Tyvek ( / ˈ t aɪ . v ɛ k / ) is a brand of synthetic flashspun high-density polyethylene fibers . The name Tyvek is a registered trademark of the American multinational chemical company DuPont , which discovered and commercialized Tyvek in the late 1950s and early 1960s.
80-419: Tyvek's properties—such as being difficult to tear but easily cut, and waterproof against liquids while allowing water vapor to penetrate—have led to it being used in a variety of applications. Tyvek is often used as housewrap , a synthetic material used to protect buildings during construction, or as personal protective equipment (PPE). Tyvek is a nonwoven product consisting of spun bond olefin fiber . It
160-447: A greenhouse gas and warming feedback, contributing more to total greenhouse effect than non-condensable gases such as carbon dioxide and methane . Use of water vapor, as steam , has been important for cooking, and as a major component in energy production and transport systems since the industrial revolution . Water vapor is a relatively common atmospheric constituent, present even in the solar atmosphere as well as every planet in
240-424: A certain amount of time, if the cloud continues to generate and store more static electricity , the barrier that was created by the atmospheric water vapor will ultimately break down from the stored electrical potential energy. This energy will be released to a local oppositely charged region, in the form of lightning. The strength of each discharge is directly related to the atmospheric permittivity, capacitance, and
320-401: A clothes line will dry (by evaporation) more rapidly on a windy day than on a still day. Three key parts to evaporation are heat, atmospheric pressure (determines the percent humidity), and air movement. On a molecular level, there is no strict boundary between the liquid state and the vapor state. Instead, there is a Knudsen layer , where the phase is undetermined. Because this layer is only
400-528: A crystalline structure or alter an existing one, sometimes resulting in characteristic color changes that can be used for measurement . Measuring the quantity of water vapor in a medium can be done directly or remotely with varying degrees of accuracy. Remote methods such electromagnetic absorption are possible from satellites above planetary atmospheres. Direct methods may use electronic transducers, moistened thermometers or hygroscopic materials measuring changes in physical properties or dimensions. Water vapor
480-502: A disproportionate impact, which is why jet traffic has a disproportionately high warming effect. Oxidation of methane is also a major source of water vapour in the stratosphere, and adds about 15% to methane's global warming effect. In the absence of other greenhouse gases, Earth's water vapor would condense to the surface; this has likely happened , possibly more than once. Scientists thus distinguish between non-condensable (driving) and condensable (driven) greenhouse gases, i.e.,
560-607: A durable fabric that could be cut with a blade. While the product Tyvek was used since 1959, DuPont did not trademark the actual brand until 1965, making it available for commercial purposes in April 1967. By 1970, Tyvek had reached the mainstream construction industry on both a national and global scale. Its products were often used for the construction of houses due to its ability to keep out liquid, while allowing vapor through. In 1972, DuPont released Tyvek packaging for sterile instruments that were to be used by surgeons and doctors in
640-429: A few molecules thick, at a macroscopic scale a clear phase transition interface cannot be seen. Liquids that do not evaporate visibly at a given temperature in a given gas (e.g., cooking oil at room temperature ) have molecules that do not tend to transfer energy to each other in a pattern sufficient to frequently give a molecule the heat energy necessary to turn into vapor. However, these liquids are evaporating. It
720-453: A fraction of the molecules in a liquid have enough heat energy to escape from the liquid. The evaporation will continue until an equilibrium is reached when the evaporation of the liquid is equal to its condensation. In an enclosed environment, a liquid will evaporate until the surrounding air is saturated. Evaporation is an essential part of the water cycle . The sun (solar energy) drives evaporation of water from oceans , lakes, moisture in
800-436: A human hair). The nondirectional fibers (plexifilaments) are first spun and then bonded by heat and pressure, without binders. Tyvek is also: Water vapor Water vapor , water vapour or aqueous vapor is the gaseous phase of water . It is one state of water within the hydrosphere . Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice . Water vapor
880-484: A key role in lightning production in the atmosphere. From cloud physics , usually clouds are the real generators of static charge as found in Earth's atmosphere. The ability of clouds to hold massive amounts of electrical energy is directly related to the amount of water vapor present in the local system. The amount of water vapor directly controls the permittivity of the air. During times of low humidity, static discharge
