Water is a chemical substance, composed of hydrogen and oxygen, vital for all known forms of life.[1] In typical usage, water refers only to its liquid state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Covering 71% of the Earth's surface,[2] 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, and precipitation.[3]
Water on Earth moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, andrunoff, usually reaching the sea. Over land, evaporation and transpiration contribute to the precipitation over land.
Clean, fresh drinking water is essential to human and other lifeforms. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability.[4] A recent report (November 2009) suggests that by 2030, in some developing regions of the world, water demand will exceed supply by 50%.[5]
This outline is provided as an overview of and topical guide to water:
Chemical properties and use[edit | edit source]
- Water (molecule)
- Electrolysis of water
- Water of crystallization
- Dealkalization of water
- Self-ionization of water
- Water-in-water emulsion
- Water purification
- Water (data page)
- Hard Water / Soft Water
- Water absorption
- Heavy water
- Distilled water
- Salinity
- Hydrate
- Boiling
Physical properties[edit | edit source]
Geography[edit | edit source]
Weather[edit | edit source]
In nature and life[edit | edit source]
Marine life[edit | edit source]
Politics and issues[edit | edit source]
- Water politics
- Water law
- Water right
- Water resources
- Reuse of water bottles
- Water crisis
- Water industry
- Water conflicts
- Water export
- Water pollution
Supply and sanitation[edit | edit source]
In culture and sport[edit | edit source]
- Water deity
- Water (classical element)
- Holy water
- Water sport (recreation)
- Winter sport
- Water gun
- Water fight
- Fountain
Uses[edit | edit source]
- Water wheel
- Hydropower
- Drinking
- Water clock
- Irrigation
- Use of water in fire fighting
- Professional diving
- Water transport
- Bathing
- Washing
- Naval warfare
Fishing[edit | edit source]
References[edit | edit source]
- ↑ United Nations
- ↑ "CIA- The world fact book". Central Intelligence Agency. Retrieved 2008-12-20.
- ↑ Water Vapor in the Climate System, Special Report, [AGU], December 1995 (linked 4/2007).Vital Water UNEP.
- ↑ Kulshreshtha, S.N (1998). "A Global Outlook for Water Resources to the Year 2025". Water Resources Management 12 (3): 167–184. doi:10.1023/A:1007957229865.
- ↑ "Charting Our Water Future: Economic frameworks to inform decision-making"