Water is an
inorganic,
transparent,
tasteless,
odorless, and
nearly colorless chemical substance, which is the main constituent of
Earth's
hydrosphere and the
fluids of most living
organisms. It is vital for all known forms of
life, even though it provides no
calories or
organic nutrients. Its
chemical formula is H2O, meaning that each of its
molecules contains one
oxygen and two
hydrogen atoms, connected by
covalent bonds. Water is the name of the liquid state of H2O at
standard ambient temperature and pressure. It forms
precipitation in the form of
rain and
aerosols in the form of
fog.
Clouds are formed from suspended droplets of water and
ice, its solid state. When finely divided, crystalline
ice may precipitate in the form of
snow. The gaseous state of water is
steam or
water vapor. Water moves continually through the
water cycle of
evaporation,
transpiration (
evapotranspiration),
condensation,
precipitation, and
runoff, usually reaching the sea.