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#1732845294524960-672: A layer of liquid water about 25 mm deep. The mean annual precipitation for the planet is about 1 metre, a comparison which implies a rapid turnover of water in the air – on average, the residence time of a water molecule in the troposphere is about 9 to 10 days. Global mean water vapour is about 0.25% of the atmosphere by mass and also varies seasonally, in terms of contribution to atmospheric pressure between 2.62 hPa in July and 2.33 hPa in December. IPCC AR6 expresses medium confidence in increase of total water vapour at about 1-2% per decade; it
1040-529: A liquid can evaporate if they have more than the minimum amount of kinetic energy required for vaporization. Note: Air is used here as a common example of the surrounding gas; however, other gases may hold that role. In the US, the National Weather Service measures, at various outdoor locations nationwide, the actual rate of evaporation from a standardized "pan" open water surface. Others do likewise around
1120-432: A liquid to evaporate, they must be located near the surface, they have to be moving in the proper direction, and have sufficient kinetic energy to overcome liquid-phase intermolecular forces . When only a small proportion of the molecules meet these criteria, the rate of evaporation is low. Since the kinetic energy of a molecule is proportional to its temperature, evaporation proceeds more quickly at higher temperatures. As
1200-565: A major constituent of the atmosphere of dwarf planet , Ceres , largest object in the asteroid belt The detection was made by using the far-infrared abilities of the Herschel Space Observatory . The finding is unexpected because comets , not asteroids , are typically considered to "sprout jets and plumes." According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." Scientists studying Mars hypothesize that if water moves about
1280-414: A number of other formulae which can be used. Under certain conditions, such as when the boiling temperature of water is reached, a net evaporation will always occur during standard atmospheric conditions regardless of the percent of relative humidity. This immediate process will dispel massive amounts of water vapor into a cooler atmosphere. Exhaled air is almost fully at equilibrium with water vapor at
1360-693: A program in the United States where disposable clothing, coveralls, lab coats, medical packaging and other non-hazardous Tyvek disposable garments can be recycled, as well as providing a mail-in recycling program for envelopes. As plastic bag recycling has become more prevalent in the United States, the American Chemistry Council has recommended that plastic film drop-off recycling locations should be able to accept Tyvek. According to DuPont's website, Tyvek fibers are 0.5–10 μm (2.0 × 10–0.000394 in) (compared to 75 μm (0.0030 in) for
1440-431: A surface, a net warming occurs on that surface. The water molecule brings heat energy with it. In turn, the temperature of the atmosphere drops slightly. In the atmosphere, condensation produces clouds, fog and precipitation (usually only when facilitated by cloud condensation nuclei ). The dew point of an air parcel is the temperature to which it must cool before water vapor in the air begins to condense. Condensation in
1520-411: A variety of substrates, DuPont recommends starch , dextrin , casein , and animal-based adhesives over most synthetic-based adhesives , emphasizing the effectiveness of water-based and quick-drying glues. DuPont also claims that the following adhesives are highly effective: Heat sealing can be used to melt Tyvek and cause it to bond to itself, but this form of bonding tends to create puckers in
1600-422: A working medium which shuttles forth and back between both. The upper temperature level is given by the soil or water surface of the Earth, which absorbs the incoming sun radiation and warms up, evaporating water. The moist and warm air at the ground is lighter than its surroundings and rises up to the upper limit of the troposphere. There the water molecules radiate their thermal energy into outer space, cooling down
1680-401: Is a by-product of respiration in plants and animals. Its contribution to the pressure, increases as its concentration increases. Its partial pressure contribution to air pressure increases, lowering the partial pressure contribution of the other atmospheric gases (Dalton's Law) . The total air pressure must remain constant. The presence of water vapor in the air naturally dilutes or displaces
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#17328452945241760-406: Is an important greenhouse gas owing to the presence of the hydroxyl bond which strongly absorbs in the infra-red . Water vapor is the "working medium" of the atmospheric thermodynamic engine which transforms heat energy from sun irradiation into mechanical energy in the form of winds. Transforming thermal energy into mechanical energy requires an upper and a lower temperature level, as well as
