water droplets that condense from the air onto cool surfaces are called frost.
water droplets that condense from the air onto cool surfaces are called frost.
water droplets that condense from the air onto cool surfaces are called?
frost
the main products of hydrocarbon fuel combustion are carbon dioxide and water vapor. at high altitudes this water vapor emerges into a cold environment, and the local increase in water vapor can raise the relative humidity of the air past saturation point. the vapor then condenses into tiny water droplets which freeze if the temperature is low enough. these millions of tiny water droplets and/or ice crystals form the contrails. the time taken for the vapor to cool enough to condense accounts for the contrail forming some distance behind the aircraft. at high altitudes, supercooled water vapor requires a trigger to encourage deposition or condensation. the exhaust particles in the aircraft's exhaust act as this trigger, causing the trapped vapor to condense rapidly. exhaust contrails usually form at high altitudes; usually above , where the air temperature is below . they can also form closer to the ground when the air is cold and moist.
contrail
cumulus clouds can be composed of ice crystals, water droplets, supercooled water droplets, or a mixture of them. the water droplets form when water vapor condenses on the nuclei, and they may then coalesce into larger and larger droplets. in temperate regions, the cloud bases studied ranged from above ground level. these clouds were normally above , and the concentration of droplets ranged from 23 to 1300 droplets per cubic centimeter (380 to 21,300 droplets per cubic inch). this data was taken from growing isolated cumulus clouds that were not precipitating. the droplets were very small, ranging down to around 5 micrometers in diameter. although smaller droplets may have been present, the measurements were not sensitive enough to detect them. the smallest droplets were found in the lower portions of the clouds, with the percentage of large droplets (around 20 to 30 micrometers) rising dramatically in the upper regions of the cloud. the droplet size distribution was slightly bimodal in nature, with peaks at the small and large droplet sizes and a slight trough in the intermediate size range. the skew was roughly neutral. furthermore, large droplet size is roughly inversely proportional to the droplet concentration per unit volume of air. in places, cumulus clouds can have "holes" where there are no water droplets. these can occur when winds tear the cloud and incorporate the environmental air or when strong downdrafts evaporate the water.
cumulus cloud