What is the connection between phase changes in water and string theory?

[John100]

Why does water have a maximum density at +4 deg C ?
Is water unique in having this peak in density not at an extremity of the temperature range of a single (i.e. liquid in the case of water) state?
Is this property of water the single most important reason for life to have evolved on this planet?

 

[K^2]

Reason density decreases at temperatures above 4°C are the same as for any other material - thermal expansion.

Reason that density decreases at temperatures bellow 4°C is a bit more complicated. Ice has lower density than water because the ice crystal is fairly sparse. There is a lot of empty space within the crystal structure. At temperatures well above freezing, water molecules move individually. But near freezing, they start clustering up, forming structures very similar to ice crystal. These clusters are still very small and are free to move relative to each other, as well as constantly have pieces break off and attach, so water is still liquid. However, that organization leaves the same voids between water molecules as in ice crystal. As a result, density decreases.

Water is not the only substance that exhibits such property, but it is a very rare property. Off hand, I would not be able to name any other substance that does that. Water might be the only one that does that in "normal" temperature and pressure ranges, though.

 

[Andy Resnick]

Sodium triborate has a similar feature. IIRC, the relevant thermodynamic relation is

\Lambda_{V} \frac{\partial P}{\partial T}\geq 0

where \Lambda_{V} is the latent heat at constant volume. As water passes through 4 C at atmospheric pressure, the (V,T) point passes from a region where \Lambda_{V} > 0 to \Lambda_{V} < 0

 

[epenguin]

You are familiar with consequences of this fact?

That you can skate on ice. You couldn't on solid methane.

That there is a biologically important mixing up of lake water in cold/temperate regions in the spring called the spring overturn.

There must be similar in the sea somewheres but I haven't heard of it. Anyone?

 

[LURCH]

One of the consequences oft-quoted for biology is that ice floats. In most substances, the solid state i sheaveir than the liquid, and so it sinks. The fact that ice forms at the top of anybody of water means that a blanket i sin place to keep the entire water column from freezing. One of my profs here in Michigan said that, without this property, the Great Lakes would freeze solid from top to bottom every winter, and virtually nothing could survive there.

 

[K^2]

That you can skate on ice. You couldn't on solid methane.

Fortunately, few people want to.

It's not the result of water having lowest density at 4°C, though. It could have had lowest density at 0°C, and it would still work for ice skating.

 

[Studiot]

The 4 deg anomaly only applies to pure, or near pure water.

The density curve for seawater increases all the way down to freezing point, somewhere below zero.

 

[epenguin]

Fortunately, few people want to.

It's not the result of water having lowest density at 4°C, though. It could have had lowest density at 0°C, and it would still work for ice skating.

Right it is not the different densities of water but rather of ice being less dense than water. Though the two peculiarities are somewhat related according to previous post of K2.

 

[K^2]

Related, sure, but it's not guaranteed to actually create a minimum density at a point other than phase transition.

 

[steve.mileman]

I have tried to find logical and scientific answer to question of "What happens if you compress water". So far most answers have evaded the question by saying it cannot be done. This is so obviously not correct. To be fair I think the question ought to be broken down into two:

(a) When does compressed water cease to be water?

(b) What happens to water (or any liquid) when it is compressed let say first to the stage when it ceases to be water and second to its limit.

Please no hogwash about it not being possible. Put the mass of the universe on a drop of water and tell me that the drop will survive in its original state.

Here is my lawman's attempt:

1. The water heats up but because it cannot expand, being compressed it cannot evaporate.

2. There is a heat build up inside the compressed mass.

3. At some point the mass of water will have to lose its ability to resist the compression of its molecules and breach the molecular forces.

4. Because it takes a comparatively large force to break the molecular bonds, when they yield they collapse.

5. The resulting "collapse" is a fusion.

from http://en.wikipedia.org/wiki/Nuclear_fusion

“In the simplest case of hydrogen fusion, two protons have to be brought close enough for the weak nuclear force to convert either of the identical protons into a neutron forming the hydrogen isotope deuterium. In more complex cases of heavy ion fusion involving two or more nucleons, the reaction mechanism is different, but the same result occurs - one of combining smaller nuclei into larger nuclei.”HOWEVER, we now have water's molecular structure breaking down into component atoms at extremely high temperatures and high energy levels. But the hydrogen and oxygen atoms are surely like to respond differently.

