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On the existence of two states in liquid water [pdf]

polymer.bu.edu

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Re: On the existence of two states in liquid water [pdf]

#11

Post by chadcmulligan »

mirimir wrote: post #8
chadcmulligan wrote: post #5

Earlier quoted context omitted.

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

Yes, but just what are those states? I see no explicit hypotheses. The clearest hint that I see is that the calculated dipole moment is 2.3 Ds at 0–60°C, "which is close to the value for ice", and 1.8 Ds at 60–100°C, "which is comparable to that reported for the vapour phase". Lower dipole moment means weaker hydrogen bonding, and less tetrahedral structure.

oh ok, I don't think they know yet - still some research to be done, the states have just been identified

Re: On the existence of two states in liquid water [pdf]

#12

Post by pizza »

simooooo wrote: post #7
chadcmulligan wrote: post #5

Earlier quoted context omitted.

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

Is this why hot water from a tap sounds notably different from cold?

It has to do with the size of the produced air bubbles and the mechanics of/lengths of the columns of falling water. But that said, this could play a bit of a role in those reasons.

Re: On the existence of two states in liquid water [pdf]

#14

Post by mathgenius »

John Baez has some interesting things to say about different structures that appear in water:

https://johncarlosbaez.wordpress.com/2013/11/29/water/

And these things have a very strong temperature dependence. I wonder if it has anything to do with the current discussion.

Re: On the existence of two states in liquid water [pdf]

#15

Post by carlob »

simooooo wrote: post #7
chadcmulligan wrote: post #5

Earlier quoted context omitted.

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

Is this why hot water from a tap sounds notably different from cold?

I don't think most taps reach 60° C. That would be 140° F in freedom units…

Re: On the existence of two states in liquid water [pdf]

#16

Post by the8472 »

mirimir wrote: post #8
chadcmulligan wrote: post #5

Earlier quoted context omitted.

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

Yes, but just what are those states? I see no explicit hypotheses. The clearest hint that I see is that the calculated dipole moment is 2.3 Ds at 0–60°C, "which is close to the value for ice", and 1.8 Ds at 60–100°C, "which is comparable to that reported for the vapour phase". Lower dipole moment means weaker hydrogen bonding, and less tetrahedral structure.

> Yes, but just what are those states?

That's covered in the introduction.

> Despite these efforts, the structure of liquid water is still not fully understood.

> This suggests that there are of two states in bulk liquid water that differ in the amount of their dipole moment. Unfortunately, a correlation between the dipole moment and the microscopic structure of these two states has not yet been determined.

Re: On the existence of two states in liquid water [pdf]

#17

Post by zeofig »

mirimir wrote: post #8
chadcmulligan wrote: post #5

Earlier quoted context omitted.

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

Yes, but just what are those states? I see no explicit hypotheses. The clearest hint that I see is that the calculated dipole moment is 2.3 Ds at 0–60°C, "which is close to the value for ice", and 1.8 Ds at 60–100°C, "which is comparable to that reported for the vapour phase". Lower dipole moment means weaker hydrogen bonding, and less tetrahedral structure.

The (purported) states are very similar. They have slightly thermal conductivities, electrical conductances etc. but still have all the usual properties of water (as they must, since we observe 60 degree and higher water all the time, and it still behaves like water).

Re: On the existence of two states in liquid water [pdf]

#18

Post by raverbashing »

chadcmulligan wrote: post #5
rosstex wrote: post #4

ELI5 please?

the conclusion probably says it all? "In conclusion, a review of the physical properties of water in the 0–100°C temperature range reveals a bilinear behaviour that defines a crossover temperature at 50 ± 10°C. This observation supports the hypothesis that there are two states of liquid water. We find that these two states play an important role in the thermal and optical properties of nanomedical systems. Finally, o…

I wonder if this is related to https://en.wikipedia.org/wiki/Mpemba_effect

Re: On the existence of two states in liquid water [pdf]

#19

Post by kmonad »

I think it is cool that there is evidence for these two states in water. I don't think, however, that the biological relevance was made particularly clear. There is hardly any life on earth for which these temperatures (upwards of 45C) play a role, and consequently, any effect on proteins would be 'out of context' within which protein function was under selective pressure. Whether or not protein stability is affected by these transitions of water states could therefore be purely coincidental. Having said this, however, one could perhaps learn more about how water affects protein function in 'normal' temperature ranges by breaking function with the other water state (but I don't understand this well enough to think of a way how to do this).

Re: On the existence of two states in liquid water [pdf]

#20

Post by amelius »

lisper wrote: post #3
wyager wrote: post #2

Interesting that the low end of this phase transition range coincides with the maximum safe temperature for mammals and birds. It could be that the delicate biological mechanisms we've developed over the years are highly sensitive to some of the bulk characteristics that change in this range.

The paper talks about this. It's not just mammals and birds, proteins in general become less stable over 60C: "This raises the question of whether temperature-driven structural changes in water affect biological macromolecules in aqueous solutions and in particular in proteins... It was found that the temperature stability range of the protein is confined to the reversible interval 45–65°C. ... In all cases the criti…

> This is probably why sous vide temperature is around 60C.

But why are sauna temperatures above this, being in the range of 70C-90C?

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