine would not kill by freezing you solid:
it would kill by warming you to its melting point.
Best,
Jan
Squark
> Could it be that when the ice was formed, that many tiny bubbles of
> nitrogen were trapped in it, and the result was simply something
> opaque? Cracks or other deformations in ice are not clear.
I don't know. I do know one guy who seems to be a solid state expert
who claims this ice _is_ a different crystalline form. I haven't
figured out what makes him so sure yet, though.
One small remark: the resulting ice pieces also posses a somewhat
unusual rounded shape.
> Have you tried melting the balls and seeing if gas comes out?
Hmm, no, I don't think so. How do you suggest detecting the gas,
though?
Squark
> And yes, I do know how they make the very clear 'ice cubes'
> on display in whisky commercials:
> Gurl ner znqr bs cynfgvp.
Can you translate that one? :-)
Best regards,
Squark
------------------------------------------------------------------
Write to me using the following e-mail:
Skvark_N...@excite.exe
(just spell the particle name correctly and use "com" rather than
"exe")
[Moderator's note: Its rot13 for "they are made of plastic." -TB]
John Devers
Hi jb, I count 13 on that site too, did I miss something and is the
VHDA from my link included in this list.
1. Ih Hexagonal
2. Ic Cubic
3. aI Amorphous
4. aII Amorphous
5. II Rhombohedral
6. III Tetragonal
7. IV Rhombohedral
8. V Monoclinic
9. VI Tetragonal
10. VII Cubic
11. VIII Tetragonal
12. IX Tetragonal
13. X Cubic
Edward Ruden
"John Baez" <ba...@galaxy.ucr.edu> wrote
> .... It would
> be incredibly unlikely for the water on earth to have been in a
> metastable state for all these years, just waiting for a seed crystal.
> Disasters like ice-nine and the accidental destabilization of the
> vacuum by quark-gluon plasma experiments at Brookhaven are not
> the disasters we need to worry about; if they were possible, it's
> almost certain they would have already happened naturally, without
> our help.
One must be singularly careful about retroactively assessing the a priori
(intrinsic) odds of having avoided a catastrophic event (ice-nine freeze
over, vacuum decay, etc..) based soley on the fact that we have, in fact,
survived it. It can always be argued that perhaps life is astronomically
rare, and our having avoided it is just one of many unlikely
events/nonevents which, had it been otherwise, we would not be here (search
Rare Earth Hypothesis or, alternately, Weak Anthropic Principle).
A purely empirical assessment of the the odds of having survived such an
event must be based on a sample set uncorrelated with the history of earth.
Regular ice seems to be the rule in our solar system, but with all
interplanetary migration of material that occurs (Mars meteorites and such),
an extrasolar census to determine bounds on the likelihood of an ice-9
catastropy would be more convincing. Has ice of any sort ever been detected
in other star systems? I don't recall any such reports.
Meanwhile, assessing the future risk of vacuum decay emprically is
impossible since it presumably propagates at the speed of light and,
therefore, no uncorrelated observation is possible.
Edward L. Ruden
John Baez
John Devers <johnd...@froggy.com.au> wrote:
In my post, I said there were 11 crystal forms of ice listed
on this website:
http://skua.gps.caltech.edu/hermann/ice.htm
You just confirmed this by listing these 11 crystal forms.
I also said there were 2 amorphous (i.e. noncrystalline) forms
of ice on this website. You just listed those, too!
So, there's no conflict here.
It's true that the other website you discovered:
http://www.aip.org/enews/physnews/2002/split/612-3.html
mentions 13 crystal forms and 5 amorphous forms. However,
this website was written some people acting as science
journalists, and their reference to the "13 crystal forms"
is just a link to this website:
http://www.cmmp.ucl.ac.uk/people/finney/jlf.html
which includes a very pretty page saying that there are 11 crystal
forms:
http://www.cmmp.ucl.ac.uk/people/finney/soi.html
So, it's possible that these journalists made a mistake
about the number of crystalline forms.
On the other hand, they really do seem to be right
about 5 amorphous phases of ice, since they cite an
journal article which announced a new amorphous phase:
J. L. Finney, D. T. Bowron, A. K. Soper, T. Loerting, E. Mayer,
and A. Hallbrucker
Structure of a New Dense Amorphous Ice
Phys. Rev. Lett. 89, 205503 (2002)
(Received 11 July 2002; published 29 October 2002)
The detailed structure of a new dense amorphous ice, VHDA [very high
density amorphous ice], is determined by isotope substitution neutron
diffraction. Its structure is characterized by a doubled occupancy
of the stabilizing interstitial location that was found in high density
amorphous ice, HDA. As would be expected for a thermally activated
unlocking of the stabilizing "interstitial," the transition from VHDA
to LDA (low-density amorphous ice) is very sharp. Although its higher
density makes VHDA a better candidate than HDA for a physical
manifestation of the second putative liquid phase of water, as for
the HDA case, the VHDA to LDA transition also appears to be kinetically
controlled.
... and the text of this article mentions that it is the
fifth. Presumably we should add LDA, HDA and VHDA to the
ones you list above, IA and IIA, to get a total of five.
Also, since the latest phase was only discovered this year,
I wouldn't be surprised to see more phases being discovered
in the future. Water is truly versatile substance! I'm
reading a book about the physics of ice now... maybe I'll
talk about it in This Week's Finds sometime.
I have *no* idea what they mean by the "second putative liquid
phase of water" - do some people predict a new high-pressure,
high-temperature *liquid* phase of water?
Thanks for finding that website.
John Baez
In article <939044f.02112...@posting.google.com>,
Squark <fii...@yahoo.com> wrote:
>Eric Gisse <kseggR...@uas.alaska.edu> wrote in message
>news:<q04ttuo8ls186pjan...@4ax.com>...
>> Could it be that when the ice was formed, that many tiny bubbles of
>> nitrogen were trapped in it, and the result was simply something
>> opaque? Cracks or other deformations in ice are not clear.
>I don't know. I do know one guy who seems to be a solid state expert
>who claims this ice _is_ a different crystalline form. I haven't
>figured out what makes him so sure yet, though.
Water vapor condensing on surfaces the temperature of liquid
air forms amorphous ice. That's not quite your setup here, but
maybe...?
Ken Muldrew
ba...@galaxy.ucr.edu (John Baez) wrote:
>Squark <fii...@yahoo.com> wrote:
[snip discussion of water drops in liquid nitrogen solidifying in a
state that is not ice 1h]
>>I don't know. I do know one guy who seems to be a solid state expert
>>who claims this ice _is_ a different crystalline form. I haven't
>>figured out what makes him so sure yet, though.
>Water vapor condensing on surfaces the temperature of liquid
>air forms amorphous ice. That's not quite your setup here, but
>maybe...?
Not a chance. In order to get liquid water to vitrify the sample has
to be microscopic and the cooling rate has to be extremely fast
(liquid nitrogen won't be anywhere near sufficient). Of course if you
add some stuff to the water, say about 7 or 8M propylene glycol, then
you will get a glass (but it will be clear, not opaque, in
contradiction with the original observation).
Ken Muldrew
kmul...@ucalgary.ca
John Devers
friend of mine who came up with this question out of the blue after
telling him ice 13 sinks in water. (I hope it was ice 13) :-)
>From DR.V
Are there any heavy water forms of ice and how many?
e.g. The deuterium, tritium type.
John Baez
John Devers <johnd...@froggy.com.au> wrote:
>Hi there again jb. I was just showing this thread to a doctor (Md.)
>friend of mine who came up with this question out of the blue after
>telling him ice 13 sinks in water. (I hope it was ice 13) :-)
Ice 13 *would* sink in water, except that it's only stable under
pressures so high that this water would be compressed into... ice 13!
Moral: take everything science journalists say with a grain of salt.
Think carefully about what they say and see if it actually makes sense.
>From DR.V:
>>Are there any heavy water forms of ice and how many?
>>e.g. The deuterium, tritium type.
Sure, there are lots. You can replace either or both hydrogen
atoms in your H2O with a different isotope: deuterium or tritium.
This gives 6 isotopic forms of water: H20, HDO, HTO, D20, DTO and T2O.
D2O ice cubes sink in water, and you can see them doing it here:
http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA2/MAIN/ICECUBE/CD2R1.HTM
I don't know if HDO or HTO ice cubes sink in water, but clearly
DTO and T2O do, since they are even denser than D2O.
On the web you can find a place where somebody asks if HDO
ice cubes sink in water, and receives some silly answers.
Does anyone here actually know?