1840-425: Is defined as thermal energy and occurs only when there is differential in the temperature of the water molecules. Liquid water that becomes water vapor takes a parcel of heat with it, in a process called evaporative cooling . The amount of water vapor in the air determines how frequently molecules will return to the surface. When a net evaporation occurs, the body of water will undergo a net cooling directly related to
1920-411: Is expected to increase by around 7% per °C of warming. Episodes of surface geothermal activity, such as volcanic eruptions and geysers, release variable amounts of water vapor into the atmosphere. Such eruptions may be large in human terms, and major explosive eruptions may inject exceptionally large masses of water exceptionally high into the atmosphere, but as a percentage of total atmospheric water,
2000-411: Is extremely valuable to certain scientific disciplines, a dramatic example being the collection of meteorites that are left exposed in unparalleled numbers and excellent states of preservation. Sublimation is important in the preparation of certain classes of biological specimens for scanning electron microscopy . Typically the specimens are prepared by cryofixation and freeze-fracture , after which
2080-405: Is just that the process is much slower and thus significantly less visible. If evaporation takes place in an enclosed area, the escaping molecules accumulate as a vapor above the liquid. Many of the molecules return to the liquid, with returning molecules becoming more frequent as the density and pressure of the vapor increases. When the process of escape and return reaches an equilibrium ,
2160-406: Is lighter or less dense than dry air . At equivalent temperatures it is buoyant with respect to dry air, whereby the density of dry air at standard temperature and pressure (273.15 K, 101.325 kPa) is 1.27 g/L and water vapor at standard temperature has a vapor pressure of 0.6 kPa and the much lower density of 0.0048 g/L. Water vapor and dry air density calculations at 0 °C: At
2240-433: Is not merely below its boiling point (100 °C), but at altitude it goes below its freezing point (0 °C), due to water's highly polar attraction . When combined with its quantity, water vapor then has a relevant dew point and frost point , unlike e. g., carbon dioxide and methane. Water vapor thus has a scale height a fraction of that of the bulk atmosphere, as the water condenses and exits , primarily in
2320-402: Is one of the principal uncertainties in modern climate modeling.' Evaporation is an endothermic process , since heat is absorbed during evaporation. Fuel droplets vaporize as they receive heat by mixing with the hot gases in the combustion chamber. Heat (energy) can also be received by radiation from any hot refractory wall of the combustion chamber. Internal combustion engines rely upon
2400-406: Is quick and easy. During times of higher humidity, fewer static discharges occur. Permittivity and capacitance work hand in hand to produce the megawatt outputs of lightning. After a cloud, for instance, has started its way to becoming a lightning generator, atmospheric water vapor acts as a substance (or insulator ) that decreases the ability of the cloud to discharge its electrical energy. Over
2480-497: Is referred to as a 'feedback', because it amplifies the effect of forces that initially cause the warming. So, it is a greenhouse gas. Whenever a water molecule leaves a surface and diffuses into a surrounding gas, it is said to have evaporated . Each individual water molecule which transitions between a more associated (liquid) and a less associated (vapor/gas) state does so through the absorption or release of kinetic energy . The aggregate measurement of this kinetic energy transfer
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2560-413: Is that water vapor amounts over land areas decrease more in winter months than adjacent ocean areas do. This is largely because air temperatures over land drop more in the winter than temperatures over the ocean. Water vapor condenses more rapidly in colder air. As water vapor absorbs light in the visible spectral range, its absorption can be used in spectroscopic applications (such as DOAS ) to determine
2640-469: Is the enthalpy of vaporization , and R is the universal gas constant . The rate of evaporation in an open system is related to the vapor pressure found in a closed system. If a liquid is heated, when the vapor pressure reaches the ambient pressure the liquid will boil . The ability for a molecule of a liquid to evaporate is based largely on the amount of kinetic energy an individual particle may possess. Even at lower temperatures, individual molecules of
2720-517: Is the process by which water molecules directly leave the surface of ice without first becoming liquid water. Sublimation accounts for the slow mid-winter disappearance of ice and snow at temperatures too low to cause melting. Antarctica shows this effect to a unique degree because it is by far the continent with the lowest rate of precipitation on Earth. As a result, there are large areas where millennial layers of snow have sublimed, leaving behind whatever non-volatile materials they had contained. This
