dew, thin film of water that has condensed on the surface of objects near the ground. Dew forms when radiational cooling of these objects during the nighttime hours also cools the shallow layer of overlying air in contact with them, causing the condensation condensation, in physics, change of a substance from the gaseous (vapor) to the liquid state (see states of matter ). Condensation is the reverse of vaporization , or change from liquid to gas.
..... Click the link for more information. of some water vapor. This condensation occurs because the capacity of air to hold water vapor decreases as the air is cooled. The temperature at which condensation begins, for a sample of air with a given water vapor content, is termed the dew point. If a dew point temperature below 32°F; (0°C;) is reached, sublimation occurs, i.e., the water vapor converts directly to frost frost or hoarfrost, ice formed by the condensation of atmospheric water vapor on a surface when the temperature of the surface is below 32°F; (0°C;). In the formation of frost, a gas (water vapor) is changed directly to a solid (see dew ).
..... Click the link for more information. . Should the surface temperature drop below 32°F; after the dew has already collected, the dew may freeze into so-called white dew. Most authorities account for the supply of water vapor as coming from the atmosphere, though some research suggests that it also diffuses up through the soil and then condenses on the ground surface if conditions are favorable. Dew forms most readily on those surfaces that lose heat through radiation most efficiently but are nevertheless insulated from external heat sources. Dew formation is favored by high humidity in the lowest layers of air, which either supplies the moisture or at least inhibits the evaporation of the dew already deposited. Strong winds inhibit dew formation because they mix a larger layer of air, creating a more homogeneous distribution of heat and water vapor; under such circumstances it is unlikely that a sufficiently cool and damp layer of air can form near the ground.

dew

Deposit of water droplets formed at night by the condensation of water vapour from the air onto the surfaces of exposed objects. Dew forms on clear nights, when exposed surfaces lose heat by radiation and are thus usually colder than the air. The cold surface cools the air in its vicinity, and, if the air is humid enough, it may cool below its dew point, the temperature at which water vapour condenses out of the air onto the surface. See also frost.

dew

drops of water condensed on a cool surface, esp at night, from vapour in the air

dew (redirected from dewing)

dew

dew
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