 Impact from a water drop causes an upward "rebound" jet surrounded by circular capillary waves. Water is a common chemical substance that is essential to all known forms of life.[1] 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. About 1,460 teratonnes (Tt) of water cover 71% of Earth's surface, 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.[2] Some of the Earth's water is a part of man-made and natural objects near the earth's surface such as water towers, and animal and plant bodies, manufactured products, and food stores. Image File history File links Download high resolution version (1600x1067, 110 KB) Water Droplet File links The following pages link to this file: Water ...
Image File history File links Download high resolution version (1600x1067, 110 KB) Water Droplet File links The following pages link to this file: Water ...
A capillary wave is a wave travelling along a meniscus, whose dynamics are dominated by the effects of surface tension. ...
Water and steam are two different forms of the same chemical substance A chemical substance is any material with a definite chemical composition, no matter where it comes from. ...
For other uses, see Life (disambiguation). ...
A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ...
In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ...
For other uses, see Solid (disambiguation). ...
Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ...
For other meanings see gas (disambiguation). ...
It has been suggested that multiple sections of steam be merged into this article or section. ...
A tonne or metric ton (symbol t), sometimes referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. ...
This article is about Earth as a planet. ...
An aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, silt, or clay) from which groundwater can be usefully extracted using a water well. ...
View of Jupiters active atmosphere, including the Great Red Spot. ...
Vapor (US English) or vapour (British English) is the gaseous state of matter. ...
Cumulus mediocris clouds, as seen from a plane window. ...
Saltwater oceans hold 97.0% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers and lakes 0.6%. Water in these forms moves perpetually through the water cycle of evaporation and transpiration, precipitation, and runoff usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea, about 36 Tt per year. Over land, evaporation and transpiration contribute another 71 Tt per year to the precipitation of 107 Tt per year over land. Some water is trapped for periods in ice caps, glaciers, aquifers, or in lakes, for varying periods, sometimes providing fresh water for life on land. Clean, fresh water is essential to human and other life. In many parts of the world, it is in short supply. Many very important chemical substances, such as salts, sugars, acids, alkalis, some gases (especially oxygen), and many organic molecules dissolve in water. Annual mean sea surface salinity for the World Ocean. ...
Animated map exhibiting the worlds oceanic waters. ...
Glacial and Glaciation redirect here. ...
An ice cap is a dome-shaped ice mass that covers less than 50,000 km² of land area (usually covering a highland area). ...
This bridge across the Danube River links Hungary with Slovakia. ...
A man-made lake in Keukenhof, Netherlands A lake (from Latin lacus) is a body of water or other liquid of considerable size contained on a body of land. ...
The movement of water around, over, and through the Earth is called the water cycle. ...
This article or section is in need of attention from an expert on the subject. ...
Transpiration is the evaporation of excess water from aerial parts and of plants, especially leaves but also stems, flowers and fruits. ...
Run-off, composed of a mixture of water and soil along with any other organic or inorganic substances that may exist in the land, is the product of precipitation, snowmelt, over-irrigation, or other water coming in contact with the earth and carrying matter to streams, rivers, lakes, and other...
For the three letter acronym, see SEA. For the ancient Jewish unit of volume, see Seah (unit). ...
A tonne or metric ton (symbol t), sometimes referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. ...
Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin: wise man or knowing man) in the family Hominidae (the great apes). ...
For other uses, see Salt (disambiguation). ...
Magnification of grains of sugar, showing their monoclinic hemihedral crystalline structure. ...
Acidity redirects here. ...
In chemistry, an alkali (from Arabic: al-qalyالقلوي, القالي ) is a basic, ionic salt of an alkali metal or alkali earth metal element. ...
This article does not cite any references or sources. ...
General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...
An organic compound is any of a large class of chemical compounds whose molecules contain carbon, with exception of carbides, carbonates and carbon oxides. ...
A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ...
Outside of our planet, a significant quantity is thought to exist underground on the planet Mars, on the moons Europa and Enceladus, and on the exoplanets known as HD 189733 b[3] and HD 209458 b.[4] Adjectives: Martian Atmosphere Surface pressure: 0. ...
Apparent magnitude: 5. ...
[5] Atmospheric characteristics Pressure trace, significant spatial variability [6], [7] Water vapour 91% [8] Carbon dioxide 3. ...
