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Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to liquid water when in contact with a liquid or solid surface or
cloud condensation nuclei Cloud condensation nuclei (CCNs), also known as cloud seeds, are small particles typically 0.2  µm, or one hundredth the size of a cloud droplet. CCNs are a unique subset of aerosols in the atmosphere on which water vapour condenses. This c ...
within the
atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
. When the transition happens from the gaseous phase into the solid phase directly, the change is called deposition.


Initiation

Condensation is initiated by the formation of atomic/molecular clusters of that species within its gaseous volume—like
rain drop A drop or droplet is a small column of liquid, bounded completely or almost completely by free surfaces. A drop may form when liquid accumulates at the lower end of a tube or other surface boundary, producing a hanging drop called a pendant d ...
or
snow flake A snowflake is a single ice crystal that has achieved a sufficient size, and may have amalgamated with others, which falls through the Earth's atmosphere as snow.Knight, C.; Knight, N. (1973). Snow crystals. Scientific American, vol. 228, no. ...
formation within clouds—or at the contact between such gaseous phase and a liquid or solid surface. In
clouds In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may com ...
, this can be catalyzed by water-nucleating proteins, produced by atmospheric microbes, which are capable of binding gaseous or liquid water molecules.


Reversibility scenarios

A few distinct reversibility scenarios emerge here with respect to the nature of the surface. * absorption into the surface of a liquid (either of the same substance or one of its solvents)—is reversible as
evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...
. * adsorption (as dew droplets) onto solid surface at pressures and temperatures higher than the species' triple point—also reversible as evaporation. * adsorption onto solid surface (as supplemental layers of solid) at pressures and temperatures lower than the species' triple point—is reversible as
sublimation Sublimation or sublimate may refer to: * ''Sublimation'' (album), by Canvas Solaris, 2004 * Sublimation (phase transition), directly from the solid to the gas phase * Sublimation (psychology), a mature type of defense mechanism * Sublimate of mer ...
.


Most common scenarios

Condensation commonly occurs when a vapor is cooled and/or compressed to its saturation limit when the molecular density in the gas phase reaches its maximal threshold. Vapor cooling and compressing equipment that collects condensed liquids is called a "condenser".


Measurement

Psychrometry Psychrometrics (or psychrometry, ; also called hygrometry) is the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. Common applications Although the principles of psychrometry apply to any p ...
measures the rates of condensation through evaporation into the air moisture at various atmospheric pressures and temperatures. Water is the product of its vapor condensation—condensation is the process of such phase conversion.


Applications of condensation

Condensation is a crucial component of distillation, an important laboratory and industrial chemistry application. Because condensation is a naturally occurring phenomenon, it can often be used to generate water in large quantities for human use. Many structures are made solely for the purpose of collecting water from condensation, such as air wells and fog fences. Such systems can often be used to retain soil moisture in areas where active
desertification Desertification is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid. It is the spread of arid areas caused by ...
is occurring—so much so that some organizations educate people living in affected areas about water condensers to help them deal effectively with the situation. It is also a crucial process in forming particle tracks in a cloud chamber. In this case, ions produced by an incident particle act as nucleation centers for the condensation of the vapor producing the visible "cloud" trails. Commercial applications of condensation, by consumers as well as industry, include power generation, water desalination, thermal management, refrigeration, and air conditioning.


Biological adaptation

Numerous living beings use water made accessible by condensation. A few examples of these are the
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
n
thorny devil The thorny devil (''Moloch horridus''), also known commonly as the mountain devil, thorny lizard, thorny dragon, and moloch, is a species of lizard in the family Agamidae. The species is endemic to Australia. It is the sole species in the ...
, the darkling beetles of the Namibian coast, and the
coast redwoods ''Sequoia sempervirens'' ()''Sunset Western Garden Book,'' 1995:606–607 is the sole living species of the genus ''Sequoia (genus), Sequoia'' in the cypress family Cupressaceae (formerly treated in Taxodiaceae). Common names include coast r ...
of the West Coast of the United States.


Condensation in building construction

Condensation in building construction is an unwanted phenomenon as it may cause
dampness Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture), Rock (geology), rock, ceramics, crops, or wood. Water content is used in a wide range of scientific and technical areas, and i ...
,
mold health issues Mold health issues refer to the harmful health effects of molds ("moulds" in British English) and their mycotoxins. However, recent research has shown these adverse health effects are caused not exclusively by molds, but also other microbial agen ...
, wood
rot Rot(s) or rotting may refer to: Decay Organic matter * Rot, decomposition of organic matter ** Dry rot, of wood ** Root rot ** Wet rot, of wood * Necrosis, of tissue Technology * Bit rot, data degradation ** Software rot, a form of bit rot * Di ...
, corrosion, weakening of mortar and masonry walls, and energy penalties due to increased heat transfer. To alleviate these issues, the indoor air humidity needs to be lowered, or air ventilation in the building needs to be improved. This can be done in a number of ways, for example opening windows, turning on extractor fans, using dehumidifiers, drying clothes outside and covering pots and pans whilst cooking. Air conditioning or ventilation systems can be installed that help remove moisture from the air, and move air throughout a building. The amount of water vapor that can be stored in the air can be increased simply by increasing the temperature. However, this can be a double edged sword as most condensation in the home occurs when warm, moisture heavy air comes into contact with a cool surface. As the air is cooled, it can no longer hold as much water vapor. This leads to deposition of water on the cool surface. This is very apparent when central heating is used in combination with single glazed windows in winter. Interstructure condensation may be caused by thermal bridges, insufficient or lacking insulation, damp proofing or insulated glazing.


Table


See also

* Air well (condenser) * Bose–Einstein condensate * Cloud physics * Condenser (heat transfer) *
DNA condensation DNA condensation refers to the process of compacting DNA molecules ''in vitro'' or ''in vivo''. Mechanistic details of DNA packing are essential for its functioning in the process of gene regulation in living systems. Condensed DNA often has surp ...
* Dropwise condensation *
Groasis Waterboxx The Groasis Waterboxx is a device designed to help in growing trees in dry areas. It was invented and developed by Dutch former flower exporter Pieter Hoff,Witkin, JimDeveloping a ‘Water Battery’ for trees''New York Times'', 9 April 2010. Acces ...
*
Kelvin equation The Kelvin equation describes the change in vapour pressure due to a curved liquid–vapor interface, such as the surface of a droplet. The vapor pressure at a convex curved surface is higher than that at a flat surface. The Kelvin equation is de ...
*
Liquefaction of gases Liquefaction of gases is physical conversion of a gas into a liquid state ( condensation). The liquefaction of gases is a complicated process that uses various compressions and expansions to achieve high pressures and very low temperatures, using ...
*
Phase diagram A phase diagram in physical chemistry, engineering, mineralogy, and materials science is a type of chart used to show conditions (pressure, temperature, volume, etc.) at which thermodynamically distinct phases (such as solid, liquid or gaseous ...
* Phase transition * Retrograde condensation * Surface condenser


References

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