Water Essay

Eric Chang

August 16, 09

IB1 BIO SL

Mrs. Sandercock

Water Essay

Water is the most abundant substance we have on earth and vital to all life forms. It is the very essence and the source of life thus no organisms can live without water. The unique arrangement of polar covalent bond in the atomic level of a water molecule causes the two ends of the molecules to have opposite charges. This allows water to demonstrates unique thermal, cohesive, and solvent properties that contributes to the necessity of water to life.

Thermal properties

Water possess thermal properties of high heat capacity and high heat of vaporization that are significant to life. Water has a very high heat capacity, thus it can absorb or lose much heat before its temperature changes greatly. Due to this property, water act as a temperature stabilizer in maintaining body heat in animals. Moreover, water has a high heat of vaporization, for this reason many animals use it as a cooling mechanism for it lowers your body temperature by taking heat from your body and evaporating the perspiration. It also takes a lot of energy before vaporization occurs. Thus water evaporates slowly from ponds and lakes, where many aquatic life forms are dependent on a stable, warm living environment.

Cohesive Properties

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Cohesive Properties

Water molecules are highly cohesive because of the slightly positive and negative ends the polar covalent bonds creates. The positive ends of the molecules attract to the negative ends of another whenever they are close to each other. This generates surface tension and it is why boats can float on water. Cohesive property is crucial to life because when water freezes , the polar attraction of the water molecule lock into place and ice forms. For this reason, ice is less dense than liquid water so that ice floats instead of sinking. This permits life to develop in polar regions where life continue living below the surface of floating ice. And when water molecules attract to other molecules besides water, it is termed adhesion. Adhesion is essential for plants to grow because water goes against gravity by moving along the vascular tissue in plants attracting to the polar ends of the molecules in the plant, delivering nutrients to the ends of the plants.

Solvent properties

Water is also an universal solvent due to its polarity. Most molecules found within or surrounding the most cells are polar molecules as well and because water is a good solvent for biochemical molecules, it is the medium where biochemical reactions occur. The solvent properties of water is important to life because water is an excellent medium to transport. As mentioned earlier, water carries dissolved nutrients and minerals from the soil up from the roots to the leaves of the plant. In addition, blood is primary composed of water and blood is the most common transport medium the regulates in our body by giving nutrients and taking out waste.

Summary Statement

Though how water provides all this unique properties are complex but there are no doubts that they are all meant for the benefits of all lives on earth. The fact that only water possess all these properties only emphasize the necessity and importance of water on earth.

Bibliography

Damon, Alan, Randy McGonegal, Patricia Tosto, and William Ward. Pearson Baccalaureate: Higher Level Biology for the IB Diploma (Pearson International Baccalaureate Diploma: International Editions). Chicago: Heinemann, 2008.

"Importance of Water | Our Environment." Our Environment | Promoting Environmental Sustainability. 15 Aug. 2009 <http://www.sawse.org/Training.html>.

"Water properties." USGS Georgia Water Science Center. 16 Aug. 2009 <http://ga.water.usgs.gov/edu/waterproperties.html>.