Tritium is radioactive with a half-life of about 12.4 years, so
water on earth is mainly H2O, HDO and D2O. About 1.5% of the
hydrogen on our planet is deuterium, so about 1.5% of the water is
HDO, while about 1.5% of 1.5% is D2O - or in other words, about .02%
To make matters even more complicated, there are three different
stable isotopes of oxygen. About 99.759% of the oxygen on Earth
is good old oxygen-16, but about .037% is oxygen-18 and about
.037% is oxygen-17.
So, instead of just 3 stable isotopic forms of water (H2O, HDO, and
D20), there are really 9 if we count the various isotopes of oxygen.
Each one has its own slightly different chemical properties.
Many microorganisms can survive in a medium where all the water
is D2O, although they grow more slowly than in H20. However,
mammals get sick if too much of their body water is D2O. In
fact, toxic effects occur when about 20% of the water in their
body is D20. This might serve as the basis of an interesting
murder mystery. It's also a nice illustration of how evolution
tends to optimize life relative to the underlying physics,
making ever smaller changes in the laws of physics sufficient
to cause problems.
I wonder if we could live drinking only HDO. Since it has
properties between those of H20 and D20, we might have a better
chance.
Of course this is a fairly useless thing to wonder about...
but people *do* like to use microorganisms to make complicated
chemicals in which all the hydrogen has been replace by
deuterium!
Refs:
Katz JJ (1960) The biology of heavy water. Scientific American,
July 1960, pp 106-115.
Katz JJ (1965) Chemical and biological studies with deuterium.
39th Annual Priestly Lecture, Pennsylvania State University. pp 1-110.
Thomson JF (1963) _Biological Effects of Deuterium_, Pergamon Press,
Macmillan. New York. 133 pp.
D.J. Kushner, Alison Baker and T.G. Dunstall,
BIOTECHNOLOGICAL POTENTIAL OF HEAVY WATER AND DEUTERATED COMPOUNDS,
http://www.isb.vt.edu/brarg/brasym96/kushner96.htm
Squark
> Are there any heavy water forms of ice and how many?
>
> e.g. The deuterium, tritium type.
The chemical properties of deuterium / tritium are identical to
those usual hyrdrogen, therefore one probabely gets precisely the
same sorts of ice. Of course, the atoms have a different mass now,
but I don't see how that can alter things much. Naively one can
claim the net (electromagnetic) force on any atomic nuclei within
the crystalline lattice vanishes, and this would hold whatever the
mass of the nucleus is.
What might change is the phase diagram (the location of the phase
boundaries), as I would expect the nature of themral fluctuations
to depend on the nuclear masses to some extent (i.e., heavier
atoms "driggle" less at the same temperature). Even so, the
differences would probabely be relatively small.
J. J. Lodder
> To make matters even more complicated, there are three different
> stable isotopes of oxygen. About 99.759% of the oxygen on Earth
> is good old oxygen-16, but about .037% is oxygen-18 and about
> .037% is oxygen-17.
>
> So, instead of just 3 stable isotopic forms of water (H2O, HDO, and
> D20), there are really 9 if we count the various isotopes of oxygen.
> Each one has its own slightly different chemical properties.
And physical too, such as slower evaporation.
Measuring for example \delta O18
in Greenland ice cores or in fossil shells
is a way to determine paleoclimate.
Best,
Jan
Squark
> Ice 13 *would* sink in water, except that it's only stable under
> pressures so high that this water would be compressed into... ice 13!
Well, imagine I keep it packed in a very strong, thermally isolating
box. :-)
> On the web you can find a place where somebody asks if HDO
> ice cubes sink in water, and receives some silly answers.
> Does anyone here actually know?
I don't know, but I can try guess. It appears to me (as I wrote in
another post) as if the crystall lattice wouldn't be affected much by
the replacement of H by D*, and so a naive computation of
ice density * D's atomic mass / water density * H's atomic mass
should do. I don't have the numbers, though.
*In other words, the approximation m_nucleus >> m_electron is
supposedly a good one for this purpose.
David Madore
> In article <2978f9d5.02120...@posting.google.com>,
> John Devers <johnd...@froggy.com.au> wrote:
>>Hi there again jb. I was just showing this thread to a doctor (Md.)
>>friend of mine who came up with this question out of the blue after
>>telling him ice 13 sinks in water. (I hope it was ice 13) :-)
>
> Ice 13 *would* sink in water, except that it's only stable under
> pressures so high that this water would be compressed into... ice 13!
*Is* there such a thing as Ice 13, anyway? The table on <URL:
http://skua.gps.caltech.edu/hermann/ice.table1.html > lists 13 forms
of ice, but the numbering does not include an ice 13.
Any kind of ice except Ih and Ic has a density greater than that of
water at usual room conditions: therefore, any form of ice except Ih
and Ic would "sink in water". But in a more precise sense, the
boundary of the phase diagram <URL:
http://skua.gps.caltech.edu/hermann/ice.fig2.html > between ice and
liquid water are seen to have positive slope except for ice I, so we
might say that ice III, ice IV, ice VI and ice VII (and presumably ice
X also) can really be made to sink in liquid water (albeit at very
high pressures); ices VIII, on the other hand, cannot apparently be
put in contact with liquid water.
> Moral: take everything science journalists say with a grain of salt.
> Think carefully about what they say and see if it actually makes sense.
It seems to me that it does make sense, if, for example, ice III was
meant.
>>>Are there any heavy water forms of ice and how many?
>>>e.g. The deuterium, tritium type.
>
> Sure, there are lots. You can replace either or both hydrogen
> atoms in your H2O with a different isotope: deuterium or tritium.
> This gives 6 isotopic forms of water: H20, HDO, HTO, D20, DTO and T2O.
>
> D2O ice cubes sink in water, and you can see them doing it here:
>
> http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA2/MAIN/ICECUBE/CD2R1.HTM
>
> I don't know if HDO or HTO ice cubes sink in water, but clearly
> DTO and T2O do, since they are even denser than D2O.
Would I be naive in assuming that the density ratio of HDO to H2O ice
is extremely close to the molecular mass ratio of the two? This would
give a density of 0.98, so HDO ice should still float in liquid H2O.
> Many microorganisms can survive in a medium where all the water
> is D2O, although they grow more slowly than in H20. However,
> mammals get sick if too much of their body water is D2O. In
> fact, toxic effects occur when about 20% of the water in their
> body is D20. This might serve as the basis of an interesting
> murder mystery.
I'm surprised to learn this - I thought we might survive much greater
changes. What are the symptoms of D2O poisoning like, and what,
precisely, are they due to?
--
David A. Madore
(david....@ens.fr,
http://www.eleves.ens.fr:8080/home/madore/ )
John Devers
> Sure, there are lots. You can replace either or both hydrogen
> atoms in your H2O with a different isotope: deuterium or tritium.
> This gives 6 isotopic forms of water: H20, HDO, HTO, D20, DTO and T2O.
Are these types included in the list of 13?
Can all the forms of ice available and discovered so far include the
extra neutron or does it inhibit some formations?
Does heavy water inhibit or enhance the transiton to ice?
Does it decrease or increase any time taken for phase transitions?
Do all these ices have the hexatic phase between solid and liquid?
John Baez
David Madore <david....@ens.fr> wrote:
>John Baez in litteris <atdt8g$vl$1...@glue.ucr.edu> scripsit:
>> In article <2978f9d5.02120...@posting.google.com>,
>> John Devers <johnd...@froggy.com.au> wrote:
>>>Hi there again jb. I was just showing this thread to a doctor (Md.)
>>>friend of mine who came up with this question out of the blue after
>>>telling him ice 13 sinks in water. (I hope it was ice 13) :-)
>> Ice 13 *would* sink in water, except that it's only stable under
>> pressures so high that this water would be compressed into... ice 13!
>*Is* there such a thing as Ice 13, anyway? The table on <URL:
>http://skua.gps.caltech.edu/hermann/ice.table1.html > lists 13 forms
>of ice, but the numbering does not include an ice 13.
Yeah. We had a big discussion of *that* already; see
http://www.google.com/groups?selm=asefbe%24hua%241%40glue.ucr.edu&output=gplain
for a post in which I corrected Devers' apparent misimpression
that 13 crystalline forms of ice are listed in this chart.
So, in the post you cite I decided to stop picking on Devers
and assume that *whatever* the hell he was talking about,
it was one of these high-density forms of ice that's stable
only at high pressures. Remember, he helped start
this conversation by mentioning a news report
http://www.aip.org/enews/physnews/2002/split/612-3.html
which discusses a new form of ice that "would sink in water,
not float like regular ice."
(This new form of ice is called "VHDA Ice", not "Ice XIII".
It's apparently the fifth known amorphous form of ice,
"very high density amorphous" ice.)
I'm sorry to create further confusion.