2800-492: Is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation . It is less dense than most of the other constituents of air and triggers convection currents that can lead to clouds and fog. Being a component of Earth's hydrosphere and hydrologic cycle, it is particularly abundant in Earth's atmosphere , where it acts as
2880-488: Is used as a lifting gas by a thermal airship the water vapor is heated to form steam so that its vapor pressure is greater than the surrounding air pressure in order to maintain the shape of a theoretical "steam balloon", which yields approximately 60% the lift of helium and twice that of hot air. The amount of water vapor in an atmosphere is constrained by the restrictions of partial pressures and temperature. Dew point temperature and relative humidity act as guidelines for
2960-485: The Solar System and many astronomical objects including natural satellites , comets and even large asteroids . Likewise the detection of extrasolar water vapor would indicate a similar distribution in other planetary systems. Water vapor can also be indirect evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Water vapor, which reacts to temperature changes,
3040-491: The atmosphere . The percentage of water vapor in surface air varies from 0.01% at -42 °C (-44 °F) to 4.24% when the dew point is 30 °C (86 °F). Over 99% of atmospheric water is in the form of vapour, rather than liquid water or ice, and approximately 99.13% of the water vapour is contained in the troposphere . The condensation of water vapor to the liquid or ice phase is responsible for clouds , rain, snow, and other precipitation , all of which count among
3120-509: The troposphere , the lowest layer of the atmosphere. Carbon dioxide ( CO 2 ) and methane , being well-mixed in the atmosphere, tend to rise above water vapour. The absorption and emission of both compounds contribute to Earth's emission to space, and thus the planetary greenhouse effect . This greenhouse forcing is directly observable, via distinct spectral features versus water vapor, and observed to be rising with rising CO 2 levels. Conversely, adding water vapor at high altitudes has
3200-444: The above water vapor feedback. Fog and clouds form through condensation around cloud condensation nuclei . In the absence of nuclei, condensation will only occur at much lower temperatures. Under persistent condensation or deposition, cloud droplets or snowflakes form, which precipitate when they reach a critical mass. Atmospheric concentration of water vapour is highly variable between locations and times, from 10 ppmv in
3280-564: The amount of water vapor in the atmosphere. This is done operationally, e.g. from the Global Ozone Monitoring Experiment (GOME) spectrometers on ERS (GOME) and MetOp (GOME-2). The weaker water vapor absorption lines in the blue spectral range and further into the UV up to its dissociation limit around 243 nm are mostly based on quantum mechanical calculations and are only partly confirmed by experiments. Water vapor plays
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3360-434: The atmosphere and the water surface determine the equilibrium vapor pressure; 100% relative humidity occurs when the partial pressure of water vapor is equal to the equilibrium vapor pressure. This condition is often referred to as complete saturation. Humidity ranges from 0 grams per cubic metre in dry air to 30 grams per cubic metre (0.03 ounce per cubic foot) when the vapor is saturated at 30 °C. Sublimation
3440-494: The atmosphere attenuates radar signals. In addition, atmospheric water will reflect and refract signals to an extent that depends on whether it is vapor, liquid or solid. Generally, radar signals lose strength progressively the farther they travel through the troposphere. Different frequencies attenuate at different rates, such that some components of air are opaque to some frequencies and transparent to others. Radio waves used for broadcasting and other communication experience
3520-502: The atmosphere forms cloud droplets. Also, a net condensation of water vapor occurs on surfaces when the temperature of the surface is at or below the dew point temperature of the atmosphere. Deposition is a phase transition separate from condensation which leads to the direct formation of ice from water vapor. Frost and snow are examples of deposition. There are several mechanisms of cooling by which condensation occurs: 1) Direct loss of heat by conduction or radiation. 2) Cooling from
3600-460: The body temperature. In the cold air the exhaled vapor quickly condenses, thus showing up as a fog or mist of water droplets and as condensation or frost on surfaces. Forcibly condensing these water droplets from exhaled breath is the basis of exhaled breath condensate , an evolving medical diagnostic test. Controlling water vapor in air is a key concern in the heating, ventilating, and air-conditioning (HVAC) industry. Thermal comfort depends on