The weakest bond of the threesome will surely be the oxygen bonds. As soon as these are destroyed the mass can no longer be called "water" because it is no longer h20.

But the state of free single oxygen and hydrogen molecules is not stable, being under continued pressure.
A The next bond that will break under this continued increase of heat and pressure will be ….

B The remaining components will react to the new state in what way …C The combination of the above will react as follows:

 

[sophiecentaur]

Why are you bringing Nuclear Forces into this discussion? The energies involved take it way out of the league of chemical / molecular behaviour.
Where does the concept of "fusion" come into a re-alignment of inter atomic forces due to external pressure or a change in temperature? You start with Oxygen and Hydrogen and you end up with Oxygen and Hydrogen. No transmutation or anything else fancy.

 

[Andy Resnick]

I have tried to find logical and scientific answer to question of "What happens if you compress water". So far most answers have evaded the question by saying it cannot be done.

I haven't seen those responses. Water can be compressed; the bulk modulus is around 2.2 GPa.

Here's a partial phase diagram for water:

http://hpc.amu.edu.pl/~armand/blog/wp-content/uploads/2008/08/ice_phase_diagram.jpg

As you can see, when you compress water enough, it turns to ice.

 

[steve.mileman]

Sohie, thanks for your reply. Please bear with me as a layman.

Would I be wrong in suggesting that a liquid is compressible (capable of withstanding a reduction in volume) up to a point that does not break the electrochemical bonds between molecules. In other words the liquid will have a coefficient of expansion in the same way as a solid does. I expect that liquids and solids behave in similar ways because they are dependant on temperature and pressure for their state.

If the volume of a liquid is decreased below a certain point it must surely be at the expense of those electrochemical bonds.

I am wondering what happens when one of the factors: pressure, temperature and volume is placed at an extreme end of the scale.

Suppose that the volume of water is 100 cm and it is reduced (in some hypothetical manner) to 1cm. What would the final result be? I think that the result of particles forced to collide at greater energy levels than are characteristic for the substance must surely have nuclear consequences and change the substance.

I saw an article at http://www.reciprocalsystem.com/ls/paper04.htm and wondered if it would help. I need to study it carefully but I would be grateful for any assistance.

 

[Danger]

Water is an incredible substance. It is one of very few that can naturally exist in 3 phases within the same environment (solid, liquid, and gas), which is one of the reasons that the "Goldilocks Zone" for the possibility of Earth-like life was established based upon it. While other substances can duplicate that, none of them are properly reactive with other substances.
While I'm a heavy Scotch and beer drinker, my answer to the old "what drink would you take with you if you were to be stranded on an island?" is always "potable water". It's the basis of life as we know it, and is truly remarkable.

 

[steve.mileman]

I haven't seen those responses. Water can be compressed; the bulk modulus is around 2.2 GPa.

Here's a partial phase diagram for water:

http://hpc.amu.edu.pl/~armand/blog/wp-content/uploads/2008/08/ice_phase_diagram.jpg

As you can see, when you compress water enough, it turns to ice.

Andy,

It sounds logical for liquids in general that they would change state to solids and then break up. Thanks for the diagram. Let me try to get my mind around how a pressure increase in the case of water results in ice which would have a lower density. Its weird in the case of water but logical.

I must say that on posing the question I realize that we must possibly define "compressible" as a reduction in volume and not necessarily an increase in surrounding pressure. I think that my first question relates to what happens inside the volume/mass of water. But the phase diagram is still pertinent, I think.

The second part of my question is what happens at the extremes of reduction of volume and temperature. Of course I understand that the substance is no longer water or iced water. I am interested in the 'edge": when the water or any liquid is close to losing its molecular definition.

On some planets, ice exists at many hundreds of degrees below Earthly zero but how far can you take such a state? At some point the state must be disrupted.

 

[steve.mileman]

Water is an incredible substance.

Thanks Danger.

I certainly wouldn't want to take ether with my whiskey even at home. But you are right not much else mixes palatably with whiskey at our ambient temperatures and pressures.

But now consider this:

1. Reduce the temp of water and it expands and turns into ice which floats on the whiskey.

2. Compress the water and Andy's diagram shows that water will form ice which floats on the whiskey.

3. Reduce the surrounding pressure of water and it boils and floats on the whiskey.

4. Skate on (even thin) ice and it melts with the increase of pressure but if warmer than the whiskey, it will also float on the whiskey.



