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Water is a fundamental and essential substance for life on Earth, covering approximately 71% of the planet’s surface. It is a unique compound composed of two hydrogen atoms bonded to one oxygen atom, forming the familiar H2O molecule. This simple yet powerful structure gives water its remarkable properties that are crucial for sustaining life and supporting various ecosystems.

Importance of Water

Water plays a vital role in numerous aspects of life, from supporting biological functions in organisms to shaping landscapes through erosion and deposition processes. It is essential for hydration, nutrient transport, temperature regulation, and waste removal in living organisms. Additionally, water serves as a solvent for many substances, facilitating chemical reactions and metabolic processes necessary for life.

Properties of Water

One of the most remarkable properties of water is its high specific heat capacity, which allows it to absorb and release large amounts of heat without significant temperature changes. This property is crucial for regulating Earth’s climate and maintaining stable temperatures in aquatic environments. Water also exhibits cohesion and adhesion, enabling it to form droplets, capillary action in plants, and surface tension on bodies of water.

Forms of Water

Water exists in various forms across the planet, including liquid, solid (ice), and gas (water vapor). The water cycle describes the continuous movement of water between these forms through processes such as evaporation, condensation, precipitation, and runoff. This cycle plays a critical role in distributing water resources around the globe and sustaining ecosystems.

Human Impact on Water

Human activities have significantly impacted water quality and availability worldwide. Pollution from industrial waste, agricultural runoff, plastic debris, and other sources has contaminated freshwater sources and marine environments, posing risks to human health and ecosystem stability. Over-extraction of groundwater for agriculture and urban development has led to depletion of aquifers and subsidence in some regions.

Sustainable Water Management

To ensure the availability of clean water for current and future generations, sustainable water management practices are essential. This includes conservation efforts to reduce water waste, implementing efficient irrigation techniques in agriculture, investing in wastewater treatment facilities to recycle water resources, and promoting awareness about the importance of preserving water quality.


In conclusion, water is a precious resource that sustains life on Earth in countless ways. Its unique properties and global distribution make it indispensable for ecosystems, human societies, and the planet as a whole. By understanding the significance of water, practicing responsible stewardship, and implementing sustainable management strategies, we can protect this vital resource for generations to come.

