Outline of water

Faucet dripping water.

Structure of the water molecule (H₂O)

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, and runoff, 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

Seawater.

Boiling water.

• Water (molecule)
• Electrolysis of water
• Water of crystallization
• Dealkalization of water
• Drinking water quality standards
• Self-ionization of water
• Water-in-water emulsion
• Water purification
• Water (data page)
• Hard water / Soft water
  • Water softening
• Water absorption
• Heavy water
• Distilled water
• Salinity
  • Saline water
  • Seawater
• Hydrate
• Boiling

Physical properties

Frozen water, that is, ice.

• Water (properties)
  • Color of water
  • Water vapour
    • Vapour pressure of water
    • Steam
  • Ice
    • Lunar ice
  • Optical properties of water and ice
  • Water quality
  • Water (data page)
• Mineral water

Geography

The Water Cycle

Rapidly flowing river.

Formation of a Waterfall		Victoria Falls

• Origin of water on Earth
  • Evolution of water on Mars and Earth
• Hydrosphere
  • Hydrology
    • Water distribution on Earth
  • Water cycle
  • Groundwater
• Body of water
  • Ocean
  • Sea
    • Tide
  • Seawater
    • Saline water
    • Brine
    • Brackish water
  • River
    • Drainage
      • Drainage divide
      • Drainage basin
  • Lake
• Freshwater
• Glacier
• Waterfall
  • List of waterfalls

Weather

A snowflake.

Snow-covered trees.

• Precipitation (meteorology)
  • Rain
  • Freezing rain
  • Drizzle
  • Snow
  • Snow pellets
  • Snow grains
  • Ice pellets
  • Hail
  • Ice crystals
  • Dew
  • Hoarfrost
  • Atmospheric icing
  • Glaze ice
• Clouds
• Fog
• Mist
• Spindrift
• Flood
• Wave
  • Wind wave
  • Tsunami
• Drought

In nature and life

• Origin of water on Earth
  • Evolution of water on Mars and Earth
• Water intoxication
• Drinking water
• Drowning
• Dehydration

Marine life

• Underwater
• Marine biology
• Hydrobiology
  • Aquatic ecosystem

Politics and issues

• Water politics
  • Water politics in the Middle East
  • Water politics in the Jordan River basin
• Water law
• Water right
• Water resources
  • Water resources of the People's Republic of China
  • Water resources of Singapore
• Reuse of water bottles
• Water crisis
  • Water conservation
    • Water efficiency
    • Water footprint
• Water industry
  • Water privatization
  • Water management
• Water conflicts
• Water export
• Water pollution

Supply and sanitation

An example of a Reservoir, Ladybower Reservoir.

• Water supply
  • Water supply network
    • Reservoir
    • Dam
    • Water tower
    • Aqueduct
    • Pump
    • Water well
    • Drinking Fountain
    • Water pipe
      • Plumbing
    • Tap (valve)
• Sanitation
• Drinking water
• Water flouridation
  • Opposition to water fluoridation

In culture and sport

Poseidon, Greek god of water. The Roman water god, Neptune, was almost identical to Poseidon

• Water deity
• Water (classical element)
• Holy water
• Water sport (recreation)
  • List of water sports
    • Swimming
    • Water polo
• Winter sport
• Water gun
• Water fight
• Fountain

Uses

• Water wheel
• Hydropower
  • Water turbine
  • Steam engine
• Drinking
  • Drinking water
  • Tap water
  • Bottled water
  • Drinking vessel
    • Glass (drinkware)
• Water clock
• Irrigation
• Use of water in fire fighting
• Professional diving
• Water transport
• Bathing
  • Sink
  • Bathtub
  • Shower
• Washing
  • Pressure washer
• Naval warfare

Fishing

References

1. ^ United Nations
2. ^ "CIA- The world fact book". Central Intelligence Agency. https://www.cia.gov/library/publications/the-world-factbook/geos/xx.html#Geo. Retrieved 2008-12-20. 
3. ^ Water Vapor in the Climate System, Special Report, [AGU], December 1995 (linked 4/2007).Vital Water UNEP.
4. ^ 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. 
5. ^ "Charting Our Water Future: Economic frameworks to inform decision-making"

See also

• Hydrological Ensemble Prediction Experiment