Now how do we reconcile 2 and 4 above.

Especially when even humans can float on whiskey.

Aside, but seriously Danger, I don't want to derogate from the sincerity of my questions but, water certainly has a special place in our solar system. Elsewhere, I have to wonder if alcohol is not as good. Did you know that astronomers have spotted a cloud of methyl alcohol that measures 463 billion km across in a region of the Milky Way called W3(OH). Now I wouldn't want to drink whiskey made from methyl alcohol, but you have to ask if that might not be some other life form's cup of tea.

 

[Danger]

Steve, I don't doubt that methyl alcohol was one of the instigators of life on Earth, along with methane, ammonia, etc..
My reference to the reactivity of water was not in fact based upon its compatibility with Scotch, although I obviously appreciate that. I was, rather, pointing out that it is almost a universal solvent for incorporating things like salts and amino acids and gases and damned near everything else into it's environment, within which they can mingle enough to produce life.

 

[rcgldr]

What happens if you compress water.

If you cool it while compressed to form ice, you get different crystal forms of ice, and these are denser than water. Fortunately, these type of pressures don't exist on the Earth even at the bottom of the ice shelf at Antarctica.

http://en.wikipedia.org/wiki/Ice#Phases

http://www.lsbu.ac.uk/water/ice.html

 

[nucleus]

http://www.dhmo.org/

 

[steve.mileman]

"Danger;3027050]Steve, I don't doubt that methyl alcohol "

Danger, I agree with you about water. I was just having some fun with your amusing reference to the whisky which lead me to some interesting thoughts. Thanks for that.

I agree that water is an amazing substance and I would not be surprised if, in competition for the most versatile life support substance in the universe, it was selected as the number 1. There must be a winner I suppose.

You are so right that water is a great facilitator; a simple substance, with properties such as an inability (in Earth conditions) to act as a solvent for oil and fatty substances and an ability to expand on freezing. Then. how important is the latent period between 0 and 4 deg C when it hangs around and waits for the dust settle. Imagine the problems if the change of state were to take place suddenly. I suppose we would have no need for frozen fish factories.

As a perhaps naive over-simplification, I place water’s inability to mix with fat as one the top reasons for the support of life. for that reason membranes can be created to serve as containers to divide into cellular forms that can permit a flow of energy, chemicals, or water to pass from cell to cell; a basic interactive two-way communication system.

At the philosophical heart of life must surely be the ability of two independent cells (containers of properties) to cooperated or compete.

 

[Danger]

Imagine the problems if the change of state were to take place suddenly. I suppose we would have no need for frozen fish factories.

I severely regret that I'm so tired, because I would really love to get into a big-time debate with you. Unfortunately, my current level of inebriation forestalls that for a tad.

 

[steve.mileman]

Danger, I suspect our focus is failing on the maximum density of water. Let's start another thread if you like.

On this one I would like to get back to exploring the maximum density of water and pondering what happens at that boundary. Let's call it the event horizon.

I love your humour thanks.

 

[Danger]

Danger, I suspect our focus is failing on the maximum density of water. Let's start another thread if you like.

On this one I would like to get back to exploring the maximum density of water and pondering what happens at that boundary. Let's call it the event horizon.

I love your humour thanks.

Actually, the best thing overall is if I just bow out of this one, which I am doing right now. I'll continue monitoring this thread, because it is educational, but it might be a long time before I post in it again, just because I am not qualified to do so.

 

[steve.mileman]

Sophie asked why get into a nuclear debate.

Here is an answer that suggest that is is in fact where the question must be taken

http://www.Newton.dep.anl.gov/askasci/eng99/eng99530.htm"That is a bit oversimplified, though. The simple phases (solid, liquid, etc)
lose their distinctions at these extreme conditions. Our common-sense
knowledge of how things works tends to break down. We cannot actually achieve
0K experimentally anyway, and even if we could, the thermodynamics would
make things act really squirrely. At massive pressures, the terms solid and
liquid start to lose meaning. You have a system so highly constrained that
it is no longer hydrogen bonding or van der Waals forces, but nuclear
repulsive forces that dominate the structure. The fact that molecules cannot
jump around as readily is what makes a solid a solid, although technically
molecules can jump around, just at a much slower rate. But I digress...