>Would I be naive in assuming that the density ratio of HDO to H2O ice
>is extremely close to the molecular mass ratio of the two?
It's probably quite close, though certainly not *exactly* the same.
For example, a deuterium atom will have a slightly smaller *size*
than a normal hydrogen atom, as well as having about twice
the usual mass. So, HDO ice might a little bit more dense
than one would naively guess.
Remember, the Bohr radius of a hydrogen atom is inversely
proportional to the reduced mass
mM/(m + M)
where m is the electron mass and M is the nucleus mass.
As M -> infinity this reduced mass increases and approaches m.
So, the hydrogen atom gets a bit *smaller* when we make the
nucleus more massive. But the shrinkage is small when we go
from normal hydrogen to deuterium: it will be on the order
of one part in 2000, I guess. (I'm too lazy to do the arithmetic.)
Of course this analysis is for atomic hydrogen; actual ice
is a lot more complicated! But I'd be willing to bet a doughnut
that the effect will still point the same way, and be of
roughly the same magnitude.
>This would
>give a density of 0.98, so HDO ice should still float in liquid H2O.
Okay, I'll believe that answer until I hear otherwise. This
density is almost 1, but the difference is 2%, a lot more than
one part in 2000.... so any subtle extra "shrinkage" effect is
probably not enough to make HDO sink.
But someone should do the experiment!
>> Many microorganisms can survive in a medium where all the water
>> is D2O, although they grow more slowly than in H20. However,
>> mammals get sick if too much of their body water is D2O. In
>> fact, toxic effects occur when about 20% of the water in their
>> body is D20. This might serve as the basis of an interesting
>> murder mystery.
>I'm surprised to learn this - I thought we might survive much greater
>changes. What are the symptoms of D2O poisoning like, and what,
>precisely, are they due to?
Apparently the victim is overcome with a feeling of heaviness
and eventually explodes in a spontaneous thermonuclear reaction.
Just kidding. I don't actually know: I was only able to get
ahold of one of these references in my previous post, and it
didn't say. Now you've got me quite curious!
I really like the idea of a murder mystery where someone
dies of unknown causes and then his wife notices that his
corpse is mysteriously *10% heavier* than his usual weight,
even though he doesn't look fatter.
Btw, your article was missing the all-important "References"
line in the header which hooks it up to previous articles
on the "Ice" thread. I stuck some of those references in
this article of mine just now...
John Baez
John Devers <johnd...@froggy.com.au> wrote:
>ba...@galaxy.ucr.edu (John Baez) wrote in message
>news:<atdt8g$vl$1...@glue.ucr.edu>...
>> Sure, there are lots. You can replace either or both hydrogen
>> atoms in your H2O with a different isotope: deuterium or tritium.
>> This gives 6 isotopic forms of water: H20, HDO, HTO, D20, DTO and T2O.
>Are these types included in the list of 13?
Gosh, no!!! We're talking about isotopes now, not diffferent
crystalline and amorphous forms of ice! Take 13 kinds of ice,
multiply them by the above 6 kinds of water, multiply that by 3
different isotopes of *oxygen* you can have in your water...
now we've got 234 kinds of ice to study. But I'd be *really*
surprised if anyone were insane enough to have studied them all.
>Can all the forms of ice available and discovered so far include the
>extra neutron or does it inhibit some formations?
I'm not sure, but I would gladly run around naked at UCR singing
odes in praise of the Bogdanoff brothers if it turned out to be
*impossible* to make one of the currently known forms of ice
with any of the various isotopic forms of water.
The chemical differences between H20, HDO, HTO, D20, DTO and T2O
are simply too minor to cause such a thing as that!
>Does heavy water inhibit or enhance the transition to ice?
Heavier atoms are harder to shake around... so expect
a higher melting point for the heavier forms of water.
Higher boiling point, too. You can look this stuff up,
at least for D20.
>Does it decrease or increase any time taken for phase transitions?
"Time for phase transition" is too vague for me to understand;
I could try to make up a meaning for this phrase, but I'd rather not.
>Do all these ices have the hexatic phase between solid and liquid?
Huh? Hexatic phases arise in thin liquid-crystal films, but
I haven't heard of *any* hexatic phase of water. Are you
claiming such a thing exists?
Uncle Al
>
> johnd...@froggy.com.au (John Devers) wrote in message news:<2978f9d5.02120...@posting.google.com>...
> > Are there any heavy water forms of ice and how many?
> >
> > e.g. The deuterium, tritium type.
>
> The chemical properties of deuterium / tritium are identical to
> those usual hyrdrogen, therefore one probabely gets precisely the
> same sorts of ice. Of course, the atoms have a different mass now,
> but I don't see how that can alter things much. Naively one can
> claim the net (electromagnetic) force on any atomic nuclei within
> the crystalline lattice vanishes, and this would hold whatever the
> mass of the nucleus is.
You are intensely incorrect. Isotope effects, deuterium vs. protium,
are very large. Physical properties of D2O vs. H2O are significantly
disparate as hydrogen bond strength is significantly impacted. Look
at H-M vs. D-M bonding in the IR, M bing any element. Normalize for
the mass difference in the oscillator, then look for residual
frequency shift from differing bond parameters. It's not subtle.
T2O would be vastly disaparate if its decay heat didn't spontaneously
boil it. Compare the energy output of a gram of radium vs. a gram of
tritium, and remember to correct for moles/gram as well as half-life
differences.
C-13 diamond is about 3% stronger than common diamond from isotope
effect. That 3% difference equals the total tensile strength of the
best spring steel.
Tim S
> johnd...@froggy.com.au (John Devers) wrote in message
> news:<2978f9d5.02120...@posting.google.com>...
>> Are there any heavy water forms of ice and how many?
>>
>> e.g. The deuterium, tritium type.
>
> The chemical properties of deuterium / tritium are identical to
> those usual hyrdrogen, therefore one probabely gets precisely the
> same sorts of ice.
I don't think this is true. IIRC, the bond acts like a harmonic oscillator
whose frequency and therefore energy levels depend on the masses of the
nuclei. For most pairs of isotopes this doesn't make a significant
difference, but for protium/deuterium/tritium it significantly affects bond
energies.
I don't know if this affects the forms of ice, but I think it makes heavy
water poisonous.
Tim
Pieter Kuiper
> I'm not sure, but I would gladly run around naked at UCR singing
> odes in praise of the Bogdanoff brothers if it turned out to be
> *impossible* to make one of the currently known forms of ice
> with any of the various isotopic forms of water.
> The chemical differences between H20, HDO, HTO, D20, DTO and T2O
> are simply too minor to cause such a thing as that!
I would not bet on that.
The density maxima near 4.0∞C (H2O), 11.2∞C (D2O), and 13.4∞C (T2O) show
a strong isotope effect. <http://www.phys.ttu.edu/~dujcb/ECCC5/>
Maybe the Bogdanoff brothers should do a literature search on isotope
effects in the phase diagram of ice.
John Devers
> now we've got 234 kinds of ice to study. But I'd be *really*
> surprised if anyone were insane enough to have studied them all.
>
In an SSSF thread here, JF mentions H30+, does this figure of 234 include these?
http://www2b.abc.net.au/science/k2/stn/posts/topic279564.shtm
> Huh? Hexatic phases arise in thin liquid-crystal films, but
> I haven't heard of *any* hexatic phase of water. Are you
> claiming such a thing exists?
It's a phase between water and ice, unless I have misread this article?
Hexatic matter
John Devers
> for a post in which I corrected Devers' apparent misimpression
> that 13 crystalline forms of ice are listed in this chart.
>
> So, in the post you cite I decided to stop picking on Devers
> and assume that *whatever* the hell he was talking about,
> it was one of these high-density forms of ice that's stable
> only at high pressures. Remember, he helped start
> this conversation by mentioning a news report
>
Yep the lone moderator is being vey generous with the amature Aussie
physics readers this Xmas, sorry for any confusion, I'll try to call
it ice 5 from now on:-)
Calvin Ritchie
commented:
>Just kidding. I don't actually know: I was only >able to get ahold of one
of these references in >my previous post, and it didn't say. Now you've
>got me quite curious!
As you and others have already noted, the effects of substituting D for
H in a *static* molecule are expected to be quite small. However, what
no-one so far has noted is that the physical and chemical properties of
materials are often strongly dependent on the *dynamics* of the molecules.
That's where stat thermo comes in, and the effects can sometimes be quite
large.
For example, the ionization constants of acids in water and D2O often
differ by factors of greater than 2, and sometimes by a factor of nearly
ten. Also, the effect of substitution of a deuterium for a hydrogen on the
rates of reactions involving transfer of the isotope are usually on the
order of a factor of 6 (with transfer of hydrogen being faster than that of
deuterium) and, in some special cases, up to factors of 20 or more.