3680-455: The broken surface is freeze-etched, being eroded by exposure to vacuum until it shows the required level of detail. This technique can display protein molecules, organelle structures and lipid bilayers with very low degrees of distortion. Water vapor will only condense onto another surface when that surface is cooler than the dew point temperature, or when the water vapor equilibrium in air has been exceeded. When water vapor condenses onto
3760-454: The coldest air to 5% (50 000 ppmv) in humid tropical air, and can be measured with a combination of land observations, weather balloons and satellites. The water content of the atmosphere as a whole is constantly depleted by precipitation. At the same time it is constantly replenished by evaporation, most prominently from oceans, lakes, rivers, and moist earth. Other sources of atmospheric water include combustion, respiration, volcanic eruptions,
3840-455: The constellation Pegasus, provides the first evidence of atmospheric water vapor beyond the Solar System. A star called CW Leonis was found to have a ring of vast quantities of water vapor circling the aging, massive star . A NASA satellite designed to study chemicals in interstellar gas clouds, made the discovery with an onboard spectrometer. Most likely, "the water vapor was vaporized from
3920-416: The drop in air pressure which occurs with uplift of air, also known as adiabatic cooling . Air can be lifted by mountains, which deflect the air upward, by convection, and by cold and warm fronts. 3) Advective cooling - cooling due to horizontal movement of air. A number of chemical reactions have water as a product. If the reactions take place at temperatures higher than the dew point of the surrounding air
4000-476: The equator as the seasons change. This band of humidity is part of the Intertropical Convergence Zone , where the easterly trade winds from each hemisphere converge and produce near-daily thunderstorms and clouds. Farther from the equator, water vapor concentrations are high in the hemisphere experiencing summer and low in the one experiencing winter. Another pattern that shows up in the time series
4080-423: The faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid decreases. This phenomenon is also called evaporative cooling . This is why evaporating sweat cools the human body. Evaporation also tends to proceed more quickly with higher flow rates between the gaseous and liquid phase and in liquids with higher vapor pressure . For example, laundry on
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#17328452945244160-531: The highest amounts (6 centimeters) appear in dark blue. Areas of missing data appear in shades of gray. The maps are based on data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on NASA's Aqua satellite. The most noticeable pattern in the time series is the influence of seasonal temperature changes and incoming sunlight on water vapor. In the tropics, a band of extremely humid air wobbles north and south of
4240-404: The loss of water. In the US, the National Weather Service measures the actual rate of evaporation from a standardized "pan" open water surface outdoors, at various locations nationwide. Others do likewise around the world. The US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches per year. Formulas can be used for calculating
4320-725: The medical field. In 2017, the DuPont company merged with another chemical company , The Dow Chemical Company to form DowDuPont . DowDuPont currently manufactures Tyvek at the Spruance plant in Richmond, Virginia , and in Sandweiler - Contern , Luxembourg . In 2018, DowDuPont announced plans to expand the Tyvek production capacity of the Sandweiler-Contern factory. To bond Tyvek to both itself and
4400-437: The moist air conditions. Non-human comfort situations are called refrigeration , and also are affected by water vapor. For example, many food stores, like supermarkets, utilize open chiller cabinets, or food cases , which can significantly lower the water vapor pressure (lowering humidity). This practice delivers several benefits as well as problems. Gaseous water represents a small but environmentally significant constituent of
4480-410: The molecules of the liquid collide, they transfer energy to each other based on how they collide. When a molecule near the surface absorbs enough energy to overcome the vapor pressure , it will escape and enter the surrounding air as a gas. When evaporation occurs, the energy removed from the vaporized liquid will reduce the temperature of the liquid, resulting in evaporative cooling. On average, only
4560-468: The most significant elements of what we experience as weather. Less obviously, the latent heat of vaporization , which is released to the atmosphere whenever condensation occurs, is one of the most important terms in the atmospheric energy budget on both local and global scales. For example, latent heat release in atmospheric convection is directly responsible for powering destructive storms such as tropical cyclones and severe thunderstorms . Water vapor
