WATER AND ITS CHARACTERISTICS
Water is the only
substance on earth that is present in solid, liquid and gaseous
states. Water is composed of two atoms of hydrogen covalently
bonded to one atom of oxygen. Water is a wonderful social
molecule as it likes to hang out with all kinds of molecules.
Water sticks to itself and to other substances, basically a
friendly molecule. These properties allow water to rise high
through a plant from its roots through its stem to its leaves in
a process called transpiration. Ice has a lower density than
liquid water. Ice floats on water. Without it, life as we know it
would be impossible. Water dissolves minerals and nutrients in
soil and sediments. It can dissolve more substances than any
other substance--a universal solvent. Water has a high boiling
and low freezing point so it remains liquid in most climates on
earth. Because liquid water changes temperature very slowly, it
hold a lot of heat making it a very important coolant. Most of
the earth is made up of water, as are you--consisting mostly of
water-containing cells and tissues. It has been said that we live
on a water planet. Water plays a key role in shaping the earth's
surface, climate, and diluting pollutants.
Water is found in lakes, streams, oceans...surface water. It is
found in the form of atmospheric water vapor, snow / ice
(glaciers), and groundwater.
