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 liquid water
Rare Scottish mineral may indicate life on Mars
Space & Earth / Space Exploration
16 hours ago |
3.5 / 5 (19) |
6
(PhysOrg.com) -- A team of NASA (National Aeronautics and Space Administration) scientists is looking for clues about life on Mars in an earthy clay mineral found only in Aberdeenshire in Scotland.
Why Does Water Expand When it Cools? A New Explanation
Jul 17, 2009 |
4.2 / 5 (39) |
16
(PhysOrg.com) -- Most of us, when we take our first science classes, learn that when things cool down, they shrink. (When they heat up, we learn, they usually expand.) However, water seems to be the exception ...
Jupiter's Moon Europa Has Enough Oxygen For Life
Space & Earth / Earth Sciences
Oct 16, 2009 |
4.8 / 5 (97) |
42
New research suggests that there is plenty of oxygen available in the subsurface ocean of Europa to support oxygen-based metabolic processes for life similar to that on Earth. In fact, there may be enough ...
A Tale of Planetary Woe (w/ Video)
Space & Earth / Space Exploration
Nov 11, 2009 |
4.2 / 5 (11) |
5
Once upon a time — roughly four billion years ago — Mars was warm and wet, much like Earth. Liquid water flowed on the Martian surface in long rivers that emptied into shallow seas. A thick atmosphere blanketed ...
Will Kepler find habitable moons?
Sep 03, 2009 |
5 / 5 (14) |
5
(PhysOrg.com) -- Since the launch of the NASA Kepler Mission earlier this year, astronomers have been keenly awaiting the first detection of an Earth-like planet around another star. Now, in an echo of science ...
Scientists Observe Liquid Water Below Freezing
Jun 24, 2009 |
4.2 / 5 (14) |
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(PhysOrg.com) -- Below 0 °C, water turns to ice. But beyond that, or below about -75 °C, the ice may turn back into liquid water. While scientists have previously predicted this phase transition with computer ...
3 Questions: Sara Seager on searching for Earth-like planets
Nov 23, 2009 |
3.3 / 5 (3) |
0
(PhysOrg.com) -- MIT planetary scientist Sara Seager has been studying exoplanets — planets circling stars other than the sun — for many years.
Liquid saltwater is likely present on Mars, new analysis shows
Space & Earth / Space Exploration
Mar 17, 2009 |
4.7 / 5 (18) |
6
(PhysOrg.com) -- Salty, liquid water has been detected on a leg of the Mars Phoenix Lander and therefore could be present at other locations on the planet, according to analysis by a group of mission scientists ...
Scientists Develop New Method to Find Alien Oceans, Earth-like Planets (w/Videos)
May 26, 2009 |
4.9 / 5 (14) |
3
(PhysOrg.com) -- Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Powerful space telescopes, such as the ...
Taking a Bite of Antarctic Ice
Space & Earth / Space Exploration
Nov 16, 2009 |
3.8 / 5 (6) |
1
Scientists with NASA’s IceBite project are heading this week for University Valley, a hanging valley perched more than 1600 feet (more than 1 mile) above sea level in Antarctica’s McMurdo Dry Valleys. Their ...
It's a grind to make Mars red
Space & Earth / Space Exploration
Sep 18, 2009 |
4.6 / 5 (5) |
2
(PhysOrg.com) -- The widespread idea that Mars is red due to rocks being rusted by the water that once flooded the red planet may be wrong. Recent laboratory studies show that the red dust may be formed by ...
Kepler and the Search for Life in Our Galaxy
Sep 15, 2009 |
4.3 / 5 (9) |
1
(PhysOrg.com) -- There are so many stars in our galaxy that even if planets with complex life (animals and plants) are rare - say one for every billion stars - there could still be dozens here in the Milky ...
Reconnaissance Orbiter Reveals Details of a Wetter Mars
Space & Earth / Space Exploration
Oct 28, 2008 |
4.3 / 5 (39) |
18
(PhysOrg.com) -- NASA's Mars Reconnaissance Orbiter has observed a new category of minerals spread across large regions of Mars. This discovery suggests that liquid water remained on the planet's surface a ...
Evidence for ocean on Enceladus: Tiny Saturn Moon Could Be Targeted in Search for Extraterrestrial Life
Space & Earth / Space Exploration
Jul 22, 2009 |
4.6 / 5 (16) |
8
(PhysOrg.com) -- Plumes spewing from a tiny moon of Saturn - a moon roughly the width of Arizona - are filled with molecules that suggest that the moon, Enceladus, is likely another place in the solar system ...
Report: Images from Mars lander show liquid water
Space & Earth / Space Exploration
Mar 11, 2009 |
3.3 / 5 (9) |
2
(AP) -- Did NASA's Phoenix Mars lander find evidence of liquid water before it froze to death?
