Water

This article is about general aspects of water. For a detailed discussion of its properties, see water (properties). For other uses, see Water (disambiguation).

Water is the ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life.^[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface^[2]. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation.^[3] Oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products.

source: http://en.wikipedia.org/wiki/Water