And, for all you ever wanted to know about water, here is the terrific site
from which I got the phase diagram:

http://www.lsbu.ac.uk/water/index.html

Hope this helps,
Burr Zimmerman"

 

[steve.mileman]

While water is still water its solid form is ice. Ice seems to exist in 12 different forms.

Form this website - http://www.lsbu.ac.uk/water/phase.html

"The physical properties of water close to the critical point (near-critical) are particularly strongly affected [677], Extreme density fluctuations around the critical point causes opalescent turbidity. Many properties of cold liquid water change above about 200 MPa (for example, viscosity, self-diffusion, compressibility, Raman spectra and molecular separation), which may be explained by the presence of a high density liquid phase containing interpenetrating hydrogen bonds. The chemical properties of water are also greatly changed at high temperatures and pressures due to the changes in ionization, solubility, diffusivity and reactivity due to decreasing hydrogen-bonding"

At this stage of the phase we are still just bend the hydrogen bonds. At same stage,they will surely break. There must be a view on that break-down stage.

 

[steve.mileman]

Another quote from http://www.lsbu.ac.uk/water/explan2.html#density


"It is evident that most anomalous behavior must involve a quite sudden discontinuity at about the homogeneous nucleation temperature (~228 K, where the densities of supercooled water and ice approach) as the tetrahedrally arranged hydrogen bonding approaches its limit (two acceptor and two donor hydrogen bonds per water molecule) and no further density reduction is possible without an energetically unfavorable stretching (or breaking) of the bonds"

"Supercooled and cold (< 3.984°C) liquid water both contract on heating [68]. As the temperature decreases, the cluster equilibrium shifts towards the expanded, more open, structure (for example, ES), which more than compensates for any decrease in volume due to the reduction in the kinetic energy of the molecules."

I think we are getting somewhere now.

 

[steve.mileman]

Looks like we are now getting much closer to looking at the question than the simple proposition that "water has a maximum density full stop". Still I am not getting to the rock bottom of the question and I wonder if it is not going to turn into an "event" that will force atomic relationships that have a variety of results.

This is the conclusion of an article by V. Teboul http://arxiv.org/ftp/cond-mat/papers/0702/0702551.pdf



"We have studied the evolution of dynamical heterogeneity and string-like cooperative motions when supercooled water is confined into a pore a few nanometers across.
The modification of the dynamics with confinement is usually seen as an indirect probe of the correlation length limitation by the pore radius, leading to an expected
acceleration of the dynamics instead of the slowing down that is observed in most simulations and experiments. However we have found an increase of the correlation
lengths when water is confined inside the pore, instead of the expected decrease. And this result may shed new light on the relationship between the modification of the
dynamical properties and the auto-organization of the most and of the least mobile molecules (the so called dynamical heterogeneities). We have found that, at constant
temperature, the dynamical heterogeneities increase when water is confined inside the pore. Using then a constant diffusion coefficient instead of a constant temperature
we have also observed an increase of the dynamical heterogeneity with confinement. This result shows that the increase of the cooperativity is not a simple consequence
of the slowing down of the dynamics."

 

[Danger]

Sophie asked why get into a nuclear debate.

Here is an answer that suggest that is is in fact where the question must be taken

http://www.Newton.dep.anl.gov/askasci/eng99/eng99530.htm"That is a bit oversimplified, though. The simple phases (solid, liquid, etc)
lose their distinctions at these extreme conditions. Our common-sense
knowledge of how things works tends to break down. We cannot actually achieve
0K experimentally anyway, and even if we could, the thermodynamics would
make things act really squirrely. At massive pressures, the terms solid and
liquid start to lose meaning. You have a system so highly constrained that
it is no longer hydrogen bonding or van der Waals forces, but nuclear
repulsive forces that dominate the structure. The fact that molecules cannot
jump around as readily is what makes a solid a solid, although technically
molecules can jump around, just at a much slower rate. But I digress...

And, for all you ever wanted to know about water, here is the terrific site
from which I got the phase diagram:

http://www.lsbu.ac.uk/water/index.html

Hope this helps,
Burr Zimmerman"

I do, however, have to respond to this. I'm pretty sure that the water in my taps and in my drinking jug is liquid, that the water in my freezer is frozen, and that what spews out of my kettle is vapour. I don't consider any of those to be "extreme" conditions. Am I missing something?

