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Teachers to Explore the Unique Properties of Water By Don Cloutman Biologists sometimes refer to water as the sine qua non of life. In plain English, that means that life cannot exist without water. Water is so important that it comprises over 70% of most organisms. Water has an interacting combination of four unique and two other properties that are needed for life to exist. Water is the only substance that has this unique combination of properties necessary for life. The Headwaters Science Center, through a grant from the Howard Hughes Medical Institute, will present a workshop during August 12-16 to area middle school teachers exploring methods of teaching their students these properties and their importance. Teachers interested in taking this workshop may contact the Headwaters Science Center at 444-4472. Teachers also have an option to take this workshop for credit from Bemidji State University. Here is just a tid-bit of what the teachers will be covering in the workshop and teaching to their students this next school year. Two important, but not unique, properties of water for life are that water is liquid at normal temperatures over much of the earth and that water is transparent. If water were not liquid, nutrients could not flow from soil to the roots of plants, blood could not circulate, and bodies of organisms would be so rigid that they could not move. If water were not transparent, light could not penetrate through cellular protoplasm into chloroplasts to drive photosynthesis in plants, you would be blind because light could not penetrate through the vitreous humor to the retina of your eyes, and light could not penetrate into lakes to allow growth of phytoplankton. Perhaps you can think of other reasons why life depends on the liquidity and transparency of water. Water is often called the universal solvent because it has the unique ability to dissolve more materials than just about any other substance. In our workshop, we will delve into the chemistry that allows water to dissolve so many things (Hint- it has to do with water being able to form three kinds of chemical bonds at the same time). Plants and animals are very complex beings with thousands of chemicals reacting in concert. Substances such as sugar, protein, fat, vitamins, salt, and oxygen would not be able to come together and react properly in cellular respiration if water were not the universal solvent. Water has another unique property called the density anomaly. Unlike most liquids, which are most dense at their freezing point, water is most dense at 40 degrees Fahrenheit and less dense at its freezing point (32 degrees Fahrenheit). If it were not for the density anomaly of water, lakes in northern Minnesota and other temperate and polar places would become solid from the bottom up during winter. There would be no water for aquatic organisms to swim in, and they would freeze. Another unique property of water is its high specific heat. This means that a body of water can gain or lose a lot of heat without changing the temperature very much.
Approximate Word count = 1983
Approximate Pages = 7.9
(250 words per page double spaced)
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