4640-533: The most used reference formula is the Goff-Gratch equation for the SVP over liquid water below zero degrees Celsius: where T , temperature of the moist air, is given in units of kelvin , and p is given in units of millibars ( hectopascals ). The formula is valid from about −50 to 102 °C; however there are a very limited number of measurements of the vapor pressure of water over supercooled liquid water. There are
4720-431: The oceans, clouds and continents of the Earth. Vapor surrounds the planet but is unevenly distributed. The image loop on the right shows monthly average of water vapor content with the units are given in centimeters, which is the precipitable water or equivalent amount of water that could be produced if all the water vapor in the column were to condense. The lowest amounts of water vapor (0 centimeters) appear in yellow, and
4800-440: The other air components as its concentration increases. This can have an effect on respiration. In very warm air (35 °C) the proportion of water vapor is large enough to give rise to the stuffiness that can be experienced in humid jungle conditions or in poorly ventilated buildings. Water vapor has lower density than that of air and is therefore buoyant in air but has lower vapor pressure than that of air. When water vapor
4880-445: The otherwise flat material. Dielectric bonding can be effective in some circumstances, as is ultrasonic welding . Though Tyvek superficially resembles paper (for example, it can be written and printed on), it is plastic , and it cannot be recycled with paper. Some Tyvek products are marked with the #2 resin-code for HDPE , and can be collected with plastic bottles as part of some municipal curbside recycling programs. DuPont runs
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#17328452945244960-458: The planet, it does so as vapor. The brilliance of comet tails comes largely from water vapor. On approach to the Sun , the ice many comets carry sublimes to vapor. Knowing a comet's distance from the sun, astronomers may deduce the comet's water content from its brilliance. Water vapor has also been confirmed outside the Solar System. Spectroscopic analysis of HD 209458 b , an extrasolar planet in
5040-486: The process of water vapor in the water cycle . Energy input, such as sunlight, can trigger more evaporation on an ocean surface or more sublimation on a chunk of ice on top of a mountain. The balance between condensation and evaporation gives the quantity called vapor partial pressure . The maximum partial pressure ( saturation pressure ) of water vapor in air varies with temperature of the air and water vapor mixture. A variety of empirical formulas exist for this quantity;
5120-454: The rate of evaporation from a water surface such as a swimming pool. In some countries, the evaporation rate far exceeds the precipitation rate. Evaporative cooling is restricted by atmospheric conditions . Humidity is the amount of water vapor in the air. The vapor content of air is measured with devices known as hygrometers . The measurements are usually expressed as specific humidity or percent relative humidity . The temperatures of
5200-640: The role of such processes is trivial. The relative concentrations of the various gases emitted by volcanoes varies considerably according to the site and according to the particular event at any one site. However, water vapor is consistently the commonest volcanic gas ; as a rule, it comprises more than 60% of total emissions during a subaerial eruption . Atmospheric water vapor content is expressed using various measures. These include vapor pressure, specific humidity , mixing ratio, dew point temperature, and relative humidity . Because water molecules absorb microwaves and other radio wave frequencies, water in
5280-421: The same effect. Water vapor reflects radar to a lesser extent than do water's other two phases. In the form of drops and ice crystals, water acts as a prism, which it does not do as an individual molecule ; however, the existence of water vapor in the atmosphere causes the atmosphere to act as a giant prism. A comparison of GOES-12 satellite images shows the distribution of atmospheric water vapor relative to
5360-404: The same temperature, a column of dry air will be denser or heavier than a column of air containing any water vapor, the molar mass of diatomic nitrogen and diatomic oxygen both being greater than the molar mass of water. Thus, any volume of dry air will sink if placed in a larger volume of moist air. Also, a volume of moist air will rise or be buoyant if placed in a larger region of dry air. As
5440-428: The soil, and other sources of water. In hydrology , evaporation and transpiration (which involves evaporation within plant stomata ) are collectively termed evapotranspiration . Evaporation of water occurs when the surface of the liquid is exposed, allowing molecules to escape and form water vapor; this vapor can then rise up and form clouds. With sufficient energy, the liquid will turn into vapor. For molecules of