Infrared Image of a possible extrasolar planet (lower left) in the Constellation Taurus, taken by the Hubble Space Telescope. ...
HD 189733 b is a gas giant planet that is in very close orbit around the yellow dwarf star HD 189733 A. This planet was discovered in 2005 when astronomers observed the planet transiting across the face of the star. ...
HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ...
 Water covers 71% the Earth's surface; the oceans contain 97.2% of Earth's water. The Antarctic ice sheet, which contains 90% of all fresh water on Earth, is visible at the bottom. Condensed atmospheric water can be seen as clouds, contributing to the earth's albedo. Image File history File linksMetadata Download high resolution version (3000x3002, 6358 KB) The Blue Marble: This photo is of Africa, Antarctica, and the Arabian Peninsula as taken en route to the Moon by Apollo 17s Harrison Schmitt on December 7, 1972. ...
Image File history File linksMetadata Download high resolution version (3000x3002, 6358 KB) The Blue Marble: This photo is of Africa, Antarctica, and the Arabian Peninsula as taken en route to the Moon by Apollo 17s Harrison Schmitt on December 7, 1972. ...
This article is about Earth as a planet. ...
Animated map exhibiting the worlds oceanic waters. ...
A satellite composite image of Antarctica The Antarctic ice sheet is the largest single mass of ice on Earth. ...
Cumulus mediocris clouds, as seen from a plane window. ...
Albedo is the ratio of reflected to incident electromagnetic radiation. ...
[edit] Chemical and physical properties -
Water is the chemical substance with chemical formula H2O: one molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom. Water is a tasteless, odourless liquid at ambient temperature and pressure, and appears colourless in small quantities, although it has its own intrinsic very light blue hue. Ice also appears colourless, and water vapour is essentially invisible as a gas.[5] Water is primarily a liquid under standard conditions, which is not predicted from its relationship to other analogous hydrides of the oxygen family in the periodic table which are gases, such as hydrogen sulfide. Also the elements surrounding oxygen in the periodic table, nitrogen, fluorine, phosphorus, sulfur and chlorine, all combine with hydrogen to produce gases under standard conditions. The reason that oxygen hydride (water) forms a liquid is that it is more electronegative than all of these elements (other than fluorine). Oxygen attracts electrons much more strongly than hydrogen, resulting in a net positive charge on the hydrogen atoms, and a net negative charge on the oxygen atom. The presence of a charge on each of these atoms gives each water molecule a net dipole moment. Electrical attraction between water molecules due to this dipole pulls individual molecules closer together, making it more difficult to separate the molecules and therefore raising the boiling point. This attraction is known as hydrogen bonding. Water can be described as a polar liquid that dissociates disproportionately into the hydronium ion (H3O+(aq)) and an associated hydroxide ion (OH-(aq)). Water is in dynamic equilibrium between the liquid, gas and solid states at standard temperature and pressure, and is the only pure substance found naturally on Earth to be so. IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ...
Dihydrogen monoxide (DHMO) and hydrogen hydroxide (HOH) are technically accurate but rarely-used names for water. ...
A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ...
Molar mass is the mass of one mole of a chemical element or chemical compound. ...
In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: Ï (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is...
In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ...
The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ...
Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ...
The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...
Fahrenheit is a temperature scale named after the German-Dutch physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...
Italic text This article is about the boiling point of liquids. ...
Specific heat capacity, also known simply as specific heat (Symbol: C or c) is the measure of the heat energy required to raise the temperature of a given amount of a substance by one degree. ...
This page provides supplementary chemical data on water. ...
This article describes water from a scientific and technical perspective. ...
Water and steam are two different forms of the same chemical substance A chemical substance is any material with a definite chemical composition, no matter where it comes from. ...
This article or section does not cite any references or sources. ...
General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...
General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...
In science, a molecule is a group of atoms in a definite arrangement held together by chemical bonds. ...
General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...
Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ...
Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ...
A chemical bond is the physical process responsible for the attractive interactions between atoms and molecules, and that which confers stability to diatomic and polyatomic chemical compounds. ...
General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ...
Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ...
The chalcogens (with the ch pronounced with a hard c as in chemistry) are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. ...
For a diagram of the periodic table, see standard periodic table below. ...
Hydrogen sulfide (hydrogen sulphide in British English), H2S, is a colorless, toxic, flammable gas that is responsible for the foul odor of rotten eggs and flatulence. ...