  1. https://en.wikipedia.org/wiki/Water – Water – This page provides an overview of water, including its chemical and physical properties, aquaphobia, human right to water and sanitation, hydroelectricity, and marine current power.
  2. https://en.wikipedia.org/wiki/Water_content – Water content – This page explains the concept of water content or moisture content, which is the quantity of water contained in a material such as soil, rock, ceramics, crops, or wood. It also describes the four standard water contents that are routinely measured and used.
  3. https://en.wikipedia.org/wiki/Water_resources – Water resources – This page explains water resources as natural resources of water that are potentially useful for humans, for example as a source of drinking water supply or irrigation water. It also provides a list of related topics such as water resources law, water rights, and virtual water.
  4. https://en.wikipedia.org/wiki/Properties_of_water – Properties of water – This page provides information on the properties of water, including its chemical formula, structure, and reactions. It also explains the anomalous properties of water, such as its high surface tension, boiling point, and heat capacity.
Merriam-Webster Online Dictionary
water (noun)
a) the liquid that descends from the clouds as rain, forms streams, lakes, and seas, and is a major constituent of all living matter and that when pure is an odorless, tasteless, very slightly compressible liquid oxide of hydrogen HO which appears bluish in thick layers, freezes at 0° C and boils at 100° C, has a maximum density at 4° C and a high specific heat, is feebly ionized to hydrogen and hydroxyl ions, and is a poor conductor of electricity and a good solvent - 2
b) a natural mineral water - usually used in plural
a particular quantity or body of water as
a) (1) the water occupying or flowing in a particular bed
(2) chiefly British - lake pond
b) a quantity or depth of water adequate for some purpose (as navigation)
(1) a band of seawater abutting on the land of a particular sovereignty and under the control of that sovereignty
(2) the sea of a particular part of the earth
d) - water supply threatened to turn off the water
travel or transportation on water - we went by water
the level of water at a particular state of the tide - tide
liquid containing or resembling water as
a) (1) a pharmaceutical or cosmetic preparation made with water
(2) a solution of a gaseous or readily volatile substance - watery compare ammonia water
b) archaic a distilled fluid (as an essence) , especially a distilled alcoholic liquor
c) a watery fluid (as tears, urine, or sap) formed or circulating in a living body
d) - amniotic fluid , also - bag of waters
a) the degree of clarity and luster of a precious stone
b) degree of excellence - a scholar of the first water
- watercolor
a) stock not representing assets of the issuing company and not backed by earning power
b) fictitious or exaggerated asset entries that give a stock an unrealistic book value
water (verb)
transitive verb
to moisten, sprinkle, or soak with water - water the lawn
to supply with water for drink - water cattle
to supply water to - lands watered by the river
to treat with or as if with water , specifically to impart a lustrous appearance and wavy pattern to (cloth) by calendering
a) to dilute by the addition of water - often used with down water down the punch
intransitive verb
b) to add to the aggregate par value of (securities) without a corresponding addition to the assets represented by the securities
to form or secrete water or matter (as tears or saliva) - watery
to get or take water as
a) to take on a supply of water - the boat docked to water
b) to drink water
Merriam-Webster Online Thesaurus
water (verb)
to make wet
bathe, bedraggle, douse ( dowse), drench, drown, soak, sodden, sop, souse, wash, water, waterlog, water-soak, wet down
asperse, bedew, damp, dampen, drizzle, humidify, hydrate, mist, moisten, moisturize, shower, sprinkle; deluge, flood, hose (down), inundate, overflow; submerge, swamp; splash; impregnate, saturate, steep; flush, irrigate, lave, rinse, slosh, sluice; dip, duck, dunk; rehydrate, rewash, rewet
dewater, evaporate, freeze-dry; drip-dry, wring; dehumidify
dehydrate, desiccate, dry, parch, scorch, sear
Water (Wikipedia)

Water is an inorganic compound with the chemical formulaH2O. 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°. "Water" is also the name of the liquid state ofH2O at standard temperature and pressure.

The water molecule has this basic geometric structure
Ball-and-stick model of a water molecule
Ball-and-stick model of a water molecule
Space filling model of a water molecule
Space filling model of a water molecule
  Oxygen, O
  Hydrogen, H
A drop of water falling towards water in a glass
IUPAC name
Systematic IUPAC name
Other names
  • Hydrogen oxide
  • Hydrogen hydroxide (HH or HOH)
  • Hydroxylic acid
  • Dihydrogen monoxide (DHMO) (parody name)
  • Dihydrogen oxide
  • Hydric acid
  • Hydrohydroxic acid
  • Hydroxic acid
  • Hydroxoic acid
  • Hydrol
  • μ-Oxidodihydrogen
  • κ1-Hydroxylhydrogen(0)
  • Neutral liquid
3D model (JSmol)
ECHA InfoCard100.028.902 Edit this at Wikidata
EC Number
  • 231-791-2
RTECS number
  • ZC0110000
  • InChI=1S/H2O/h1H2 checkY
Molar mass18.01528(33) g/mol
AppearanceAlmost colorless or white crystalline solid, almost colorless liquid, with a hint of blue, colorless gas
  • Liquid (1 atm, VSMOW):
  • 0.99984283(84) g/mL at 0 °C
  • 0.99997495(84) g/mL at 3.983035(670) °C (temperature of maximum density, often 4 °C)
  • 0.99704702(83) g/mL at 25 °C
  • 0.96188791(96) g/mL at 95 °C
  • Solid:
  • 0.9167 g/mL at 0 °C
Melting point0.00 °C (32.00 °F; 273.15 K)
Boiling point99.98 °C (211.96 °F; 373.13 K)
SolubilityPoorly soluble in haloalkanes, aliphatic and aromatic hydrocarbons, ethers. Improved solubility in carboxylates, alcohols, ketones, amines. Miscible with methanol, ethanol, propanol, isopropanol, acetone, glycerol, 1,4-dioxane, tetrahydrofuran, sulfolane, acetaldehyde, dimethylformamide, dimethoxyethane, dimethyl sulfoxide, acetonitrile. Partially miscible with diethyl ether, methyl ethyl ketone, dichloromethane, ethyl acetate, bromine.
Vapor pressure3.1690 kilopascals or 0.031276 atm at 25 °C
Acidity (pKa)13.995
Basicity (pKb)13.995
Conjugate acidHydronium H3O+ (pKa = 0)
Conjugate baseHydroxide OH (pKb = 0)
Thermal conductivity0.6065 W/(m·K)
1.3330 (20 °C)
Viscosity0.890 mPa·s (0.890 cP)
1.8546 D
75.385 ± 0.05 J/(mol·K)
69.95 ± 0.03 J/(mol·K)
−285.83 ± 0.04 kJ/mol
−237.24 kJ/mol
Occupational safety and health (OHS/OSH):
Main hazards
Avalanche (as snow)
Water intoxication
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Flash pointNon-flammable
Safety data sheet (SDS)SDS
Related compounds
Other cations
Related solvents
Supplementary data page
Water (data page)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

