Learn more physics!
Is there anything that would raise the freezing point of water so things would freeze above 32 degrees?
- Matthew (age 27)
For something to dissolve in water, the water must prefer being in the solution to staying apart as pure water. In technical terms, the solute lowers the chemical potential of the liquid water. Unless the solute lowered the chemical potential of the solid ice even more, adding some solute will always favor the liquid, lowering the freezing point. Since the solid ice is a regular pattern of molecules, small amounts of solute break up the pattern, and are excluded from the ice. A few examples are sea water (with salt), sugar water, and water with alcohol. In all three cases, adding the solute lowers the freezing point. Here is a link to a previous question that was asked on our site that gives a more thorough explanation. http://van.physics.illinois.edu/qa/listing.php?id=16021
The only exception to this argument would be some molecule that fit into the ice structure even better than ordinary water. Actually, water made with the deuterium isotope of hydrogen rather than ordinary hydrogen fits the bill. This "heavy water" actually freezes at 3.8°C (39°F) rather than 0°C.
Thanks for a very interesting question! -Zach (+mbw)
(published on 12/28/2009)
Follow-up on this answer.