For a diagram of the periodic table, see standard periodic table below. ...
General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...
General Name, Symbol, Number fluorine, F, 9 Chemical series halogens Group, Period, Block 17, 2, p Appearance Yellowish brown gas Atomic mass 18. ...
General Name, Symbol, Number phosphorus, P, 15 Chemical series nonmetals Group, Period, Block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ...
General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ...
General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ...
General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...
It has been suggested that this article or section be merged with electronegativity. ...
This article is about the electromagnetic phenomenon. ...
In chemistry, a hydrogen bond is a type of attractive intermolecular force that exists between two partial electric charges of opposite polarity. ...
In chemistry, hydronium is the common name for the cation H3O+ derived from protonation of water. ...
Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ...
A dynamic equilibrium occurs when two reversible processes occur at the same rate. ...
A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ...
This article does not cite any references or sources. ...
For other uses, see Solid (disambiguation). ...
In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ...
Temperature and air pressure can vary from one place to another on the Earth, and can also vary in the same place with time. ...
[edit] Cohesion and adhesion Water has a partial negative charge (σ-) near the oxygen atom due to the unshared pairs of electrons, and partial positive charges (σ+) near the hydrogen atoms. In water, this happens because the oxygen atom is more electronegative than the hydrogen atoms — that is, it has a stronger "pulling power" on the molecule's electrons, drawing them closer (along with their negative charge) and making the area around the oxygen atom more negative than the area around both of the hydrogen atoms. It has been suggested that this article or section be merged with electronegativity. ...
In physics, the electrostatic force is the force arising between static (that is, non-moving) electric charges. ...
e- redirects here. ...
[edit] Adhesion Water sticks to itself (cohesion) because it is polar. Water also has high adhesion properties because of its polar nature. On extremely clean/smooth glass the water may form a thin film because the molecular forces between glass and water molecules (adhesive forces) are stronger than the cohesive forces. In biological cells and organelles, water is in contact with membrane and protein surfaces that are hydrophilic; that is, surfaces that have a strong attraction to water. Irving Langmuir observed a strong repulsive force between hydrophilic surfaces. To dehydrate hydrophilic surfaces — to remove the strongly held layers of water of hydration — requires doing substantial work against these forces, called hydration forces. These forces are very large but decrease rapidly over a nanometer or less. Their importance in biology has been extensively studied by V. Adrian Parsegian of the National Institute of Health.[6] They are particularly important when cells are dehydrated by exposure to dry atmospheres or to extracellular freezing. Image File history File linksMetadata Download high resolution version (1200x808, 904 KB) Spider Web Covered with Dew Drops. ...
Image File history File linksMetadata Download high resolution version (1200x808, 904 KB) Spider Web Covered with Dew Drops. ...
Dew on a spider web Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening. ...
This article needs additional references or sources for verification. ...
Mercury sticks together because of the cohesive forces. ...
A commonly-used example of a polar compound is water (H2O). ...
Dew drops adhering to a spider web Adhesion is the molecular attraction exerted between bodies in contact. ...
Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ...
Schematic of typical animal cell, showing subcellular components. ...
The adjective hydrophilic describes something that likes water (from Greek hydros = water; philos = friend). ...
Irving Langmuir at home (c. ...
The National Institutes of Health is an institution of the United States government which focuses on medical research. ...
[edit] Surface tension -
 This daisy is under the water level, which has risen gently and smoothly. Surface tension prevents the water from submerging the flower. Water has a high surface tension caused by the strong cohesion between water molecules. This can be seen when small quantities of water are put onto a non-soluble surface such as polythene; the water stays together as drops. Just as significantly, air trapped in surface disturbances forms bubbles, which sometimes last long enough to transfer gas molecules to the water. Another surface tension effect is capillary waves which are the surface ripples that form from around the impact of drops on water surfaces, and some times occur with strong subsurface currents flow to the water surface. The apparent elasticity caused by surface tension drives the waves. In physics, surface tension is an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. ...
Download high resolution version (1200x900, 61 KB)A daisy. ...
Download high resolution version (1200x900, 61 KB)A daisy. ...
Look up daisy in Wiktionary, the free dictionary. ...
In physics, surface tension is an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. ...
Polyethylene or polyethene is one of the simplest and most inexpensive polymers. ...
A capillary wave is a wave travelling along a meniscus, whose dynamics are dominated by the effects of surface tension. ...
