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

[biryokumaru]

So that's why my car gets covered in an inch-thick sheet of perfectly clear ice. That's always bothered me, thanks!

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.

Re:I could be stupid

[Ihmhi]

This could lead to a way to make ice cream without salt. They've managed to lower the freezing point of water without having to put any chemicals in the actual water itself.

Re:Israeli Scientists

[aysa]

I don't remember that stories about Italian/Japanese/German/British/French/Canadian scientists were ever questioned for mentioning the country of origin. Is the fact these scientists are Israeli disturbing you?

Re:Applications?

[aBaldrich]

They are scientists, not engineers.

Re:That's nothing.

[Anonymous Coward]

I take it you've never seen how wine is made. Those grapes have to get pressed somehow.

Whut?

[Quiet_Desperation]

It sounds like it freezes due to the change in charge, not because the water warms up. It's freezing in *spite* of the water warming. It's like they are just chasing the freezing point around.

You get the same effect when opening a highly chilled bottle of soda. It starts to freeze due to the release of carbonation, although the pressure change might come into play as well.

Re:Israeli Scientists

[Anonymous Coward]

You obviously forgot to mention the use of Christian little kids' blood to bake our Passover bread :)

It seems to me we're not particularly good at black-market organ harvesting, considering the bunch of Israelis lying around waiting for transplants.

Anyway, if you are true to your anti-Israeli cause, I'd recommend making sure you don't use any Israeli products. That includes, of course, intellectual-products, such as Intel Core2 chips, various medicines, economy models, and so forth.

Good luck !