 

[steve.mileman]

Danger, now I see where your name comes from. What you are missing is both the question and the answer. I don't think you ought to so sure of what comes out of a spout. There is a lot in the mix but it’s not all water.

More importantly, on the inside of you whiskey glass you have ice from your freezer, but it’s not long before its water. On the outside of your cold whiskey is water that did not come from your tap or from the whiskey inside the glass. In fact a lot of that water probably came from your own body that loses an incredible amount of water to the air: water that may have come from the Jack Daniels factory.

Glass itself is a liquid but its better employed to contain the whiskey and water than to mix with it.

So right there in you very own kitchen you have multitude of different states of water and liquids that will quite suitable contain another liquid; each substance and each state with different characteristics. As the man says: the difference between sold states and liquid states is not always clearly defined.

You were taught that when you compress something, it heats up, but we are told that water will turn to 12 different states of ice. Only one state is suitable to use with whiskey; the last state will probably freeze the alcohol out of the whiskey.

You also know that when you are skating on any thickness of ice in normal Earth conditions the pressure will melt it. Now how do we explain that pressure can both melt ice and create it?

Still water is a happy union of two hydrogens and one oxygen atom that are in a harmonious and stable relationship on this planet. But conditions elsewhere in relatively supercooled and superheated states pose some very interesting questions about the character tics of the various states of water.

I am sure you have heard of the danger of superheating water in your microwave. You can raise the temperature of water substantially higher than 100 deg C in the microwave and yet leave its observable state unchanged. Of course the moment you disturbed the molecules they explode into steam expanding at 1600 times the equivalent volume of water.

But this discussion is now taking us to the lower end of the density scale and I want to go to (no past) the highest density of water/ice and see what happens when you look back over the “event horizon”.

As you so aptly say: Full Flaps ... we're in wrong place

 

[Hootenanny]

Glass itself is a liquid but its better employed to contain the whiskey and water than to mix with it.

Glass is certainly not a liquid at room temperature.

 

[Borek]

Steve, I guess the real question here is at what pressure we will stop calling substance a water. We know matter can be squeezed to the limits seen in neutron stars, which is around 10¹⁷ kg/m³. Somewhere between 10³ kg/m³ and 10¹⁷ kg/m³ chemical substance stops to be a chemical substance.

 

[steve.mileman]

On at least one level about changes of state in water



Maxim Vengerov, the violinist said that he remembered that as a child in Siberia where he lived and learned to play the violin, the warmest place in the house was in the fridge where it was only 4 deg C. Outside it was -40.

 

[steve.mileman]

Glass is certainly not a liquid at room temperature.

There I beg to differ. It may flow very slowly but a liquid flows and that is what glass does. There are many examples in old window panes that are thicker at than at the bottom. But its easy to prove.

 

[Borek]

There I beg to differ. It may flow very slowly but a liquid flows and that is what glass does. There are many examples in old window panes that are thicker at than at the bottom. But its easy to prove.

Unless it is just an urban legend...

 

[Hootenanny]

There I beg to differ. It may flow very slowly but a liquid flows and that is what glass does. There are many examples in old window panes that are thicker at than at the bottom. But its easy to prove.

You can beg all you like, but as Borek says,

Unless it is just an urban legend...

it is just an urban legend.

Glass is an amorphous solid, which contrary to popular belief, does not flow to any appreciable extent. The thicker bottomed windows pains are a result of the pre-float line manufacturing processes.

 

[steve.mileman]

Steve, I guess the real question here is at what pressure we will stop calling substance a water.

Borek, thank you. I believe you are right that we ought to define the question more accurately if we can.

Reading Teboul's article (referred to above in one of my posts,) the problem is that in both bulk and hydrophilic nanopore simulations there were differences as a result of heterogeneity within the samples themselves.

We are really looking at the variety of states in which two hydrogen atoms and one oxygen can exist. We know that in one state we can simply call it “water” because we can see it and drink it and we don’t necessarily have to worry about how it behaves at a molecular level. Yet we know that in membranes (at the least for us as living organisms) we are fortunate the water is capable of it’s peculiar behave.

Down the tumultuous scale to rock bottom, these atoms are not as happy to share a confined space as Teboul says correlates with work on confined Lennard-Jones liquids.