[edit] Capillary action -
Capillary action refers to the process of water moving up a narrow tube against the force of gravity. It occurs because water adheres to the sides of the tube, and then surface tension tends to straighten the surface making the surface rise, and more water is pulled up through cohesion. The process is repeated as the water flows up the tube until there is enough water that gravity can counteract the adhesive force. Capillary action, capillarity, or capillary motion is the ability of a substance (the standard reference is to a tube in plants but can be seen readily with porous paper) to draw a substance up against gravity. ...
Capillary action, capillarity, or capillary motion is the ability of a substance (the standard reference is to a tube in plants but can be seen readily with porous paper) to draw a substance up against gravity. ...
Gravity is a force of attraction that acts between bodies that have mass. ...
[edit] Solvation
 High concentrations of dissolved lime make the water of Havasu Falls appear turquoise. Water is a very strong solvent, referred to as the universal solvent, dissolving many types of substances. Substances that will mix well and dissolve in water (e.g. salts) are known as "hydrophilic" (water-loving) substances, while those that do not mix well with water (e.g. fats and oils), are known as "hydrophobic" (water-fearing) substances. The ability of a substance to dissolve in water is determined by whether or not the substance can match or better the strong attractive forces that water molecules generate between other water molecules. If a substance has properties that do not allow it to overcome these strong intermolecular forces, the molecules are "pushed out" from amongst the water and do not dissolve. Image File history File links Download high-resolution version (821x1231, 313 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Water Turquoise (color) User:Moondigger ...
Image File history File links Download high-resolution version (821x1231, 313 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Water Turquoise (color) User:Moondigger ...
This article or section does not adequately cite its references or sources. ...
Havasu Falls Havasu Falls (Havasupai Falls) are waterfalls located in Grand Canyon, Arizona. ...
A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ...
A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ...
For other uses, see Salt (disambiguation). ...
The adjective hydrophilic describes something that likes water (from Greek hydros = water; philos = friend). ...
Figure 1: Basic lipid structure. ...
In chemistry, hydrophobic or lipophilic species, or hydrophobes, tend to be electrically neutral and nonpolar, and thus prefer other neutral and nonpolar solvents or molecular environments. ...
This article or section is in need of attention from an expert on the subject. ...
Precipitation is the formation of a solid in a solution during a chemical reaction. ...
[edit] Electrical conductivity Pure water has a low electrical conductivity, but this increases significantly upon solvation of a small amount of ionic material water such as hydrogen chloride. Thus the risks of electrocution are much greater in water with the usual impurities not found in pure water. Any electrical properties observable in water are from the ions of mineral salts and carbon dioxide dissolved in it. Water does self-ionize where two water molecules become one hydroxide anion and one hydronium cation, but not enough to carry enough electric current to do any work or harm for most operations. In pure water, sensitive equipment can detect a very slight electrical conductivity of 0.055 µS/cm at 25°C. Water can also be electrolyzed into oxygen and hydrogen gases but in the absence of dissolved ions this is a very slow process since very little current is conducted. Electrical conductivity or specific conductivity is a measure of a materials ability to conduct an electric current. ...
R-phrases , S-phrases , , , , Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ...
Sign warning of possible electric shock hazard An electric shock can occur upon contact of a human or animal body with any source of voltage high enough to cause sufficient current flow through the muscles or nerves. ...
An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ...
Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms, and is in a gaseous state in the atmosphere of the Earth. ...
The self-ionization of water is the chemical reaction in which two water molecules react to produce a hydronium (H3O+) and a hydroxide ion (OH-): The reaction is also known as the autoionization or autodissociation of water. ...
Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ...
In chemistry, hydronium is the common name for the cation H3O+ derived from protonation of water. ...
Electric current is the flow (movement) of electric charge. ...
Electrical conductivity or specific conductivity is a measure of a materials ability to conduct an electric current. ...
The siemens (symbol: S) is the SI derived unit of electric conductance. ...
This article is being considered for deletion in accordance with Wikipedias deletion policy. ...
This article is about the chemical process. ...
