The formation of dew depends on various conditions such as Cloudless Clear Sky, Still air, Amount of water vapour in the air, Presence of good emitters and poor conductors of heat, and Presence of objects near the surface.
After going through this lesson, you will be able to understand how is dew formed.
How is Dew formed?
Normally water vapour in the air is unsaturated. At night the surface cools by radiating heat. As a result, the atmosphere near the surface also cools.
The amount of water vapour present in the air for cooling does not change. As a result, the cooling air then moves from the unsaturated state to the saturated state by the aforementioned water vapour.
The temperature of the air gradually decreases, eventually reaching a point where the air becomes saturated with water vapour present in it.
As soon as the temperature of the air decreases a little, some amount of water vapour condenses and takes the form of water droplets. This condensed water vapour harbours the dust particles present in the air and forms water droplets. These water droplets are called dew.
What is Dew Point?
The temperature at which a certain amount of air is saturated with water vapour present in it is called the dew point of that air.
Also, Read
What is Condensation?
What is Evaporation?
The Boiling Point of Liquids
