Israeli Scientists Freeze Water By Warming It

ccktech writes "As reported by NPR and Chemistry world, the journal Science has a paper by David Ehre, Etay Lavert, Meir Lahav, and Igor Lubomirsky [note: abstract online; payment required to read the full paper] of Israel's Weizmann Institute, who have figured out a way to freeze pure water by warming it up. The trick is that pure water has different freezing points depending on the electrical charge of the surface it resides on. They found out that a negatively charged surface causes water to freeze at a lower temperature than a positively charged surface. By putting water on the pyroelectric material Lithium Tantalate, which has a negative charge when cooler but a positive change when warmer; water would remain a liquid down to -17 degrees C., and then freeze when the substrate and water were warmed up and the charge changed to positive, where water freezes at -7 degrees C."

Comments

I could be stupid

[PakProtector]

But I was expecting something along the lines of "Researchers manage to make water freeze at greater than 0C," instead of "Researchers manage to make water freeze below normal freezing temperature."

Haven't they ever heard of salt? Or Anti-freeze?

Re:I could be stupid

[SimonTheSoundMan]

I thought pure water doesn't go solid, not until an impurity starts crystal formation that turns the water into a solid?

Re:I could be stupid

[Trepidity]

Salt and anti-freeze just have typical freezing-point depression; there's no way to use them to produce a situation where water that is a stable liquid at one temperature will turn solid if you increase the temperature. The situation in this experiment is that water that's liquid at -17 C will freeze as you head it up towards -7 C.

Re:I could be stupid

[Ardeaem]

You missed the point. The neat thing is that water was liquid, and then they WARMED it, and it froze. It is just a gimmick, but it's not just that they managed to get it to freeze at a temperature below 0C. It's that, due to the interaction between temperature, charge, and the freezing point, they reversed the normal COLD-WARM SOLID-LIQUID order.

Re:I could be stupid

[Linzer]

I thought pure water doesn't go solid, not until an impurity starts crystal formation that turns the water into a solid?

In many cases, the surface of the container has defects which can play that role.

Re:I could be stupid

[pj81381]

I thought pure water doesn't go solid, not until an impurity starts crystal formation that turns the water into a solid?

This comment seems really unintuitive so I looked around a little. Ice can actually form entirely without crystallization, by cooling it to ~137 C in a matter of milliseconds. The article also mentions that "pure water, in the absence of any nucleating surface, can remain in a supercooled liquid state down to temperatures as low as -40C". I guess that means that pure water will begin crystallizing at this temperature anyway.

Re:I could be stupid

[Gibbs-Duhem]

Exactly, this is well known, and is the difference between homogeneous nucleation caused by the massive undercooling providing the energy to nucleate ice spontaneously versus heterogeneous nucleation which requires much less free energy and occurs dependent on surfaces.

It is not scientifically interesting that they warmed it to get it to freeze, that's just a comparison of freezing points... it's interesting that the charge of the surface modified the freezing/nucleation point. Frankly, I am amazed that this was published in Science; it seems like worthwhile research, but for a journal more like, say... applied physics letters or a more specific interest journal. Kudos to the researchers for managing to spin it as a general-interest paper when it is in fact a fairly simple observation of an obscure phenomena.

Progress

[brettz9]

It's not quite Hell, but it's an impressive step in that direction...

Israeli Scientists

[Anonymous Coward]

I don't remember the science story yesterday Physicists Discover How To Teleport Energy being called Japanese Physicists Discover How To Teleport Energy. Is the fact these scientists are Israeli title worthy?

Re:Israeli Scientists

[Spad]

Obviously Chemists are more nationalistic than Physicists...

Re:Israeli Scientists

[Trepidity]

Slashdot headlines seem to do it now and then:

Canadian Scientists Regrow Teeth

French Scientists Link Higher BMI with Lower IQ

British Scientists Reverse Casimir Effect

German Physicists Claim Speed of Light Broken

Japanese Scientists Claim To Reconstruct Images From Brain Data

Italian Scientists Put Robot Spiders In Your Colon

etc.

Nothing new I have noticed this with my beer ;-))

[ls671]

When I put a beer in the freezer too long but not that long, when I take it out of the freezer, I can see it is pretty 100% liquid inside the bottle. Now, taking it out of the freezer makes it warmer and opening it even warmer due to air circulation inside the bottle.

Well, when I open it, it turns to ice so I make my beer freeze by making it warmer so nothing new here ;--))))

Very seriously, I swear this is true but I understand it could be due to other factors that the ones described in TFA like pressure inside the bottle but I thought it would interesting to mention anyway.

Haven't anybody else seen their beer freeze in their hand while opening it just after it has been in the freezer although it was in a liquid state when they actually took it out of the freezer ?

That's nothing.

[Timosch]

One of these guys managed to turn water into wine 2000 years ago...

Ah, I see you are an american

[SmallFurryCreature]

You clearly must be an American, since you compare beer to water. Over here in the old world, we know there is a difference by the taste for one.

Re:Dowsing

[Smallpond]

A dowser was working Down Under
when his failure caused him to ponder
"the charge on me watta
was more than it oughta.
So I couldn't tell lightning from thunder."

Re:Applications?

[PopeRatzo]

but are there some cool real-world applications I'm not thinking of?

A pyroelectric lithium tantalate ice cube tray? In animal shapes?