[edit] Deuterated compounds of water Hydrogen has 3 isotopes, the first being the most common, or having 1 proton and 0 neutrons. More than 95% of water consists of this regular water. There is a second isotope having 1 proton and 1 neutron, called deuterium (short form "D"). This D2O is also known as heavy water and is used in nuclear reactors for storing nuclear wastes. The third isotope has 1 proton and 2 neutrons, called tritium. Tritium is radioactive, and therefore T2O does not exist in nature as creation of the rare molecule would result in almost instantaneous decomposition. D2O is stable; however, it is different from H2O in that D2O is heavier and denser, and it can block alpha and beta rays. D2O occurs naturally in water in very low concentrations. Consumption of pure isolated D2O may affect biochemical processes: ingestion of large amounts impairs kidney function and central nervous system operation. Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in 6500 of hydrogen (~154 PPM). ...
Heavy water is dideuterium oxide, or D2O or 2H2O. It is chemically the same as normal water, H2O, but the hydrogen atoms are of the heavy isotope deuterium, in which the nucleus contains a neutron in addition to the proton found in the nucleus of any hydrogen atom. ...
Core of a small nuclear reactor used for research. ...
Tritium (symbol T or 3H) is a radioactive isotope of hydrogen. ...
Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ...
The kidneys are organs that filter wastes (such as urea) from the blood and excrete them, along with water, as urine. ...
A diagram showing the CNS: 1. ...
[edit] Water, ice, and vapor
[edit] Heat capacity and heat of vaporization -
Water has the second highest specific heat capacity of any known chemical compound, after ammonia, as well as a high heat of vaporization (40.65 kJ mol-1), both of which are a result of the extensive hydrogen bonding between its molecules. These two unusual properties allow water to moderate Earth's climate by buffering large fluctuations in temperature. The heat of vaporization is a physical property of substances. ...
Specific heat capacity, also known simply as specific heat (Symbol: C or c) is the measure of the heat energy required to raise the temperature of a given amount of a substance by one degree. ...
Ammonia is a compound with the formula NH3. ...
The heat of vaporization is a physical property of substances. ...
An example of a quadruple hydrogen bond between a self-assembled dimer complex reported by Meijer and coworkers. ...
[edit] Freezing point A simple but environmentally important and unusual property of water is that its usual solid form, ice, floats on its liquid form. This solid state is not as dense as liquid water because of the geometry of the hydrogen bonds which are formed only at lower temperatures. For almost all other substances the solid form has a greater density than the liquid form. Fresh water at standard atmospheric pressure is most dense at 3.98 °C, and will sink by convection as it cools to that temperature, and if it becomes colder it will rise instead. This reversal will cause deep water to remain warmer than shallower freezing water, so that ice in a body of water will form first at the surface and progress downward, while the majority of the water underneath will hold a constant 4 °C. This effectively insulates a lake floor from the cold. The water will freeze at 0°C (32°F, 273 K), however, it can be supercooled in a fluid state down to its crystal homogeneous nucleation at almost 231 K (−42 °C)[7]. Ice also has a number of more exotic phases not commonly seen (go to the full article on Ice). Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ...
In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: Ï (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is...
Convection in the most general terms refers to the internal movement of currents within fluids (i. ...
Supercooling is the process of chilling a liquid below its freezing point, without its becoming solid. ...
Bubbles in a soft drink each nucleate independently, responding to a decrease in pressure. ...
Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ...
[edit] Triple point -
The triple point of water (the single combination of pressure and temperature at which pure liquid water, ice, and water vapor can coexist in a stable equilibrium) is used to define the kelvin, the SI unit of thermodynamic temperature. As a consequence, water's triple point temperature is an exact value rather than a measured quantity : 273.16 kelvins (0.01 °C) and a pressure of 611.73 pascals (approximately 0.0060373 atm). This is approximately the combination that exists with 100% relative humidity at sea level and the freezing point of water. In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ...
In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ...
The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...
Standard atmosphere (symbol: atm) is a unit of pressure. ...
[edit] Miscibility and condensation -
Water is miscible with many liquids, for example ethanol in all proportions, forming a single homogeneous liquid. On the other hand water and most oils are immiscible usually forming layers according to increasing density from the top. This article or section is not written in the formal tone expected of an encyclopedia article. ...
The chemistry term miscible refers to the property of various liquids that allows them to be mixed together. ...
Grain alcohol redirects here. ...
Synthetic motor oil An oil is any substance that is in a viscous liquid state (oily) at ambient temperatures or slightly warmer, and is both hydrophobic (immiscible with water, literally water fearing) and lipophilic (miscible with other oils, literally fat loving). This general definition includes compound classes with otherwise unrelated...
