|
Dewpoint
When air of a given temperature and relative humidity is cooled, the
relative humidity increases.
If you have a cold surface, water vapor at a given temperature will
condense on the surface.
The temperature when surface condensation formed is called the dew point,
because at this temperature dew starts to form on surfaces that are not
overgrown.
Condensation is also the reason for the formation of fog and clouds.
Dew in grass however is due to completely different reasons (see
guttation).
Moisture also condenses into materials at a relative humidity below the
dew point, if the material has a moisture content less than the
equilibrium moisture content.
It is then referred to as capillary condensation and is a relatively
slow process compared to surface condensation.
Dew
Dew is water in the form of droplets that appear on thin, exposed
objects in the morning or evening due to frost.
The water form when the warm humid air is cooled
during the night.
The cooled air is not capable of retaining all
the water vapor, but some of the moisture condenses into droplets
deposited for example on walls and cars.
In grass, guttation also contributes to the
formation of dew.
Proximity to waterways promotes the formation of
dew. |
