Properties of Water

       Seventy percent of the earth’s surface is water.  Sixty percent of the human body is made up of water. Water is the only molecule that can exist in all three states: solid, liquid, and gas. Also, water has a covalent bond and is polar because the unequal sharing of unequal sharing of electrons. The oxygen (8 protons) attracts electrons more strongly than hydrogen (1 proton).

            Water has four properties that facilitate environments for life: cohesive behavior, ability to moderate temperature, expansion upon freezing, and versatility as a solvent. Cohesion is the ability for water molecules to bond and adhesion is the ability for those molecules to stick to other objects. An example of water’s cohesive behavior is in trees. The water molecules first stick to each other through cohesion, and then the water molecules stick to the xylem (tubes inside trees to transfer water up). After adhesion the molecules move up the tree and go up to the leaves and evaporate through transpiration.



            One of the four properties of water is the ability of water to moderate temperature.  Water takes thirty times longer to heat up than gold because the water absorbs energy and releases energy through creating and breaking bonds. That characteristic explains how ocean temperatures fluctuate much less than air temperatures on land. Also, the ability for water to moderate temperatures explains why coastal areas have milder climates than adjacent inland areas.

            Another property of water is its ability to expand upon freezing. When water freezes the molecules become more stable and form a crystalline pattern, creating more space and less mass. In addition, water at thirty two degrees Celsius has no molecular motion. An example of this property is when ice floats on water. Water’s ability to expand upon freezing helps keep water under the surface of large bodies of water, warmer and suitable for life.

            The fourth property of water is its versatility as a solvent. Water is an effective solvent because it readily forms hydrogen bonds. Water is also known as the universal solvent because it can dissolve many things. Also, water is a polar solvent so it can dissolve polar solutes.  But water cannot dissolve strong polar solutes like oil.

            In conclusion, water is the substance of life that is why scientists look for water on distance planets as an indication of possible existence of life.