My question is less about the relationship than about the divorce.

 

[steve.mileman]

You can beg all you like,

My apologies Hootenanny. I was too hasty. I want to focus on water, but since you raise it and I now I have to be suspicious at best about the ancient window pane through which I have seen my own distortion, let me say that there appear to be different views. Check out : http://www.xs4all.nl/~johanw/PhysFAQ/General/Glass/glass.html

“It would be convenient if we could conclude that glassy materials changed from being a supercooled liquid to an amorphous solid at the glass transition, but this is very difficult to justify. Polymerised materials such as rubber show a clear glass transition at low temperatures but are normally considered to be solid in both the glass and rubber conditions.
It is sometimes said that glass is therefore neither a liquid nor a solid. It has a distinctly different structure with properties of both liquids and solids. Not everyone agrees with this terminology.”

But I have to concede that it is not a simple question of being a liquid.

 

[Hootenanny]

My apologies Hootenanny. I was too hasty. I want to focus on water, but since you raise it and I now I have to be suspicious at best about the ancient window pane through which I have seen my own distortion, let me say that there appear to be different views. Check out : http://www.xs4all.nl/~johanw/PhysFAQ/General/Glass/glass.html

“It would be convenient if we could conclude that glassy materials changed from being a supercooled liquid to an amorphous solid at the glass transition, but this is very difficult to justify. Polymerised materials such as rubber show a clear glass transition at low temperatures but are normally considered to be solid in both the glass and rubber conditions.
It is sometimes said that glass is therefore neither a liquid nor a solid. It has a distinctly different structure with properties of both liquids and solids. Not everyone agrees with this terminology.”

But I have to concede that it is not a simple question of being a liquid.

I am more than happy to concede that there are different interpretations of the state of glass. Moreover, I am happy to have an in-depth debate on the merits of classifying glass, and other materials in general, into strict categories. I was merely, objecting to the assertion that glass is a super-cooled liquid, without any qualification.

 

[steve.mileman]

I was merely, objecting to the assertion that glass is a super-cooled liquid, without any qualification.

The question could be up for debate but I am inclined to agree having looked at the Scientific American article. A few things stand out though: I would have thought that to behave as a liquid it would have to flow within a fairly short space of time. The difficult of molecules being able to pass one another easily probably makes it behave observably like a solid rather than a liquid. I like the Scientific American quote for the moment.


"Glass, however, is actually neither a liquid—supercooled or otherwise—nor a solid. It is an amorphous solid—a state somewhere between those two states of matter. And yet glass's liquidlike properties are not enough to explain the thicker-bottomed windows, because glass atoms move too slowly for changes to be visible."

 

[Studiot]

For your information, Steve, even solids flow, albeit not as readily as fluids.

But what, exactly, is now your point or question?

 

[Danger]

Thank you, both Hoot and Borek.
Steve, can you please, just for the sake of this thread, disregard the fact that I'm an alcoholic? Even when I'm as pissed as a nit, I do try to maintain a scientific approach to things. I am not the one who instigated a reference to whiskey in this thread. (And by the bye, the suggestion that I would drink JD bourbon is very insulting. That's a poor substitute for real whisky.)

 

[steve.mileman]

QUOTE=Studiot;3028493]For your information, Steve, even solids flow, albeit not as readily as fluids.



But what, exactly, is now your point or question?[/QUOTE]



Yes Studiot, but we are way off my question answering anything but:



Three posts that may resurrect the question:



Steve:



We are really looking at the variety of states in which two hydrogen atoms and one oxygen can exist. We know that in one state we can simply call it “water” because we can see it and drink it and we don’t necessarily have to worry about how it behaves at a molecular level. Yet we know that in membranes (at the least for us as living organisms) we are fortunate the water is capable of it’s peculiar behave.



Down the tumultuous scale to rock bottom, these atoms are not as happy to share a confined space as Teboul says correlates with work on confined Lennard-Jones liquids.



My question is less about the relationship than about the divorce.



The second Last Post.



Borak says:

Steve, I guess the real question here is at what pressure we will stop calling substance a water. We know matter can be squeezed to the limits seen in neutron stars, which is around 1017 kg/m3. Somewhere between 103 kg/m3 and 1017 kg/m3 chemical substance stops to be a chemical substance.