It is well established that the major contributor to these effects is
the differences in zero-point vibrational energies of the isotopes in
molecules. In this newsgroup, It's probably unnecessary to detail that, so
I'll just point out that the difference in zero-point energy for the O-H vs
O-D stretching in water is roughly 1.5 kcal/mole.
In a chemical system as complex as the human body, effects of 2-10 on
rates and/or equilibria of the various biochemical processes can be
disastrous.
For anyone wanting more detail, the chemical literature is loaded with
papers on deuterium (and other) isotope effects. Two references that I just
happen to have at hand are:
C. D. Ritchie, "Physical Organic Chemistry", 2nd Ed., M. Dekker, Inc.,
1990, Chapters 8 and 9;
J. F. Coetzee and C. D. Ritchie, Editors, "Solute-Solvent
Interactions", Vol. 1, M. Dekker, Inc. 1969, Chapters 6 (by E. M. Arnett)
and 7 (by Laughton and Robertson).
Arnett's chapter in the last reference has extensive tables of physical
data on water and D2O and on thermodynamics of things like solubilities in
the two liquids.
Just one further comment: It's a little hard to get data for pure
liquid HDO. The exchange of H for D is normally quite rapid and one gets an
equilibrium, nearly statistical, mixture of H2O, HDO, and D2O.
Submitted: Morning 17 Dec. 2002.
Don Ritchie
DonRit...@csWebmail.com
Ralph Hartley
> David Madore <david....@ens.fr> wrote:
>>John Baez in litteris <atdt8g$vl$1...@glue.ucr.edu> scripsit:
>>>Many microorganisms can survive in a medium where all the water
>>>is D2O, although they grow more slowly than in H20. However,
>>>mammals get sick if too much of their body water is D2O. In
>>>fact, toxic effects occur when about 20% of the water in their
>>>body is D20. This might serve as the basis of an interesting
>>>murder mystery.
>
>>I'm surprised to learn this - I thought we might survive much greater
>>changes. What are the symptoms of D2O poisoning like, and what,
>>precisely, are they due to?
...
> I don't actually know
This was apparently discussed on sci.phisics by people who's names you will
find familiar, see http://yarchive.net/med/heavy_water.html
Apparently, it interferes with microtubule function somehow, so the effects
would be similar to some chemotherapy agents, e.g. Vincristine.
> I really like the idea of a murder mystery where someone
> dies of unknown causes and then his wife notices that his
> corpse is mysteriously *10% heavier* than his usual weight,
> even though he doesn't look fatter.
They covered that too. It was the sinking ice cubes that gave it away.
Heavy water might be one of the few poisons that is *more* expensive than
chemo drugs.
Ralph Hartley
Ken Muldrew
>David Madore <david....@ens.fr> wrote:
>>> Many microorganisms can survive in a medium where all the water
>>> is D2O, although they grow more slowly than in H20. However,
>>> mammals get sick if too much of their body water is D2O. In
>>> fact, toxic effects occur when about 20% of the water in their
>>> body is D20. This might serve as the basis of an interesting
>>> murder mystery.
>
>>I'm surprised to learn this - I thought we might survive much greater
>>changes. What are the symptoms of D2O poisoning like, and what,
>>precisely, are they due to?
>
>Apparently the victim is overcome with a feeling of heaviness
>and eventually explodes in a spontaneous thermonuclear reaction.
I believe that the problem that eukaryotes have in D2O is that
microtubule polymerization doesn't happen due to a change in hydrogen
bonding (that's pretty vague because I can't remember where I read it,
but if it comes to me I'll look it up again). So maybe you were
thinking that they died from a spontaneous loss of quantum coherence.
;-)
But seriously, if microtubules couldn't polymerize properly then there
would be no mitosis and cell trafficking would be inhibited (the
movement of stuff from one part of the cell to another using little
nano-machines that ride on utubules). I don't know if this happens in
HDO as well but since D2O goes to HDO in normal water, you would need
to feed someone a lot of D2O to poison them.
>Just kidding. I don't actually know: I was only able to get
>ahold of one of these references in my previous post, and it
>didn't say. Now you've got me quite curious!
I think the relevant experiments have been done in mice. A quick
glance at pubmed shows that 50% D2O alters hematopoiesis significantly
but not much else shows up.
>I really like the idea of a murder mystery where someone
>dies of unknown causes and then his wife notices that his
>corpse is mysteriously *10% heavier* than his usual weight,
>even though he doesn't look fatter.
The above-mentioned hematopoiesis paper claims that there is
dehydration due to a decreased fluid intake so the corpse might be
*lighter* than normal. Probably the giveaway would be the huge stack
of empty jugs out beside the trash.
Ken Muldrew
kmul...@ucalgary.ca
Squark
johnd...@froggy.com.au (John Devers) wrote in message news:<2978f9d5.02121...@posting.google.com>...
> > I haven't heard of *any* hexatic phase of water. Are you
> > claiming such a thing exists?
>
> It's a phase between water and ice, unless I have misread this article?
>
> Hexatic matter
>
> http://focus.aps.org/v10/st5.html
Neither water nor ice is mentioned once in this article. Liquid-crystal
films _are_ on the hand, as well as "spherical carbon tetrachloride"
(also in thin film).
Squark
> ...Isotope effects, deuterium vs. protium,
> are very large. Physical properties of D2O vs. H2O are significantly
> disparate as hydrogen bond strength is significantly impacted.
Why is the hydrogen bond affected the most?
> Look at H-M vs. D-M bonding in the IR, M bing any element. Normalize for
> the mass difference in the oscillator, then look for residual
> frequency shift from differing bond parameters. It's not subtle.
It's fairly reasonable things would look different, but in the case of the
crystalline structure, the dependance on those difference should be rather
week. Very roughly, we would have different sort of oscillations around
the equilibrium, but about the same equilibrium.
Again, it probabely makes sense to speak of the infinite nucleus mass
limit, and if does it's no surprise different masses lead to similar
qualitive behavior - what cannot happen if we get divergence at the
infinite mass limit.
> T2O would be vastly disaparate if its decay heat didn't spontaneously
> boil it.
Okay, radioactive decay effects do add further subtleties. However, it's
not clear how can it lead to significant alteration of the crystalline
structure.
> C-13 diamond is about 3% stronger than common diamond from isotope
> effect. That 3% difference equals the total tensile strength of the
> best spring steel.
Alright, but does it have a different lattice?
Squark
> on 16/12/02 4:23 am, Squark at fii...@yahoo.com wrote:
> > The chemical properties of deuterium / tritium are identical to
> > those usual hyrdrogen, therefore one probabely gets precisely the
> > same sorts of ice.
>
> I don't think this is true. IIRC, the bond acts like a harmonic oscillator
> whose frequency and therefore energy levels depend on the masses of the
> nuclei. For most pairs of isotopes this doesn't make a significant
> difference, but for protium/deuterium/tritium it significantly affects bond
> energies.
In other words, the groundstate energy makes the difference. This is true,
and this is a purely quantum effect (not as if anything here can be modelled
classically, it's just so "ideologically quantum" :-)).
This indeed weakens my arguement, though, as far as I understand, in practice
the difference is still not large enough to significantly alter the geometry
of those crystal lattices. Or is it?
> I don't know if this affects the forms of ice, but I think it makes heavy
> water poisonous.
Hmm, why interesting. How, exactly?
Squark
"why interesting" in my reply to Tim should be read "very interesting".
You must forgive me, though, I'm writing this at 11:30 PM :-)
Squark
> John Baez wrote:
> > I really like the idea of a murder mystery where someone
> > dies of unknown causes and then his wife notices that his
> > corpse is mysteriously *10% heavier* than his usual weight,
> > even though he doesn't look fatter.
>
> They covered that too. It was the sinking ice cubes that gave it away.
Sinking ice cubes? Didn't someone on this newsgroup computed heavy ice
to float?
J. J. Lodder
> John Devers <johnd...@froggy.com.au> wrote:
>
> >ba...@galaxy.ucr.edu (John Baez) wrote in message
> >news:<atdt8g$vl$1...@glue.ucr.edu>...
>
> >> Sure, there are lots. You can replace either or both hydrogen
> >> atoms in your H2O with a different isotope: deuterium or tritium.
> >> This gives 6 isotopic forms of water: H20, HDO, HTO, D20, DTO and T2O.
>
> >Are these types included in the list of 13?
>
> Gosh, no!!! We're talking about isotopes now, not diffferent
> crystalline and amorphous forms of ice! Take 13 kinds of ice,
> multiply them by the above 6 kinds of water, multiply that by 3
> different isotopes of *oxygen* you can have in your water...
