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Posted by Julian Taub | Dec 27, 2011

The Science of Snow

Science blogger Julian Taub makes living with snow and ice a little easier.

Morguefile.comWe all enjoy the winter wonderland that nature provides us with each winter. Well, except when it’s covering the driveway. Regardless of how serene and beautiful it looks, snow can be a pain to deal with, literally. Knowing a few facts about snow can help you deal effectively with this fluffy winter pest.

Snow is made out of dust particles that freeze in the clouds. When snow hits the ground, it is mostly made up of ice, air bubbles and water vapor.(1, 2) The density of the snow (how heavy it is) depends on how much water the snow contains altogether. The more “water content” in the snow, the harder it is to shovel. Old packed snow is the worst of them all; you can barely get your shovel into it.(3)

Despite the fact that snow is less dense than water, shoveling snow can be a major strain on the body. In cold weather, the body’s blood vessels constrict in order to hold onto whatever heat it can. However, the heart and lungs have to work even harder to pump oxygen to the lungs.(4, 5) Coupled with lifting pounds of snow every ten to thirty seconds, it is very easy to pull a muscle or become out of breath. It can even become life threatening to someone prone to heart attacks. Remember to always stretch beforehand, pace yourself, and use a shovel that matches your body type.(6)

Forget melting snow with a heater. It doesn’t work all that well and you can waste a lot of energy that way. Because of the air pockets within snow crystals, snow is a very good insulator. Heat doesn’t travel well through a snow mound.(7, 8, 9)  Moreover, when snow does melt during winter, a new problem arises. The leftover water from the melted snow usually turns into ice. The surface of ice has a microscopic layer of water that allows the ice to be slippery.(10) Also, the water molecules in the ice both bond tightly to each other when frozen and bond to the molecules of the ground below.(11) This makes it excruciatingly difficult to scrape off and remove.

The best mode of snow removal and ice removal is using a de-icer. They are usually made out of some kind of salt that is absorbed into the ice or snow. Water has a lower freezing point when something is dissolved in it, making sure the ice and water mixture melts and cannot freeze again. Three of the most used de-iceing chemicals are table salt (sodium chloride), calcium chloride, and magnesium chloride. Unlike table salt, the calcium and magnesium chlorides also give off heat when they mix with water, helping the melting process.(12)  However, salts can damage plant life, badly made concrete (concrete that has air bubbles in it) and metals, like steel and aluminum.(13, 14)  This is especially true with magnesium chloride, which can change the chemical makeup of concrete and harm electrical appliances.(15, 14) CMA, a chemical made of calcium, magnesium, and vinegar is a non-corrosive and safe alternative for de-icing. Still, as a precaution, check the quality of your concrete and rub alcohol around metal surfaces to lower the freezing point of the ice on them.(12, 16)

References:

1. Snow Science. SciLinks: from the National Science Teachers Association. 2009. Dec, 23,2011.

2. Maeno, N. et al. Metaphorism of Air Bubbles in a Snow Crystal. Institute of Low Temperature Science, Hokkaido, Sapporo, Japan. Journal of Glaciology. Vol. 6, No. 46, 1967.

3. Snow and Avalanche Glossary. Avalanche-center.org. 2011. Dec 23, 2011

4. Kaiser, Manfred. Cold Weather Effects on the Circulatory System. Knol Beta, 2009. Dec 23, 2011

5. Beer, Tom. Book Review: How the Weather Affects your Health by Manfred Kaiser. Australian Meteorological Magazine 51 (2002) pgs. 267-269

 

6. Smart and Safe Snow Removal. Bay State Health. Dec 7, 2011. Dec 23, 2011.

7. Basic Concepts: Thermal Conductivity. Alaska Lake Ice and Snow Observatory Network. Lake Ice and Snow Science. Dec 23, 2011.

8. Practical Snow Melt Design. Tesmar Application Technology. 1995. Dec 23, 2011.

9.      Frequently Asked Questions about Snow. All About Snow. National Snow and Ice Data Center. Nov 2002, Dec 23, 2011.

10.  Chang, Kenneth. Explaining Ice: The Answers Are Slippery. New York Times Science. Feb 21, 2006. Dec 23, 2011.

11.  Adhesion and Cohesion of Water. Water Science for Schools. US Geological Survey. Dec 22, 2011. Dec 23, 2011.

12. Winter De-icing Agents for the Homeowner. University of Nebraska-Lincoln Institute of Agricultural and Natural Resources. Feb 2007. Dec 23, 2011. 

13. Carter, Tim. Deicing Salt and Concrete. Ask the Builder. 1993-2011. Dec 23, 2011.

14. Magnesium Chloride as a Deicing Agent. United States Department of Agriculture Rural Utilities Service. Summary of Items of Engineering Interest, Oct 2001. Dec 23, 2011.

15. Magnesium Chloride on Roads. Montana Chapter, Northwest Truckers Cooperative. Feb 24, 2003. Dec 23, 2011.

16.  Isopropanol (2-Propanol) Based Water Solutions: Freezing and Flash Points. The Engineering Toolbox. Dec 23, 2011

Julian Taub is a Networx - http://www.networx.com - writer. Get home & garden ideas like this - http://www.networx.com/article/the-science-of-snow - on Networx.

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