Pure water is without color, flavor and odor. Freezing point of water, i.e. temperature on which water becomes ice, is 0 oC, and boiling point, i.e. temperature on which water becomes vapor, is 100 oC. Density of water is 100 kg/l. This is a large size density for the liquid - i.e. the water is relatively hard and this value is taken as the standard for determining density of other substances.
The water is one of the basic elements of ecosystems, natural occurrences of regions and continents. In a firm way, water is connected to all forms of life on the Earth, so the importance of water steerage is one of the primary life decisions, as activities all actor of civilization. As for the substance, living organisms do not only need water presence, but also water storage. A human body consists of 70 % of water, while the body of mollusks, like Jelly Fish, has more than 98 % of this liquid. For a man, water represents a source of life and humour. Without water, the man is able to survive from 3 to 5 days.
|Molar mass||18,0153 g/mola|
|Viscosity||0,001 Pa m (on 20° C)|
|Density||1.000 kg/m3 –liquid;|
917 kg/m3 – ice;
|Triple point||273,16 K, 599,844 Pa|
|Surface tension (on 20° C)||7,275 N/m|
|Refractive index, nb||1,333 (on 20° C)|
|Relative static permittivity||80,2 (on 20° C)|
Water is formed from 11,11 % of Hydrogen and 88,88 % of Oxygen. Molecule of water forms crystalline in the tetrahedral configuration. A droplet of water with the size of a pinhead, includes miliard-miliards molecules. They are closely connected, especially on the water surface, where their connection produces powerful epitaxial stress, popular as tension.
Water character easily changes its own condition, and it easily expands, enabling water to be always in movement and to circle in a global and local cycle.
Throughout the history, water was a determinant element of the survival of civilizations, like Egypt, Mesopotamia, Inca...
Development of human population and large industrial expansion demand the increase of water supply and its distribution. Users sluice a large volume of water, more or less polluted, in natural environment and in this way cause the decrease of water quality and derange the function of aquatic system.