Wet bulb temperature & Dew point

[sharjeel]

What is the difference between wet bulb temperature and dew point of a vapor? In case of moisture in air how can each term be used to calculate quantity of moisture in air. Are they one and the same thing? If yes than is there any correlation that relates both of them?

[Imran.Idris]

Wet Bulb Temperature is the temperature attained by a mass of liquid kept in a flowing stream of a gas under adiabatic /non equilibrium conditions. It can be explained in a simple way by saying that when a cotton wick soaked in water is wrapped around bulb of a thermometer and placed in air under a shade, the temperature attained by wick in such conditions (this temperature can be equal or below the actual ambient temperature or dry bulb temperature) is called wet bulb temperature. This is direct indication of moisture content of air, the more the air nearer to its saturation point the more closer would its wet bulb and dry dry bulb temperatures be.
Whereas dew point is the temperature at which vapors of a liquid would start condensing in a gaseous stream if temperature of this gaseous stream is further reduced beyond this temperature.
Wet bulb and dew point can be different for a mixture of a gas and vapor. They are equal when gas in fully saturated with condensing vapor.
Based upon wet bulb, dry bulb and dew point of air, psychrometric charts are developed which are used to measure '%', 'absolute' and 'Relative' humidity of air.
Hope I answered the question.

[sharjeel]

Thanks dear for your elaborative response..
But one thing that really strikes me again and again is that how can we correlate these two properties together?

[Imran.Idris]

Dear forum member, psychrometric chart very well serve the purpose if you observe the it closely.
For example say you have measured dry bulb and wet bulb temperatures of air and it come out to be 30C and 20C respectively. Now locating the point on the psychrometric chart where dry bulb and wet bulb temperature line with values 30 C and 20C intersect each other, you can find out three things. 1)Absolute humidity = 0.011 gm of moisture / gm of dry air, 2) Relative humidity = 40%, and the third thing is 3) dew point of given air (with 0.011 gm of moisture / gm of dry air if you extend the line to 100% humidity, the corresponding dry bulb temperature would give dew point of the air) is 16C.
i hope this makes sense to you? Correct me if I am wrong.
Regards,
Imran

[sharjeel]

Thanks dear for further explanation