5520-553: The source's charge generating ability. Water vapor is common in the Solar System and by extension, other planetary systems . Its signature has been detected in the atmospheres of the Sun, occurring in sunspots . The presence of water vapor has been detected in the atmospheres of all seven extraterrestrial planets in the Solar System, the Earth's Moon, and the moons of other planets, although typically in only trace amounts. Geological formations such as cryogeysers are thought to exist on
5600-416: The surface of several icy moons ejecting water vapor due to tidal heating and may indicate the presence of substantial quantities of subsurface water. Plumes of water vapor have been detected on Jupiter's moon Europa and are similar to plumes of water vapor detected on Saturn's moon Enceladus . Traces of water vapor have also been detected in the stratosphere of Titan . Water vapor has been found to be
5680-443: The surfaces of orbiting comets." Other exoplanets with evidence of water vapor include HAT-P-11b and K2-18b . Evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. A high concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidity affects rate of evaporation of water. When
5760-413: The surrounding air. The upper atmosphere constitutes the lower temperature level of the atmospheric thermodynamic engine. The water vapor in the now cold air condenses out and falls down to the ground in the form of rain or snow. The now heavier cold and dry air sinks down to ground as well; the atmospheric thermodynamic engine thus establishes a vertical convection, which transports heat from the ground into
5840-451: The temperature rises the proportion of water vapor in the air increases, and its buoyancy will increase. The increase in buoyancy can have a significant atmospheric impact, giving rise to powerful, moisture rich, upward air currents when the air temperature and sea temperature reaches 25 °C or above. This phenomenon provides a significant driving force for cyclonic and anticyclonic weather systems (typhoons and hurricanes). Water vapor
5920-406: The transpiration of plants, and various other biological and geological processes. At any given time there is about 1.29 x 10 litres (3.4 x 10 gal.) of water in the atmosphere. The atmosphere holds 1 part in 2500 of the fresh water, and 1 part in 100,000 of the total water on Earth. The mean global content of water vapor in the atmosphere is roughly sufficient to cover the surface of the planet with
6000-418: The upper atmosphere, where the water molecules can radiate it to outer space. Due to the Earth's rotation and the resulting Coriolis forces, this vertical atmospheric convection is also converted into a horizontal convection, in the form of cyclones and anticyclones, which transport the water evaporated over the oceans into the interior of the continents, enabling vegetation to grow. Water in Earth's atmosphere
6080-500: The vapor is said to be "saturated", and no further change in either vapor pressure and density or liquid temperature will occur. For a system consisting of vapor and liquid of a pure substance, this equilibrium state is directly related to the vapor pressure of the substance, as given by the Clausius–Clapeyron relation : where P 1 , P 2 are the vapor pressures at temperatures T 1 , T 2 respectively, Δ H vap
6160-425: The vaporization of the fuel in the cylinders to form a fuel/air mixture in order to burn well. The chemically correct air/fuel mixture for total burning of gasoline has been determined to be 15 parts air to one part gasoline or 15/1 by weight. Changing this to a volume ratio yields 8000 parts air to one part gasoline or 8,000/1 by volume. Thin films may be deposited by evaporating a substance and condensing it onto
6240-694: The water will be formed as vapor and increase the local humidity, if below the dew point local condensation will occur. Typical reactions that result in water formation are the burning of hydrogen or hydrocarbons in air or other oxygen containing gas mixtures, or as a result of reactions with oxidizers. In a similar fashion other chemical or physical reactions can take place in the presence of water vapor resulting in new chemicals forming such as rust on iron or steel, polymerization occurring (certain polyurethane foams and cyanoacrylate glues cure with exposure to atmospheric humidity) or forms changing such as where anhydrous chemicals may absorb enough vapor to form
6320-469: The world. The US data is collected and compiled into an annual evaporation map. The measurements range from under 30 to over 120 inches (3,000 mm) per year. Because it typically takes place in a complex environment, where 'evaporation is an extremely rare event', the mechanism for the evaporation of water is not completely understood. Theoretical calculations require prohibitively long and large computer simulations. 'The rate of evaporation of liquid water
6400-413: Was first discovered in 1955 by a researcher for the DuPont textile company working in an experimental lab, who noticed a type of white fluff coming out of a pipe. That fluff was a form of polyethylene , which DuPont requested a patent for within a year of the discovery. After technologies improved during the next few years, in 1959 DuPont discovered that when the fluff was spun at high speeds it produced
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