At dinner tonight, an interesting debate arose about the use of salt on icy roads. While it was my opinion that the salt simply absorbs the ice as it melts naturally into water, leaving 'dry' ice, Erik felt that he'd heard from a very reliable source that the salt actually lowers the melting point of ice, thereby melting the ice more quickly and absorbing the water.
I suppose that this could be concievable, but I think it would require that the salt either actually change the chemical characteristics of the ice, or that the salt would have some internal energy not normally found in other substances that would be transferred to the ice in the form of heat. Both are concievable, but it seems to me that the second idea is the most likely.
On a related note, I discovered today just how deep the roots of the geek tree run in my group of friends . . .
Addendum from MarkyB, 12-1
I would have to agree with Erik, and confirm that the reliable source that he heard this from was none other than Tom Roland himself (probably one of the top five professors in Thompson hall). If my memory serves correct, salt mixed with water creates an endothermic reaction whereby heat is transfered to the ice causing it to melt. If you add salt to water and stir it, there is a noticeable increase in the temp of the water. Ever wonder why the polar ice caps are made of fresh water? Oh yeah, the geek tree roots just got deeper.
http://www.howstuffworks.com/question58.htm
Posted by: Shane at November 24, 2003 10:45 PM