Slashdot Mirror
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."
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.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
You missed the point. The neat thing is that water was liquid, and then they WARMED it, and it froze. It is just a gimmick, but it's not just that they managed to get it to freeze at a temperature below 0C. It's that, due to the interaction between temperature, charge, and the freezing point, they reversed the normal COLD-WARM SOLID-LIQUID order.
Slashdot headlines seem to do it now and then:
Canadian Scientists Regrow Teeth
French Scientists Link Higher BMI with Lower IQ
British Scientists Reverse Casimir Effect
German Physicists Claim Speed of Light Broken
Japanese Scientists Claim To Reconstruct Images From Brain Data
Italian Scientists Put Robot Spiders In Your Colon
etc.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
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.
Gravitation is a theory, not a fact.