Jan 8, 2008
Plasticine, Salt, and Melting Snow
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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When you say; “…that is how all this new technology (MySpace, Youtube, Facebook etc) might best be used to engage students more effectively than conventional teaching methods”. Do you mean that maybe these websites should be used to engage students in learning or be used as new teaching methods? I think it is too late to change the way Myspace or Facebook is being used by teenagers, but the idea to form a website that is designed to teach children in different ways that are not taught at school is very interesting. For instance, that youtube video did explain things very well.
Cristina, although perhaps you’re being a little flippant in the hope that your teacher might use clay models, you do actually hit on an important point about which educators and educational reformers should be thinking seriously and that is how all this new technology (MySpace, Youtube, Facebook etc) might best be used to engage students more effectively than conventional teaching methods.
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I thought the video was actually informing. While our AP. Chemistry class continues to bore me, yahoo chemistry videos entertain me. haha. Very funny. Maybe if our teacher would make clay figures to show us chemistry, then I can actually stay awake during class. haha.
Nice find Robert. The key, of course, is that sugar is soluble in water too, Raoult’s law applies equally well regardless of the solute and despite the sheep.
I managed to overcome my slackerism and tracked down this link:
http://pubs.acs.org/cen/newscripts/85/8509newscripts.html
It’s about a sugar based road grit that’s got sheep in Wales wandering the streets licking up the treats.