Question

Differentiate between:

(i) Precipitation and Condensation

(ii) Absolute humidity and Relative humidity

(iii) Convection rain and Relief rain

(iv) Fog and Mist

Answer 1

(i) Precipitation and Condensation

Basis	Precipitation	Condensation
Meaning	After the condensation of water vapour, the release of moisture is known as precipitation. This may take place in liquid or solid form.	The transformation of water vapour into water is called condensation. Condensation is caused by the loss of heat.
Sequence	Precipitation takes place after condensation.	Condensation takes place before precipitation.
Forms	It may take form of rainfall, snowfall, hailstorms, sleet etc.	It may take form of dew, smog, clouds, fog and mist etc.

(ii) Absolute humidity and Relative humidity

Basis	Absolute Humidity	Relative Humidity
Meaning	The actual amount of the water vapour present in the atmosphere is known as the absolute humidity.	The percentage of moisture present in the atmosphere as compared to its full capacity at a given temperature is known as the relative humidity.
Unit	It is the weight of water vapour per unit volume of air and is expressed in terms of grams per cubic metre.	It is measured in percentage and hence is unit free.

(iii) Convection rain and Relief rain

Basis	Convection Rain	Relief Rain
Meaning	The, air on being heated, becomes light and rises up in convection currents. As it rises, it expands and loses heat and consequently, condensation takes place and cumulous clouds are formed. With thunder and lightening, heavy rainfall takes place but this does not last for long.	When the saturated air mass comes across a mountain, it is forced to ascend and as it rises, it expands; the temperature falls, and the moisture is condensed. In this sort of rain is that the windward slopes receive greater rainfall. After giving rain on the windward side, when these winds reach the other slope, they descend, and their temperature rises. Then their capacity to take in moisture increases and hence, these leeward slopes remain rainless and dry.
Timing	Such rain is common in the summer or in the hotter part of the day.	Such rain is common in winters.
Prevalent	It is very common in the equatorial regions and interior parts of the continents, particularly in the northern hemisphere.	It is very common in terrestrial regions.

(iv) Fog and Mist

Basis	Fog	Mist
Meaning	Fogs are drier than mist.	The mist contains more moisture than the fog.
Prevalent	They are prevalent where warm currents of air come in contact with cold currents.	Mists are frequent over mountains as the warm air rising up the slopes meets a cold surface.
Structure	In mist each nuclei contains a thicker layer of moisture.	Fogs are mini clouds in which condensation takes place around nuclei provided by the dust, smoke, and the salt particles.