 Red line shows saturation As a gas, water vapor is completely miscible with air. On the other hand the maximum water vapor pressure that is thermodynamically stable with the liquid (or solid) at a given temperature is relatively low compared with total atmospheric pressure. For example, if the vapor partial pressure[8] is 2% of atmospheric pressure and the air is cooled from 25 deg C, starting at about 22 C water will start to condense, defining the dew point, and creating fog or dew. The reverse process accounts for the fog burning off in the morning. If one raises the humidity at room temperature, say by running a hot shower or a bath, and the temperature stays about the same, the vapor soon reaches the pressure for phase change, and condenses out as steam. A gas in this context is referred to as saturated or 100% relative humidity, when the vapor pressure of water in the air is at the equilibrium with vapor pressure due to (liquid) water; water (or ice, if cool enough) will fail to lose mass through evaporation when exposed to saturated air. Because the amount of water vapor in air is small, relative humidity, the ratio of the partial pressure due to the water vapor to the saturated partial vapor pressure, is much more useful. Water vapor pressure above 100% relative humidity is called super-saturated and can occur if air is rapidly cooled, say by rising suddenly in an updraft. [9] Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
The chemistry term miscible refers to the property of various liquids that allows them to be mixed together. ...
In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. ...
Dew on a spider web The dew point or dewpoint of a given parcel of air is the temperature to which the parcel must be cooled, at constant barometric pressure, for the water vapor component to condense into water, called dew. ...
Golden Gate Bridge in Fog Evening fog obscures Londons Tower Bridge from passers by. ...
Dew on a spider web Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening. ...
[edit] Water on Earth
[edit] Origin and planetary effects Much of the universe's water may be produced as a byproduct of star formation. When stars are born, their birth is accompanied by a strong outward wind of gas and dust. When this outflow of material eventually impacts the surrounding gas, the shock waves that are created compress and heat the gas. The water we observe is quickly produced in this warm dense gas. [10] Image File history File links Habitable_zone-en. ...
Image File history File links Habitable_zone-en. ...
Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ...
In astronomy a habitable zone (HZ) is a region of space where conditions are favorable for life, as it can be found on earth. ...
Media:Example. ...
[edit] Solar distance and Earth gravity The existence of liquid water, and to a lesser extent its gaseous and solid forms, on Earth is vital to the existence of life on Earth. The Earth is located in the habitable zone of the solar system; if it were slightly closer to or further from the Sun (about 5%, or 8 million kilometers or so), the conditions which allow the three forms to be present simultaneously would be far less likely to exist. [11] This article is about the tv programme Life on Earth. ...
In astronomy a habitable zone (HZ) is a region of space where conditions are favorable for life, as it can be found on earth. ...
Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ...
“Sol†redirects here. ...
Earth's mass allows gravity to hold an atmosphere. Water vapor and carbon dioxide in the atmosphere provide a greenhouse effect which helps maintain a relatively steady surface temperature. If Earth were smaller, a thinner atmosphere would cause temperature extremes preventing the accumulation of water except in polar ice caps (as on Mars). Gravity is a force of attraction that acts between bodies that have mass. ...
Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ...
A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ...
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Mars is the fourth planet from the Sun in the solar system, named after the Roman god of war (the counterpart of the Greek Ares), on account of its blood red color as viewed in the night sky. ...
It has been proposed that life itself may maintain the conditions that have allowed its continued existence. The surface temperature of Earth has been relatively constant through geologic time despite varying levels of incoming solar radiation (insolation), indicating that a dynamic process governs Earth's temperature via a combination of greenhouse gases and surface or atmospheric albedo. This proposal is known as the Gaia hypothesis. The table and timeline of geologic periods presented here is in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy. ...
TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in...
Albedo is the ratio of reflected to incident electromagnetic radiation. ...
Italic textBold textLink titleLink title. ...
The state of water also depends on a planet's gravity. If a planet is sufficiently massive, the water on it may be solid even at high temperatures, because of the high pressure caused by gravity. [1]
High tide (left) and low tide (right). -
Tides are the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the oceans. Tides cause changes in the depth of the marine and estuarine water bodies and produce oscillating currents known as tidal streams. The changing tide produced at a given location is the result of the changing positions of the Moon and Sun relative to the Earth coupled with the effects of Earth rotation and the local bathymetry. The strip of seashore that is submerged at high tide and exposed at low tide, the intertidal zone, is an important ecological product of ocean tides. The bay of Fundy at high tide This picture was taken in about 1972 by me. ...
