What is the difference between dew point and saturation?

What is the difference between dew point and saturation?

• A. Dew point is the temperature to which air must be cooled for condensation to begin; saturation is the maximum water vapor a given temperature can hold.
• B. Dew point is the current air temperature.
• C. Saturation is the amount of water vapor currently in the air.
• D. Dew point equals the current air temperature.

Answer: (A)

Dew point is a temperature, while saturation is a limit on how much water vapor air can hold at a given temperature. The dew point tells you the temperature air must be cooled to for condensation to begin, given the current amount of moisture. When air is cooled to that temperature at constant moisture, it becomes saturated and condensation starts—think dew, fog, or clouds forming. Saturation describes the maximum water vapor content possible at that temperature (and pressure). If the air has more water vapor than this limit, or if it is cooled further, the excess vapor condenses. At saturation, relative humidity is 100%. So dew point is about the threshold temperature for condensation, whereas saturation is about the capacity of air to hold water vapor at a specific temperature.

Dew point is a temperature, while saturation is a limit on how much water vapor air can hold at a given temperature. The dew point tells you the temperature air must be cooled to for condensation to begin, given the current amount of moisture. When air is cooled to that temperature at constant moisture, it becomes saturated and condensation starts—think dew, fog, or clouds forming.

Saturation describes the maximum water vapor content possible at that temperature (and pressure). If the air has more water vapor than this limit, or if it is cooled further, the excess vapor condenses. At saturation, relative humidity is 100%.

So dew point is about the threshold temperature for condensation, whereas saturation is about the capacity of air to hold water vapor at a specific temperature.