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Introduction: Water is an inorganic compound with the chemical formula H2O. It is a transparent, tasteless, odorless, and nearly colorless chemical substance, and it is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food energy or organic micronutrients. Its chemical formula, H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. In liquid form, H2O is also called "Water" at standard temperature and pressure. Because Earth's environment is relatively close to water's triple point, water exists on Earth as a solid, a liquid, and a gas. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of 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 covers about 71% of the Earth's surface, with seas and oceans making up most of the water volume (about 96.5%). Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor, clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.

Etymology: The word water comes from Old English wæter, from Proto-Germanic *watar (source also of Old Saxon watar, Old Frisian wetir, Dutch water, Old High German wazzar, German Wasser, vatn, Gothic 𐍅𐌰𐍄𐍉 (wato)), from Proto-Indo-European *wod-or, suffixed form of root *wed- ('water'; 'wet').

On earth: Hydrology is the study of the movement, distribution, and quality of water throughout the Earth. The study of the distribution of water is hydrography. The study of the distribution and movement of groundwater is hydrogeology, of glaciers is glaciology, of inland waters is limnology and distribution of oceans is oceanography. Ecological processes with hydrology are in the focus of ecohydrology. The collective mass of water found on, under, and over the surface of a planet is called the hydrosphere. Earth's approximate water volume (the total water supply of the world) is 1.386 billion cubic kilometres (333 million cubic miles).

Water cycle: Water moves perpetually through each of these regions in the water cycle consisting of the following transfer processes:

evaporation from oceans and other water bodies into the air and transpiration from land plants and animals into the air.

precipitation, from water vapor condensing from the air and falling to the earth or ocean.

runoff from the land usually reaching the sea.

Auquatic life forms: The sea, once it casts its spell, holds one in its net of wonder forever. - Jacques Cousteau

Earth's surface waters are filled with life. The earliest life forms appeared in water; nearly all fish live exclusively in water, and there are many types of marine mammals, such as dolphins and whales. Some kinds of animals, such as amphibians, spend portions of their lives in water and portions on land. Plants such as kelp and algae grow in the water and are the basis for some underwater ecosystems. Plankton is generally the foundation of the ocean food chain.

Poetry: Water appears as one of the leading symbols in oral and written literature since the beginning of history. As a must-have life source, water penetrates into literary works with a variety of symbolism.

Into the sunshine,  Full of the light, Leaping and flashing,  From morn till night! Into the moonlight, Whiter than snow, Waving so flower-like When the winds blow! Into the starlight, Rushing in spray, Happy at midnight,  Happy by day! by James Russell Lowell (1819-1891)

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Water
Names
IUPAC name Water
Systematic IUPAC name Oxidane
Other names Hydrogen oxide Hydrogen hydroxide (HH or HOH) Dihydrogen oxide Hydric acid μ-Oxidodihydrogen κ1-Hydroxylhydrogen(0) Aqua

Properties

Chemical formula: H2O

Molar mass: 18.01528(33) g/mol

Appearance: Almost colorless or white crystalline solid, almost colorless liquid, colorless gas

Water bottles

Single use plastic:

pros: light-weight, affordable, variety, dishwasher-safe

cons: plastic waste, harmful chemicals, retain oders over time, limited insulation

Stainless steel:

pros: durable temperature retention, no harmful chemicals, reusable

cons: heavy, expensive, opaque

Glass:

pros: purity (non-porous), reyclable, aesthetics, no harmful chemicals

cons: fragile, can cause injuries, bad insulation, heavy