> now we've got 234 kinds of ice to study. But I'd be *really*
> surprised if anyone were insane enough to have studied them all.
It may surprise you,
but that is just the kind of thing
some experimentalists love to do.
(Just so that they can chalenge some poor sod of a theoretician
to predict the results of course :-)
In the case of ices however it is not insanity which prevents them,
but very practical problems.
Preparing isotopically pure ices (say DTO17)
would be prohibitively expensive.
Merely producing isotopicically enriched chemical compounds,
with excess C13 or O17 is already expensive.
It is routine done however, for C12 and O16 (unlike protons)
do not have a nuclear spin.
With isotopically enriched compounds you can do NMR,
and hence structural analysis of molecules.
Best,
Jan
Kevin A. Scaldeferri
In article <939044f.02121...@posting.google.com>,
Squark <fii...@yahoo.com> wrote:
>Ralph Hartley <har...@aic.nrl.navy.mil> wrote in message news:<atntvg$g44$1...@ra.nrl.navy.mil>...
>> John Baez wrote:
>> > I really like the idea of a murder mystery where someone
>> > dies of unknown causes and then his wife notices that his
>> > corpse is mysteriously *10% heavier* than his usual weight,
>> > even though he doesn't look fatter.
>>
>> They covered that too. It was the sinking ice cubes that gave it away.
>
>Sinking ice cubes? Didn't someone on this newsgroup computed heavy ice
>to float?
I'm not sure. It may depend on exactly what you are asking: does
heavy ice float in heavy water vs. does heavy ice float in normal
water?
In the first case, one wouldn't naively expect the isotopic content to
affect the packing density much, either in liquid or solid form. A
10% effect would be quite surprising (at least to me). So, I expect
that heavy ice floats in heavy water. (For any type of "heavy").
Next, does heavy ice float or sink in regular water. Well, we know
that ice is about 10% less dense than water. D2O is about 11% heavier
than H2O, so it probably sinks, although you'd want to check the
numbers more closely. T2O almost certainly sinks, as does TDO. HDO
probably floats.
Still another question along the lines is what happens when you have a
mixture of types of water and you cool it. Does the resulting ice
float or sink? This is complicated by the fact that there should be
some affect on the freezing temp. from the isotope, so the different
species don't all freeze out at the same time.
--
======================================================================
Kevin Scaldeferri Calif. Institute of Technology
The INTJ's Prayer:
Lord keep me open to others' ideas, WRONG though they may be.
John Baez
John Baez <ba...@galaxy.ucr.edu> wrote:
>In article <1PkVnJ9jBwYswZ1$@clipper.ens.fr>,
>David Madore <david....@ens.fr> wrote:
>>Would I be naive in assuming that the density ratio of HDO to H2O ice
>>is extremely close to the molecular mass ratio of the two?
>>This gives a density of 0.98, so HDO ice should still float in liquid H2O.
>It's probably quite close, though certainly not *exactly* the same.
>For example, a deuterium atom will have a slightly smaller *size*
>than a normal hydrogen atom, as well as having about twice
>the usual mass. So, HDO ice might a little bit more dense
>than one would naively guess.
>
>Remember, the Bohr radius of a hydrogen atom is inversely
>proportional to the reduced mass
>
>mM/(m + M)
>
>where m is the electron mass and M is the nucleus mass.
>As M -> infinity this reduced mass increases and approaches m.
>So, the hydrogen atom gets a bit *smaller* when we make the
>nucleus more massive. But the shrinkage is small when we go
>from normal hydrogen to deuterium: it will be on the order
>of one part in 2000, I guess. (I'm too lazy to do the arithmetic.)
>
>Of course this analysis is for atomic hydrogen; actual ice
>is a lot more complicated! But I'd be willing to bet a doughnut
>that the effect will still point the same way, and be of
>roughly the same magnitude.
As already pointed out by others, we can get much bigger
isotope effects in situations where hydrogen atoms are *moving*.
For example, I bet a lot of specific heat of water is due to
vibrational and rotational modes where the hydrogen "Mickey mouse
ears" wiggle or spin around the oxygen atom. If one of these ears
becomes twice as heavy as usual, there could be big consequences.
This applies to liquid or gaseous water... but what about ice? Even
here vibrational modes can be important... so my previous guess
was too naive, and I take back that offer of a doughnut, as well
as the offer to run around naked singing praises of the Bogdanoffs
if some form of ice cannot be made with certain isotopic forms
of hydrogen. (Sorry, Igor and Grichka!)
But now I'm getting curious:
Can anyone look up the density of ordinary D20 ice, divide
it by the density of ordinary H20 ice at the same temperature
and pressure, and compare *that* ratio to the ratio of their
molecular weights?
I'd be able to do this in an instant if I were back in my office, but
right now I'm having trouble finding this information. It would
serve as a nice test of David Madore's guess. I *would have*
predicted these ratio would agree to within about one part in
a thousand... but *now* I'm mentally prepared for much bigger
deviations!
John Baez
Kevin A. Scaldeferri <ke...@its.caltech.edu> wrote:
>In article <939044f.02121...@posting.google.com>,
>Squark <fii...@yahoo.com> wrote:
>>Sinking ice cubes? Didn't someone on this newsgroup computed heavy ice
>>to float?
>I'm not sure. It may depend on exactly what you are asking: does
>heavy ice float in heavy water vs. does heavy ice float in normal
>water?
As I already said, D2O ice cubes sink in liquid H2O water, and you
can see them doing it here:
http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA2/MAIN/ICECUBE/CD2R1.HTM
I'm pretty sure D2O ice cubes float in liquid D2O.
The fun question due to David Madore was whether HDO ice cubes
float or sink in liquid H2O. He guessed it floats... just barely.
I originally agreed with his calculation; later I began worrying
that vibrational modes of the hydrogen atoms make things more
complicated. But now I just read an article by Don Ritchie
which suggests to me that this question may be rendered somewhat
silly by the fact that HDO quickly turns into a mixture of H2O, D2O and HDO.
This is obviously true in the liquid state - at least now that
I think about it, that is. But in fact, even in ice, it's easy
for hydrogens to switch from one oxygen to another! So, there
may really be no difference between "HDO ice" and "a mixture of
H2O, D2O and HDO ice".
In fact, the crystal structure of ordinary ice (ice Ih) has an interesting
ambiguity about it. Take a look at the left-hand picture here:
http://skua.gps.caltech.edu/hermann/ice.fig1.html
You'll see balls representing oxygen atoms connected by imaginary
rods on which hydrogen nuclei lie. The hydrogen nuclei are not
shown, but they lie on these rods in an asymmetric way: closer
to one oxygen than the other.
Each oxygen has 4 rods coming out of it in a tetrahedral pattern.
In the state of least energy, hydrogen nuclei will lie NEAR the
oxygen on 2 of these rods, and FAR from the oxygen on the other 2.
But there are lots of different ways for this to occur - lots of
different patterns - and in reality, the hydrogen nuclei move
around between these different patterns!
So, ice Ih doesn't have a truly unique structure: it has lots,
and it keeps hopping between these structures. In fact, Linus Pauling
used this to calculate the entropy of ice, which is mainly due to
this effect! More recently, mathematicians have had a lot of fun
studying a simplified 2d model of this phenomenon, called "square ice".
It's exactly soluble... and I *don't* mean soluble in water! :-)
This model is related to the Yang-Baxter equations.
Anyway, this interesting feature of ice means that "HDO ice" isn't
really different from "a mixture of H2O, D2O and HDO ice". At
least, not for long.
Of course, we could still try to measure its density and see if
it floats on ordinary water!
Squark
ke...@its.caltech.edu (Kevin A. Scaldeferri) wrote in message news:<au2lnb$2km$1...@clyde.its.caltech.edu>...
> Still another question along the lines is what happens when you have a
> mixture of types of water and you cool it. Does the resulting ice
> float or sink? This is complicated by the fact that there should be
> some affect on the freezing temp. from the isotope, so the different
> species don't all freeze out at the same time.
This relates to the more general question of what happens to the phase
diagram of a mixture. I think usually the number of phases is still the
same, i.e., the crystallization of the whole business happens at a
certain particular temperature.
Otherwise, it would require the separation of various components of the
mixture into some kind of bubbles. How can that happen? Well, maybe it
can if the attraction between same molecules somehow becomes much
greater than the attraction between different ones.
Or maybe such bubbles can spontaneously form over a long time because
of "thermodynamical" reasons.
What _does_ happen?
John Devers
(Squark) wrote in message
> Neither water nor ice is mentioned once in this article. Liquid-crystal
> films _are_ on the hand, as well as "spherical carbon tetrachloride"
> (also in thin film).
