What is the function of condensation nuclei in cloud formation? The function of the dew point?

Question

What is the function of condensation nuclei in cloud formation? The function of the dew point?

Answer 1

Condensation nuclei is a fancy name for the microscopically small physical particles (dust, etc.) in the atmosphere that provide the surface area upon which gaseous water vapor can condense into a liquid.  The dew point is the term used to describe the temperature at which that condensation can occur.  Clouds are just collections of small droplets of water floating in the air.  When they get large enough, they fall to the ground as precipitation (rain, snow, sleet and/or hail).

Answer 2

Condensation nuclei provide a surface upon which the cloud droplets form.

I don't think I would say that dew point has a function.  However, it is a measure.  Specifically, it is is the temperature to which a mass of air must be cooled, at constant barometric pressure, for water vapor to condense into water.  That being said, the dew point is important to know in certain situations.  For example, pilots use the dew point to estimate the height of cloud bases and whether or not icing is likely to occur.

Answer 3

The condensation nuceli are very important. Without them, a relative humidity of well over 100% is needed to produce clouds.

The dew point is just the temperature to which a packet of air must be cooled to reach saturation. It is also what starts cloud formation. Once a rising packet of air has reached its dew point- a cloud begins to form.