H20 ...

on this planet, water is continuously moving through the cycle from one form to another. all known forms of life depend on water. the coexistence of the solid, liquid, and gaseous phases of water on earth is vital to the origin, evolution, and continued existence of life on earth.

water plays an atmospheric role as an absorber of infrared radiation, crucial in the atmospheric greenhouse effect. without it the average surface temperature would be −18° celsius.

H2O, two atoms of hydrogen and one of oxygen in every molecule, created civilizations such as mesopotamia, the so-called cradle of civilization, situated between two major rivers.

about 72% of the fat free mass of the human body is made of water. excess intake than necessary leads to water intoxication, which is frequently fatal.

liquid water contracts when cooled until it reaches a temperature of about 4° celsius, where it reaches its maximum density. when this temperature is reached liquid water begins to expand, and even with a change in state to ice, water continues to expand by reducing its density as its temperature decreases, it should be noted that almost all other chemicals are denser as solids than they are as liquids, and freeze from the bottom up. ice in a body of water will form first at the surface and progress downward.

the amount of heat it would take to melt a kilogram of ice, and boil away is 720 calories, which would be enough to raise the same amount of aluminum to its melting point !

water molecules have a unique ability to be energized by microwave radiation, and at the same time make an excellent barrier to nuclear radiation. it absorbs neutrons in nuclear powerplants, yet is easily heated by microwaves. water is the primary source of the raw materials needed for hydrogen bombs.

also because of water, we have water beds and waterbed theory, which is the observation that systems, such as human and computer languages, contain a minimum amount of complexity, and that attempting to "push down" the complexity of such a system in one place will invariably cause complexity to "pop up" elsewhere ...