>
> Best regards,
> Squark
One day I may learn to read more carefully. Thankyou for pointing that
out:-)
I take it then that water does not go through the hexatic phase?
I know I have read of transition phases in between water and ice in
Nature magazine, though I don't have a ref. handy.
What are the phases between water and ice?
Uncle Al
John Baez wrote:
>
> In article <atmblm$3u2$1...@glue.ucr.edu>,
> John Baez <ba...@galaxy.ucr.edu> wrote:
>
> >In article <1PkVnJ9jBwYswZ1$@clipper.ens.fr>,
> >David Madore <david....@ens.fr> wrote:
> Can anyone look up the density of ordinary D20 ice, divide
> it by the density of ordinary H20 ice at the same temperature
> and pressure, and compare *that* ratio to the ratio of their
> molecular weights?
>
> I'd be able to do this in an instant if I were back in my office, but
> right now I'm having trouble finding this information. It would
> serve as a nice test of David Madore's guess. I *would have*
> predicted these ratio would agree to within about one part in
> a thousand... but *now* I'm mentally prepared for much bigger
> deviations!
http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA2/MAIN/ICECUBE/CD2R1.HTM
http://www.sbu.ac.uk/water/anmlies.html
http://www.sbu.ac.uk/water/explan.html#Isotope
I can't find the density of deuterium oxide ice anywhere - CRC, Merck
Index, Web - which is remarkable.
J. J. Lodder
J. J. Lodder <nos...@de-ster.demon.nl> wrote:
[Addendum]
Undercooling, followed by rapid partial freezing
upon introduction of a seed. is a standard laboratory trick
to determine melting points accurately.
The heat of crystalization warms the sample
precisely to its melting point.
Otherwise systematic errors due to undercooling the liquid
or overheating the crystal may spoil the measurement.
Best,
Jan
> And Vonnegut goes on to fall into a trap that is as old as SF:
> The belief that undercooled water will freeze solid
> with the introduction of a seed.
> Jules Verne already has an ocean freeze solid instantaneously
> and I have been told that Brian Aldiss has the same mistake
> as a dramatic device somewhere in his Helliconia series.
> There must be others.
>
> Actually, the phase transition liberates far more heat
> than can be stored by undercooling.
> With the introduction of the seed only a small fraction
> of the water will freeze, warming the rest to the melting point.
>
> Eating Ice-nine would not kill by freezing you solid:
> it would kill by warming you to its melting point.
David Madore
scripsit:
>> And Vonnegut goes on to fall into a trap that is as old as SF:
>> The belief that undercooled water will freeze solid
>> with the introduction of a seed.
>>
>> than can be stored by undercooling.
>> With the introduction of the seed only a small fraction
>> of the water will freeze, warming the rest to the melting point.
How about superheating a liquid? Is it likewise true that you can
only get a small amount to evaporate because the latent heat that is
absorbed in the evaporation process of this small amount is sufficient
to cool the liquid to its boiling point?
There is this famous "kitchen physics" experiment (kids, don't try
this at home!) that consists of putting a bowl of water in the
microwave for some time, causing the water to remain liquid, but if
you move it ever so slightly it will "explose" at you very suddenly.
The usual explanation is that this is due to the water becoming
superheated quite beyond its 373K boiling point (because there is no
seed for bubbles to start a boiling process), whereafter a slight
perturbation will cause it to revert to thermodynamical equilibrium.
I have never tried this, but some witnesses tell me they were left
with no water left in the bowl: but this seems indeed unlikely, from
what you point out, because the evaporation should absorb a large
amount of heat. Perhaps it was simply that the remaining liquid water
(right at 373K) was projected away from the container (making the
experiment quite dangerous).
Any comments on this experiment? Perhaps the "usual" explanation is
just an urban legend (I tend to be wary of such, because I have seen
so many "well-known" facts rectified on this very newsgroup).
J. J. Lodder
David Madore <david....@ens.fr> wrote:
> J. J. Lodder in litteris <1fo6psu.1g5...@de-ster.xs4all.nl>
> scripsit:
> >> And Vonnegut goes on to fall into a trap that is as old as SF:
> >> The belief that undercooled water will freeze solid
> >> with the introduction of a seed.
> >>
> >> Actually, the phase transition liberates far more heat
> >> than can be stored by undercooling.
> >> With the introduction of the seed only a small fraction
> >> of the water will freeze, warming the rest to the melting point.
>
> How about superheating a liquid? Is it likewise true that you can
> only get a small amount to evaporate because the latent heat that is
> absorbed in the evaporation process of this small amount is sufficient
> to cool the liquid to its boiling point?
Yes, and even more so,
since heats of evaporation are usually greater than heats of melting.
> There is this famous "kitchen physics" experiment (kids, don't try
> this at home!) that consists of putting a bowl of water in the
> microwave for some time, causing the water to remain liquid, but if
> you move it ever so slightly it will "explose" at you very suddenly.
> The usual explanation is that this is due to the water becoming
> superheated quite beyond its 373K boiling point (because there is no
> seed for bubbles to start a boiling process), whereafter a slight
> perturbation will cause it to revert to thermodynamical equilibrium.
> I have never tried this, but some witnesses tell me they were left
> with no water left in the bowl: but this seems indeed unlikely, from
> what you point out, because the evaporation should absorb a large
> amount of heat. Perhaps it was simply that the remaining liquid water
> (right at 373K) was projected away from the container (making the
> experiment quite dangerous).
The explosive boil generates bubbles, which propel the liquid.
An even more dangerous form of this experiment
is to heat water in a test tube over a Bunsen burner.
You need a very clean container and though.
Making a cup of tea in the microwave is harmless.
> Any comments on this experiment? Perhaps the "usual" explanation is
> just an urban legend (I tend to be wary of such, because I have seen
> so many "well-known" facts rectified on this very newsgroup).
No urban legend, and a quite real danger.
Nasty accidents have happened this way.
And note that it is so dangerous precisely because
most of the water does not evaporate.
A steam jet from a test tube would dissipate rapidly,
thrown boiling water (or sulpheric acid :-(
may cross a labaratory.
Best,
Jan
Joseph.D.Warner
J. J. Lodder wrote:
> David Madore <david....@ens.fr> wrote:
>
>
>>J. J. Lodder in litteris <1fo6psu.1g5...@de-ster.xs4all.nl>
>>scripsit:
>>
>
> The explosive boil generates bubbles, which propel the liquid.
> An even more dangerous form of this experiment
> is to heat water in a test tube over a Bunsen burner.
> You need a very clean container and though.
> Making a cup of tea in the microwave is harmless.
>
Actually, on a few occasions the water in my coffee cup has been
superheated. When there is the introduction of sugar or cocoa the water
has violently boiled with about 60% of the content being expelled from
the cup.
>
>>Any comments on this experiment? Perhaps the "usual" explanation is
>>just an urban legend (I tend to be wary of such, because I have seen
>>so many "well-known" facts rectified on this very newsgroup).
>
On supercooling through a transition
It is fairly easy to supercool through many solid-state phase
transitions. I've had several experiences, when cooling from 300 K to 4
K, of the crystal supercooling. On the warm up cycle which is usually
much slower than the cool down cycle the crystal will shatter into
powder. That is always a bummer because you can't re-use the same sample
twice for your measurements.
J. J. Lodder
> J. J. Lodder wrote:
> > David Madore <david....@ens.fr> wrote:
> >
> >
> >>J. J. Lodder in litteris <1fo6psu.1g5...@de-ster.xs4all.nl>
> >>scripsit:
> >>
>
> >
> > The explosive boil generates bubbles, which propel the liquid.
> > An even more dangerous form of this experiment
> > is to heat water in a test tube over a Bunsen burner.
> > You need a very clean container and though.
> > Making a cup of tea in the microwave is harmless.
> >
>
> Actually, on a few occasions the water in my coffee cup has been
> superheated. When there is the introduction of sugar or cocoa the water
> has violently boiled with about 60% of the content being expelled from
> the cup.
Your cups must be cleaner than mine :-)
I use porcelain, not earthenware,
with inevitably some surface cracks in the glaze,
straight from the dishwasher, and the water always boils nicely.
Perhaps it is related to the fact that empty porcelain cups
will heat in the microwave without any water in them.
There must be a permanent electric dipole moment in the material.
Anybody more knowledgeable?
Jan
Danny McCarty
>
>Joseph.D.Warner <jwa...@grc.nasa.gov> wrote:
>
>> J. J. Lodder wrote:
>> > David Madore <david....@ens.fr> wrote:
>> >
>> >
>> >>J. J. Lodder in litteris <1fo6psu.1g5...@de-ster.xs4all.nl>
>> >>scripsit:
>> >>
>>
>> >
>> > The explosive boil generates bubbles, which propel the liquid.
