Plasticine, Salt, and Melting Snow

Salt water ice freezing

Why do they grit the roads with rock salt in winter? What does the salt do to the water to reduce ice on the roads? Is this somehow related to how salt affects the boiling point of water? Keywords to search for: colligative properties, boiling, freezing, ions, solutions, solvent, Raoult’s law

Meanwhile, I’ll let Plasticine models from Ithaca and cheesy music explain:

Incidentally, if it is too cold, no amount of salt will prevent the roads freezing, but if climate predictions are to be believed then that will not be a problem for much longer. (Unless the computer models are all wrong and we are heading for another ice age…now where did I put that hot-water bottle?)

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9 thoughts on “Plasticine, Salt, and Melting Snow

  1. Hi. I was looking for cancer related gene and protin of some such and end up in your blog.  I liked your articles about everyday science easyly explaind. 

    Good luck.

  2. Cristina, why couldn’t Facebook or MySpace be used as a teaching aid? Students are already highly active on sites such as those, why couldn’t a teacher set up a page or group with enticing, interesting stuff that engaged. News outlets, such as The Guardian, are very successfully engaging a previously disinterested public with their science podcast page on Facebook and other such efforts. I cannot quite picture what a teacher might include on a MySpace page, but gathering together great edutainment in the form of Youtube clips, as you mention, could be one way to begin.

    A whole standalone website requires all the attendant start-up and search engine optimisation to get it seen. Also, I think a proportion of student would find it quite amusing that a teacher was on MySpace, even if they scoffed initially, at least some of them might find it fun and potentially informative…you never know, it could just work.

    db

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