The Last Post: A return to the question under debate in relation to water:



Steve Quoted



"It is evident that most anomalous behavior must involve a quite sudden discontinuity at about the homogeneous nucleation temperature (~228 K, where the densities of supercooled water and ice approach) as the tetrahedrally arranged hydrogen bonding approaches its limit (two acceptor and two donor hydrogen bonds per water molecule) and no further density reduction is possible without an energetically unfavorable stretching (or breaking) of the bonds"

"Supercooled and cold (< 3.984°C) liquid water both contract on heating [68]. As the temperature decreases, the cluster equilibrium shifts towards the expanded, more open, structure (for example, ES), which more than compensates for any decrease in volume due to the reduction in the kinetic energy of the molecules."



Steve now says:

And then what? Let's take the last statement to its next level. My gut is saying that the distortion of atomic bonds referred to Teboul, (I think) should cause some interesting new characteristic to arise. For the sake of the debate, let's still call this water in deference to Borek’s point on the definition of water.

 

[steve.mileman]

Thank you, both Hoot and Borek.
Steve, can you please, just for the sake of this thread, disregard the fact that I'm an alcoholic?

Danger,

Never fear! I hope I sussed you out at the beginning. I don't believe a word of what you say about your own "state" other than I suspect that you watch with a keen and interested scientific eye, while lightning the mood with some banter. I really enjoy it and I am waiting for the invertible spot-on observation from you.

As the the JD I have to say that I think perceptions of both quality and state are relative. I bet that exposed to more JD you would abandon all competing views. If you say "no" then I would be interested to know why you think those views may not change.

Thanks for being there.

 

[steve.mileman]

Steve, even solids flow.

The difference between solid and liquid states is not clearly defined. I think we have to leave the "glass" discussion which was a mistake for me to introduce.

But let's bear in mind that we are looking beyond the distinction between solid and liquid. We are looking into a state where I suspect that we will find several intermediate states that have different characteristics within different time frames. I hope will capture the interest of someone who can look at the change of state as it approaches a break or bending in the forces. Those conditions in which hydrogen and oxygen can no longer bond. We have prescribed that they cannot escape (immediately and hypothetically) so we can look at how they attempt to escape and under what conditions. How those bonds are stretched until they break?

It’s like the several different states of ice water. Let’s not call all states of ice just "ice" so to speak. That prevents us from asking how each state distinguishes itself from the other. I expect we will several states of solid and transitions between those states.

 

[steve.mileman]

So there are no more takers ... ?

Well here is David Peat's view in “Superstrings”:

"Below the Planck length, we would not expect to see many of the usually space-time properties; there would be no sense of length, no measure or metric to the space."

“…at around Planck length, something like a phase transition occurs. [A phase transition takes please when ice changes into liquid water or water into steam. While a dramatic change occurs at 0 degrees C or 100 degrees C, the “essence “ of water in its molecular form does not, however, change, so that “water” could be said to exist in several phases or forms.}

“Above Planck length distance has a meaning: below the Planck length physicists would have to reply on topological properties”

Peat gives “carbon” as another example of the many phases in which this element can exist. The phase is which it breaks down is where relativity and quantum states are difficult to describe (or imagine) in 4 dimensions.

One theory of the phase change below Planck length is that the molecular structures break down into superstrings that are best described in more than 4 dimensions and probably work best in 10 dimensions. In any event I would expect that strange things begin to occur in water as it approaches a very dense state. I wonder if the same thing happens to all molecules as they breakdown. Perhaps there is a similar window period between very dense and breaking apart.

Is there anyone who has an up-to-date view on this?

 

[alxm]

Peat gives “carbon” as another example of the many phases in which this element can exist. The phase is which it breaks down is where relativity and quantum states are difficult to describe (or imagine) in 4 dimensions.

That sounds like a load of nonsense. It seems to me Peat made an analogy to phase changes to describe symmetry breaking. That does not mean he's talking about chemical phase transitions, which have nothing to do with string theory at all, and are completely understood in our current understanding of quantum mechanics*.

Superstrings, if they exist, and the Planck length are farther removed from the atomic scale than the atomic scale is from the everyday scale. It's like claiming the motion of billiard balls is quantum-mechanical.

* Which does not mean there aren't things we don't know about phase changes. In fact, there's plenty we don't know about phase changes. But the fundamental interactions involved in them are completely known, and hardly require General Relativity to explain.