>> > An even more dangerous form of this experiment
>> > is to heat water in a test tube over a Bunsen burner.
>> > You need a very clean container and though.
>> > Making a cup of tea in the microwave is harmless.
>> >
>>
>> Actually, on a few occasions the water in my coffee cup has been
>> superheated. When there is the introduction of sugar or cocoa the water
>> has violently boiled with about 60% of the content being expelled from
>> the cup.
>
>Your cups must be cleaner than mine :-)
Mine are, too, then. My reheated black coffee often begins boiling when I
add sugar or powdered cream- and it is in a porcelain cup. Only once did it
throw coffee on me, however...
Gordon D. Pusch
> Joseph.D.Warner <jwa...@grc.nasa.gov> wrote:
>> Actually, on a few occasions the water in my coffee cup has been
>> superheated. When there is the introduction of sugar or cocoa the water
>> has violently boiled with about 60% of the content being expelled from
>> the cup.
> Your cups must be cleaner than mine :-)
> I use porcelain, not earthenware,
> with inevitably some surface cracks in the glaze,
> straight from the dishwasher, and the water always boils nicely.
>
> Perhaps it is related to the fact that empty porcelain cups
> will heat in the microwave without any water in them.
> There must be a permanent electric dipole moment in the material.
Some glasses heat up in microwave ovens because they are ionic conductors;
perhaps this is also true of porcelain.
-- Gordon D. Pusch
perl -e '$_ = "gdpusch\@NO.xnet.SPAM.com\n"; s/NO\.//; s/SPAM\.//; print;'
Mike Darrett
[unnecessary wads of quoted text deleted]
> The explosive boil generates bubbles, which propel the liquid.
> An even more dangerous form of this experiment
> is to heat water in a test tube over a Bunsen burner.
> You need a very clean container and though.
> Making a cup of tea in the microwave is harmless.
>
> And note that it is so dangerous precisely because
> most of the water does not evaporate.
> A steam jet from a test tube would dissipate rapidly,
> thrown boiling water (or sulphuric acid :-(
> may cross a labaratory.
Reminds me of my college organic chemistry days. Professor told us to
use boiling chips, but I was in a hurry and refluxed my reactants in
my flask without them. Our professor never told us what the chips
were for, so I thought nothing of it. The reactants started to boil
violently, then finally "exploded", shooting my reactants upwards. No
one was hurt, but I made a nice spot on the ceiling.
That's what boiling chips are for - the rough silicon surface provides
nucleation sites, or sites for bubbles to form.
All the best,
Mike Darrett
Lars Henrik Mathiesen
>Daniel Grubb wrote:
>[snip]
>> Suppose you had 1cc of water and brought it down to the freezing point.
>>[snip]
>For the rest of your answer to be correct, this needs to be
>the freezing point *at the pressure which is finally reached*.
>With addition of that important proviso, your answer is a
>good one.
>Another way of putting it is, we can't tell what pressure will
>be reached until someone specifies the temperature. Btw note,
>at precisely 0 Celsius this problem has an easy answer.
As far as I can see, there will be a maximum pressure reached. You
need to find a diagram of density as a function of temperature and
pressure --- overlaid on a phase diagram, perhaps --- and follow a
line of constant density from your starting point towards lower
temperatures.
I haven't been able to find such a diagram on the internet, just phase
diagrams. But note that ice Ih/Ic exists only at pressures below 213
MPa, and the liquid phase only at temperatures above -22 C. These are
the only phases with densities less than 1g/cm^3, so 213MPa (2100 atm)
is an absolute upper limit.
My guess, however, is that the 1g/cm^3 isocurve will run at somewhat
lower pressures as the temperature decreases, until it reaches the ice
Ih/II interface. Since ice II has a higher density, an equilibrium
between the two phases will be maintained until ice IX enters the
picture.
Lars Mathiesen (U of Copenhagen CS Dep) <tho...@diku.dk> (Humour NOT marked)
Thomas Loerting
There has been some confusion about the different crystalline and
amorphous phases of ice in this thread. I myself have been active in
ice research for a couple of years and hope I can help to clarify some
issues:
To date there are 13 known crystalline forms of ice having roman
numerals: At ambient pressure the stable form is the common hexagonal
ice (Ih), thermodynamically slightly less stable (hence a metastable
form) is the cubic structure (Ic). Cooling hexagonal ice to very low
temperatures causes the protons to rearrange and the crystallographic
space group to be altered. This crystal structure is called Ice XI.
Under higher pressures there are different stable structures,
depending on temperature and pressure that are summarized in the phase
diagram of ice. These are Ices II, III, V, VI, VII, VIII and X. All
these structures can be recovered at ambient pressure, provided the
temperature is low enough to prevent any kinetics that would lead to
the thermodynamically stable forms. Ice VII for instance is so dense
that it actually consists of two interpenetrating networks of ice.
Ice X (stable above 100 GPa) is so dense that the concept of hydrogen
bond acceptor and donor breaks down - the proton sits exactly in the
middle between two oxygens. Vonnegut's Ice nine is just fantasy and
Ice IX is in fact proton-ordered Ice III. In addition to these stable
phases, there are two metastable phases of ice under pressure, namely
Ice IV and Ice XII. Ice XII (the 13th crystalline ice that was
discovered) was discovered in 1998 (see Nature 391, 268-270, (1998))
and its structure can be seen along with the one of Ice IV and the
phase diagram of ice on
http://www.cmmp.ucl.ac.uk/people/finney/soi.html
In addition to the 13 crystalline forms there are 5 amorphous forms of
solid water:
Amorphous solid water (ASW)
Hyperquenched glassy water (HGW)
low density amorphous ice (LDA)
high density amorphous ice (HDA) and
very high density amorphous ice (VHDA)
They differ in the way of preparation and in the physical properties
as measured e.g. by neutron diffraction. The first three are similar
in density to hexagonal ice, whereas HDA and VHDA would sink in water
(unless it did not melt first). VHDA has been discovered only
recently in our research group (Nature 420, 749 - 751 (2002)).
Of course you can prepare all the mentioned 18 forms also in their
different isotopic forms, but they are not new ices then since the
structure remains essentially the same.
All the high density forms of ice behave like popcorn when bringing
them to room temperature (since they transform to the lower density
stable forms) and are referred to non-scientifically as "popcorn
ices".
Hope this is helpful,
Thomas
John Baez
Calvin Ritchie <DonRit...@csWebmail.com> wrote:
>John Baez wrote
>>>Can anyone look up the density of ordinary D20 ice, divide
>>it by the density of ordinary H20 ice at the same temperature
>>and pressure, and compare *that* ratio to the ratio of their
>>molecular weights?
>On pg. 392-393 of Arnett's Chapter in "Solute-Solvent Interactions", Vol 1,
>(full reference was given in my earlier post in this thread) is a long table
>titled "Some Important Physical Properties of Light and Heavy Water".
Thanks!
>Molar Volumes [for H20 and D20]
> Solid at melting temp, cm^3/mole, 19.65, 19.679;
> Liquid at melting temp, cm^3/mole, 18.018, 18.118;
> Liquid at 25 C, cm^3/mole, 18.069, 18.134;
This part seems to have all the information I need.
Let me remind people about the game we were playing....
We wanted to know if the difference in densities between
H20 ice and D20 ice is completely explained by the difference
in mass between ordinary hydrogen and deuterium.
I initially predicted this would be true to an accuracy
of about 1 part in 1000 - since in fact a deuterium atom
is slightly smaller than an ordinary hydrogen atom, by
roughly that much.
Then I started backtracking when people pointed out that in
some circumstances - when the hydrogen nuclei are *moving* -
the properties of H20 and D20 can be much more drastically different.
Anyway: if the difference in density between H20 ice and
D20 ice were completely due to the difference in mass between
ordinary hydrogen and deuterium, these two forms of ice
would have the same number of molecules per volume. In
other words, they would have the same "molar volume".
Above we see that's true to about 1 part in 600:
19.679 / 19.65 = 1.0015
So, my guess was not too bad, but perhaps we can see some
effects due to moving nuclei.
For liquid water we should see bigger discrepancies, since
the nuclei are moving more. Let's see:
18.118 / 18.018 = 1.0056
Yup! That's for for water at its melting point. As we
heat it up, the nuclei move more so the discrepancy should
get bigger. At 25 C, we get:
18.134 / 18.069 = 1.0036
Hmm, no! Oh well. I feel I understand the rough picture -
*most* of density differences are merely due to mass differences
in the obvious way - but not the subtler discrepancies.
