—condensational, adj. —condensative, adj./kon'den say"sheuhn, -deuhn-/, n.1. the act of condensing; the state of being condensed.2. the result of being made more compact or dense.3. reduction of a book, speech, statement, or the like, to a shorter or terser form; abridgment.4. a condensed form: Did you read the whole book or just a condensation?5. a condensed mass.6. (in nontechnical usage) condensate.7. the act or process of reducing a gas or vapor to a liquid or solid form.8. Chem. a reaction between two or more organic molecules leading to the formation of a larger molecule and the elimination of a simple molecule such as water or alcohol.9. Meteorol. the process by which atmospheric water vapor liquefies to form fog, clouds, or the like, or solidifies to form snow or hail.10. Psychoanal. the representation of two or more ideas, memories, feelings, or impulses by one word or image, as in a person's humor, accidental slips, or dreams.11. Physics. the relative amount by which the density of an elastic medium varies from its average value as a sound wave passes through it.[1595-1605; < LL condensation- (s. of condensatio), equiv. to condensat(us) CONDENSATE + -ion- -ION]
* * *Formation of a liquid or solid from its vapour.Condensation usually occurs on a surface that is cooler than the adjacent gas. A substance condenses when the pressure exerted by its vapour exceeds the vapour pressure of its liquid or solid phase at the temperature of the surface where the condensation is to occur. The process causes the release of thermal energy. Condensation occurs on a glass of cold water on a warm, humid day when water vapour in the air condenses to form liquid water on the glass's colder surface. Condensation also accounts for the formation of dew, fog, rain, snow, and clouds.
* * *▪ phase changedeposition of a liquid or a solid from its vapour, generally upon a surface that is cooler than the adjacent gas. A substance condenses when the pressure exerted by its vapour exceeds the vapour pressure of the liquid or solid phase of the substance at the temperature of the surface where condensation (condensation nucleus) occurs. Heat is released when a vapour condenses. Unless this heat is removed, the surface temperature will increase until it is equal to that of the surrounding vapour.If air were free of tiny particles, called aerosols, condensation would only occur when the air was extremely supersaturated with water vapour. In the atmosphere, however, there is an abundant supply of aerosols, which serve as nuclei, called condensation nuclei, on which water vapour may condense. Some are hygroscopic (moisture-attracting), and condensation begins on them when the relative humidity is less than 100 percent, but other nuclei require some supersaturation before condensation begins.In the atmosphere the relative humidity of the air is increased, and condensation results when air temperature is reduced to the dew point or when sufficient water vapour is added to saturate the air. Condensation accounts for the formation of dew, fog, and clouds. For rain to occur, other physical processes are required.
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