The Bay of Fundy at low tide taken in 1972 File links The following pages link to this file: Tide Bay of Fundy Categories: GFDL images ...
“Ebb tide†redirects here. ...
“Ebb tide†redirects here. ...
This article is about Earth as a planet. ...
Animated map exhibiting the worlds oceanic waters. ...
Comet Shoemaker-Levy 9 after breaking up under the influence of Jupiters tidal forces. ...
Apparent magnitude: up to -12. ...
“Sol†redirects here. ...
Rio de la Plata estuary Wikimedia Commons has media related to: Estuaries An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ...
In the inertial frame of reference (upper part of the picture), the black object moves in a straight line. ...
Bathymetry is the underwater equivalent to topography. ...
A rock, seen at low tide, exhibiting typical intertidal zonation. ...
[edit] Water cycle The biosphere can be roughly divided into oceans, land, and atmosphere. Water moves perpetually through each of these regions in the water cycle consisting of following transfer processes: A false-color composite of global oceanic and terrestrial photoautotroph abundance, from September 1997 to August 2000. ...
The movement of water around, over, and through the Earth is called the water cycle. ...
- evaporation from oceans and other water bodies into the air and transpiration from land plants and animals into air.
- precipitation, from water vapor condensing from the air and falling to earth or ocean.
- runoff from the land usually reaching the sea.
Most water vapor over the oceans returns to the oceans, but winds carry water vapor over land at the same rate as runoff into the sea, about 36 Tt per year. Over land, evaporation and transpiration contribute another 71 Tt per year. Precipitation, at a rate of 107 Tt per year over land, has several forms: most commonly rain, snow, and hail, with some contribution from fog and dew. Condensed water in the air may also refract sunlight to produce rainbows. This article or section is in need of attention from an expert on the subject. ...
Transpiration is the evaporation of excess water from aerial parts and of plants, especially leaves but also stems, flowers and fruits. ...
Run-off, composed of a mixture of water and soil along with any other organic or inorganic substances that may exist in the land, is the product of precipitation, snowmelt, over-irrigation, or other water coming in contact with the earth and carrying matter to streams, rivers, lakes, and other...
For the three letter acronym, see SEA. For the ancient Jewish unit of volume, see Seah (unit). ...
A tonne or metric ton (symbol t), sometimes referred to as a metric tonne, is a measurement of mass equal to 1,000 kilograms. ...
Rain is a type of precipitation which forms when separate drops of water fall to the Earths surface from clouds. ...
Snow is a type of precipitation in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. ...
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Golden Gate Bridge in Fog Evening fog obscures Londons Tower Bridge from passers by. ...
Dew on a spider web Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening. ...
This article refers to refraction in waves. ...
Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ...
Full featured double rainbow in Wrangell-St. ...
Water runoff often collects over watersheds flowing into rivers. Some of this is diverted to irrigation for agriculture. Rivers and seas offer opportunity for travel and commerce. Through erosion, runoff shapes the environment creating river valleys and deltas which provide rich soil and level ground for the establishment of population centers. This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ...
Irrigation is the artificial application of water to the soil. ...
Statue dedicated to the traveller. ...
This article does not cite any references or sources. ...
Severe soil erosion in a wheat field near Washington State University, USA. For erosion as an operation of Mathematical morphology, see Erosion (morphology) Erosion is displacement of solids (soil, mud, rock and other particles) by the agents of ocean currents, wind, water, or ice by downward or down-slope movement...
Fljótsdalur in East Iceland, a rather flat valley A valley or a low area between two hills dale (in Scotland, a glen) is a landform, which can range from a few square kilometres to hundreds or even thousands of square kilometres in area. ...
Nile River delta, as seen from Earth orbit. ...
[edit] Fresh water storage Some runoff water is trapped for periods, for example in lakes. At high altitude, during winter, and in the far north and south, snow collects in ice caps, snow pack and glaciers. Water also infiltrates the ground and goes into aquifers. This groundwater later flows back to the surface in springs, or more spectacularly in hot springs and geysers. Groundwater is also extracted artificially in wells. This water storage is important, since clean, fresh water is essential to human and other land-based life. In many parts of the world, it is in short supply. |