John Baez
In article <b0g143$fi0$1...@panther.uwo.ca>,
Thomas Loerting <loer...@MIT.EDU> wrote:
>I myself have been active in ice research for a couple of years
>and hope I can help to clarify some issues [....]
Thanks! Nice post! Just one question:
>Ice IX is in fact proton-ordered Ice III.
What does "proton-ordered" mean?
Calvin Ritchie
I had reported:
>>Molar Volumes [for H20 and D20]
>> Solid at melting temp, cm^3/mole, 19.65, 19.679;
>> Liquid at melting temp, cm^3/mole, 18.018, 18.118;
>> Liquid at 25 C, cm^3/mole, 18.069, 18.134;
To which John Baez responded:
>Anyway: if the difference in density between H20 ice and
>D20 ice were completely due to the difference in mass between
>ordinary hydrogen and deuterium, these two forms of ice
>would have the same number of molecules per volume. In
>other words, they would have the same "molar volume".
>
>Above we see that's true to about 1 part in 600:
>
>19.679 / 19.65 = 1.0015
>
>So, my guess was not too bad, but perhaps we can see some
>effects due to moving nuclei.
>
>For liquid water we should see bigger discrepancies, since
>the nuclei are moving more. Let's see:
>
>18.118 / 18.018 = 1.0056
>
>Yup! That's for for water at its melting point. As we
>heat it up, the nuclei move more so the discrepancy should
>get bigger. At 25 C, we get:
>
>18.134 / 18.069 = 1.0036
>
>Hmm, no! Oh well. I feel I understand the rough picture -
>*most* of density differences are merely due to mass differences
>in the obvious way - but not the subtler discrepancies.
>
I'm not sure how much difference it makes, but your comparisons aren't
completely legitimate. The first two comparisons are for the substances at
their RESPECTIVE melting points (i.e. 0 C for H2O and 3.81 C for D2O), while
the last one is for the two substances at the SAME temperature, 25 C.
Even so .... your comment about "subtler discrepancies" is prudent :-)
and probably applies to much (most?) of Chemistry.
Submitted Morning 21 Jan '03
Don Ritchie
DonRit...@csWebmail.com
John Devers
has been answered yet.
Do any of the phases or types you mention cover this?
Is H3O+ water? or another kind of chemical?
John Baez
John Devers <johnd...@froggy.com.au> wrote:
>[...] I mentioned H3O+ in post number 16 and I'm not sure if it
>has been answered yet.
You said something that didn't make sense, hence the lack of response.
>Do any of the phases or types you mention cover this?
No, of course not.
>Is H3O+ water? or another kind of chemical?
It's an "ion", not a "chemical" that has phases. You would
greatly profit from reading a chemistry book, but briefly:
Suppose you have a glass of water.
Each water molecule consists of two hydrogen atoms and an oxygen atom.
The hydrogen atom in turn consists of an electron and a proton. The
proton can be knocked off the water molecule, leaving a negatively
charged thing called OH-. A charged thing like this is not called a
"molecule" or a "chemical". It's called an "ion". This particular
ion OH- is called a "hydroxyl ion".
Meanwhile, the proton that got knocked off is called an H+ ion, or
"hydrogen ion". This ion will quickly stick onto another water molecule,
forming a positively charged ion called H3O+, or a "hydronium ion".
In ordinary liquid water this process happens all the time. Under
ordinary circumstances, at any given moment, one out of 550 million
water molecules is missing a proton, leaving a hydroxyl ion. There
will be a roughly equal number of hydronium ions.
We say ordinary water has "pH 7" because a liter of water consists
of 55 moles of H20 (a mole being a very large number), but only
one ten-millionth of a mole of H3O+, and one ten-millionth is 10^{-7}.
In an "acid" there are somewhat more H3O+ ions, hence a lower pH.
In a "base" there will be somewhat fewer H3O+ ions, hence a higher pH.
For more on this try:
http://dl.clackamas.cc.or.us/ch105-05/hydroniu.htm
and make sure to click on the links for related material.
Experts may prefer this other webpage:
http://www.nyu.edu/publicaffairs/newsreleases/tuckerman_proton.htm
which describes some recent computer simulations of liquid water
by Mark Tuckerman, Dominik Marx, Michele Parrinello, revealing
new information about how hydroxl ions move through water. The
pictures are worth a million words, but I'll quote some text:
......................................................................
In liquid water, H2O molecules form a complex network in which they
are connected by hydrogen bonds, a hydrogen atom between two
oxygen atoms in a roughly linear arrangement. Each water molecule
is surrounded on average by four other water molecules. Adding
or removing a proton (H+) in liquid water creates a defect in the
water network that is transported by making and breaking of bonds
within the system. H3O+, or hydronum ions, the fundamental component
in acids, are formed when protons are added and latch on to water
molecules. Hydronium ions are surrounded, on average, by three water
molecules.
Suppose water molecule A (see diagram panel a below) is connected
to H3O+ by a hydrogen bond and water molecule B is connected
to A by a hydrogen bond. Proton conduction in acids occurs when
the hydrogen bond between A and B breaks leaving A surrounded
by only two other water molecules and the H3O+ (panel b). This is
followed by a transfer of the proton from H3O+ to water molecule A
(panel c). The whole process takes only one millionth of one millionth
of a second.
Where H3O+ corresponds to an excess proton, hydroxide or OH- ions,
the fundamental component in basic solutions, were long thought to
constitute "proton holes" and, therefore, to have chemical properties
analogous to those of hydronium. In particular it was thought that
proton conduction in basic solutions could be viewed as a kind of
chemical "mirror image" of its acidic counterpart. The team's study
demonstrated that, in fact, no such simple chemical analogy exists
between H3O+ and OH-. For example, the team showed that OH- is
surrounded, on average, by 4-5 water molecules, quite unlike the
hydronium case. Moreover, proton conduction in bases requires more
complicated rearrangements of water molecules than in acids (see
diagram panels b and c below). Finally, the process is strongly
influenced by a phenomenon known as quantum tunneling, a phenomenon
that can occur at the microscopic level, which allows particles
to traverse spatial regions they normally should not, provided they
do it quickly enough.
John Devers
ba...@galaxy.ucr.edu (John Baez) wrote in message news:<b0lklo$q19$1...@glue.ucr.edu>...
> Meanwhile, the proton that got knocked off is called an H+ ion, or
> "hydrogen ion". This ion will quickly stick onto another water molecule,
> forming a positively charged ion called H3O+, or a "hydronium ion".
Ok, can you have pure hydronium ionic ice?
Can you isolate a thousand or so hydronium ions and bring them
together or does tunneling prevent them from remaining in that state?
John Baez
In article <6f838e26.03012...@posting.google.com>,
John Devers <johnd...@iprimus.com.au> wrote:
>ba...@galaxy.ucr.edu (John Baez) wrote in message
>news:<b0lklo$q19$1...@glue.ucr.edu>...
>> Meanwhile, the proton that got knocked off is called an H+ ion, or
>> "hydrogen ion". This ion will quickly stick onto another water molecule,
>> forming a positively charged ion called H3O+, or a "hydronium ion".
>Ok, can you have pure hydronium ionic ice?
No. Like most of the simpler ions, hydronium ions aren't something
that you can produce in pure form: they are extremely unstable shortlived
things.
>Can you isolate a thousand or so hydronium ions and bring them
>together [....]
No.
Studying a chemistry book would allow you to gain information
much more rapidly than asking questions like this. What you need
is an overall view, not the answers to lots of individual questions.
Uncle Al
If you don't mind a Coulomb explosion, sure. Chemists generally like
to see charge-compensating counterions (OH- won't work). Consider the
molar ratio of HF/H2O azeotrope, 38.26 wt-% HF. Is that close enough
to hydrated H3O+F-?
Calvin Ritchie
water, I happened today to be reading Jackson's "Classical Electrodynamics",
3rd Ed. and found, on pg. 315, a figure showing the absorption coefficient
of liquid water for wavelengths from >1 km to <1 Angstrom. There's actually
significant absorption all the way up in wavelength to slightly greater than
1 m, although the data become very sensitive to sample purity in that
region.
Also, in a much earlier post in this thread, I enquired if anyone could
verify or expand on a story I had once heard about radar trials, in the
early days, running into trouble from water absorption in a test over Boston
Harbor.
Jackson comments, on pg. 314:
"As the frequency increases toward 10^11 Hz, the absorption coefficient
increases rapidly to alpha=~10^4 m^-1, corresponding to an attenuation
length of 100 micrometers in liquid water. This is the well-known microwave
absorption by water. It is the phenomenon (in moist air) that terminated the
trend during World War II toward better and better resolution in radar by
going to shorter and shorter wavelengths."
Submitted Morning 26 Jan '03
Don Ritchie
DonRit...@csWebmail.com