Thursday, October 24, 2019

Some Unusual Properties of Water Essay -- Geology

Some Unusual Properties of Water Cohesion/Adhesion Water molecules attract each other as a result of hydrogen bonding. This ionic attraction is 1/20 as strong as covalent bond in water's liquid form. They form, break and re-form with great frequency; each hydrogen bond last only a few trillionths of a second, but the molecules bond promiscuously to a succession of partners. At any instant, a substantial percentage of all the water molecules are bonded to their neighbors, giving water more structure than other liquids. Collectively, this phenomenon is known as cohesion. A related property of cohesion is adhesion, a water molecule's attraction to other polar surfaces. This is, again, directly attributed to water's high polarity. Hydrophilic substances/materials, having similar strong polarity, are attracted to water through polar interactions. If you have ever tried to separate two glass slides stuck together with a film of water, you can appreciate how tightly water adheres to glass, a hydrophilic substance. (Water Module) Biological Impact: Water's cohesive property is especially crucial to the survival of plants. Cohesion due to hydrogen bonding contributes to the transport of water against gravity in plant xylem. As transpiration, water evaporation, in leaves occurs, water in the plant xylem is "tugged" into the leaves to replace evaporated water. This upward pull is transmitted along the vessel all the way to the roots. This cohesive property allows tall evergreen trees to survive. Water cohesion also leads to another property known as surface tension, a measurement of the strength and toughness of the surface of a liquid to penetration. Because of water's high surface tension, due to hydrogen bonding, insects such ... ... bonded to a maximum of four partners. In this structure, the hydrogen bonds distance the molecules so that ice is 10% less dense than liquid water. Biological Impact: The expansion of water as it solidifies is especially important to the fitness of the environment. Ice's natural tendency to float prevents the freezing of lakes, ponds and even oceans during winter, allowing organisms within these ecosystems to survive. Further, because ice floats, it is able to prevent the loss of heat from bodies of water, providing insulation for aquatic organisms. The freezing of water and melting of ice also ease the transition between seasons for organisms. When water solidifies into ice or snow, the heat released warms the surrounding air, helping to temper the autumn. Similarly, during the spring, melting ice absorbs heat, tempering the transition into the warmer season.

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