Water
hideWater is a ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, 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 (formed of solid and liquid water particles suspended in air), and precipitation. Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Other water is trapped in ice caps, glaciers, aquifers, or in lakes, sometimes providing fresh water for life on land.
Water moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea. Over land, evaporation and transpiration contribute to the precipitation over land.
Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70 percent of freshwater is consumed by agriculture.
For more information about Water, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with water
Invading camels to be shot in Australian town
13 hours ago |
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(AP) -- Australian authorities plan to corral about 6,000 wild camels with helicopters and gun them down after they overran a small Outback town in search of water, trampling fences, smashing tanks and contaminating ...
Fast, easy, and highly sensitive arsenic detection with gold nanoparticles
Nanotechnology / Nanomaterials
Nov 25, 2009 |
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(PhysOrg.com) -- Mention of arsenic poisoning usually brings to mind underhanded murder. However, the danger of arsenic poisoning from contaminated drinking water is far greater. Low concentrations of arsenic are found in ...
Asian carp may have breached barrier protecting Lake Michigan
Nov 24, 2009 |
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Two feared species of Asian carp have zoomed beyond the $9 million electric barriers built to keep them out of Lake Michigan. Now, the only thing left between the carp and the Great Lakes is a lock and dam in southern Chicago.
Dehydration Affects Mood, Not Just Motor Skills
Nov 24, 2009 |
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(PhysOrg.com) -- Dehydration has long been known to compromise physical performance. Now, a new study provides insight into the effects of mild dehydration on young athletes, and possibly into the lives of ...
Dead Sea needs world help to stay alive
Nov 24, 2009 |
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The Dead Sea may soon shrink to a lifeless pond as Middle East political strife blocks vital measures needed to halt the decay of the world's lowest and saltiest body of water, experts say.
Cassini Sends Back Images of Enceladus as Winter Nears
Space & Earth / Space Exploration
Nov 23, 2009 |
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(PhysOrg.com) -- NASA's Cassini spacecraft has sailed seamlessly through the Nov. 21 flyby of Saturn's moon Enceladus and started transmitting uncalibrated temperature data and images of the rippling terrain. ...
3 Questions: Sara Seager on searching for Earth-like planets
Nov 23, 2009 |
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(PhysOrg.com) -- MIT planetary scientist Sara Seager has been studying exoplanets — planets circling stars other than the sun — for many years.
Time-Tunneling for Climate Change Clues
Nov 23, 2009 |
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(PhysOrg.com) -- If you look closely at individual plant species' responses in the past, you may find that the largest effects of high carbon dioxide (CO2) levels occurred decades ago, according to Agricultural ...
Robotic clam digs in mudflats
Nov 22, 2009 |
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To design a lightweight anchor that can dig itself in to hold small underwater submersibles, Anette (Peko) Hosoi of MIT borrowed techniques from one of nature's best diggers -- the razor clam.
El Nino intensifies Latin America drought
Space & Earth / Earth Sciences
Nov 20, 2009 |
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From a devastating food crisis in Guatemala to water cuts in Venezuela, El Nino has compounded drought damage across Latin America this year.
SMOS satellite instrument comes alive (w/ Video)
Space & Earth / Space Exploration
Nov 19, 2009 |
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The MIRAS instrument on ESA's SMOS satellite, launched earlier this month, has been switched on and is operating normally. MIRAS will map soil moisture and ocean salinity to improve our understanding of the ...
Boosting the amount of energy obtained from water
Nov 18, 2009 |
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The energy generated in places where fresh water and salt water meet is known as blue energy. This is a relatively new but highly promising renewable energy source. Piotr Długołęcki of the University ...
Sharks under threat as environmental change bites hard
Nov 17, 2009 |
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(PhysOrg.com) -- Their size and fearsome appearance have made them the stuff of nightmares, but new research just published suggests that sharks may not be as tough as they appear.
Study: Sea stars bulk up to beat the heat
Nov 17, 2009 |
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A new study finds that a species of sea star stays cool using a strategy never before seen in the animal kingdom. The sea stars soak up cold sea water into their bodies during high tide as buffer against potentially damaging ...
Japanese researchers film rare baby fish 'fossil'
Nov 17, 2009 |
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Japanese marine researchers said Tuesday they had found and successfully filmed a young coelacanth -- a rare type of fish known as "a living fossil" -- in deep water off Indonesia.