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.

Water plays an important role in the world economy. Approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies has been, and continues to be, a major source of food for many parts of the world, providing 6.5% of global protein. Much of the long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating in industry and homes. Water is an excellent solvent for a wide variety of substances, both mineral and organic; as such, it is widely used in industrial processes and in cooking and washing. Water, ice, and snow are also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating, snowboarding, and skiing.

Water (Wiktionary)





  • (United Kingdom)
    • (Received Pronunciation) IPA(key): /ˈwɔːtə/
    • (England, Estuary English) IPA(key): [ˈwoːʔɐ], [ˈwoːʔə]
    • (England, Cockney) IPA(key): [ˈwoʊʔə], [ˈwɔoɾɐ]
    • (Northern English, dated, obsolete elsewhere) IPA(key): /ˈwætəɹ/, [ˈwatə], [ˈwaɾɚ]
    • (Scotland) IPA(key): /ˈwɔtər/, [ˈwɔtər]
    • (dialectal) IPA(key): /ˈwɒtə/, /ˈwɒtəɹ/
  • (North America)
    • (General American) IPA(key): /ˈwɔtəɹ/, [ˈwɔɾɚ], enPR: wôtər
      • (US, cotcaught merger, Canada) IPA(key): /ˈwɑtəɹ/, [ˈwɑɾɚ], enPR: wŏtər
        • (NYC) IPA(key): [ˈwɔəɾə]
        • (Philadelphia) IPA(key): /ˈwʊtəɹ/, [ˈwʊɾɚ]
        • (Western Pennsylvania) IPA(key): /ˈwɔɹtəɹ/, [ˈwɔɹɾɚ]
      • (General Australian, New Zealand) IPA(key): /ˈwoːtə/, [ˈwoːɾə]
      • (Ireland) IPA(key): /ˈwɔːtəɹ/, [ˈwɒːθ̠ɚ]
      • (Indian English) IPA(key): [ˈwɔʈə(r)], [ˈʋɔʈə(r)]
        • (Tamil English) IPA(key): [ˈʋaːʈər(ɯ)], [ˈwaːʈər(ɯ)]
      • (General South African) IPA(key): [ˈwoːtə]
      • Hyphenation: wa‧ter
      • Rhymes: -ɔːtə(ɹ)

      Etymology 1

      From Middle English water, from Old English wæter (water), from Proto-West Germanic *watar, from Proto-Germanic *watōr (water), from Proto-Indo-European *wódr̥ (water).

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