What is dew point?

What is dew point?

• A. The temperature at which water condenses from vapor
• B. The temperature at which air becomes saturated and can hold no more water
• C. The temperature at which air can hold more water
• D. The temperature at which water boils

Answer: (C)

Dew point is about humidity and saturation. Relative humidity tells you how close the air is to holding all the water vapor it can at a given temperature. The dew point is the temperature to which air must be cooled (at the same pressure) for it to become fully saturated—when it can hold no more water vapor. At that point, any further cooling causes water vapor to condense into liquid. That makes the statement describing the dew point as the temperature at which air becomes saturated and can hold no more water the best fit. The idea that air can hold more water describes unsaturated conditions, and the boiling point of water is a different concept entirely.

Dew point is about humidity and saturation. Relative humidity tells you how close the air is to holding all the water vapor it can at a given temperature. The dew point is the temperature to which air must be cooled (at the same pressure) for it to become fully saturated—when it can hold no more water vapor. At that point, any further cooling causes water vapor to condense into liquid. That makes the statement describing the dew point as the temperature at which air becomes saturated and can hold no more water the best fit. The idea that air can hold more water describes unsaturated conditions, and the boiling point of water is a different concept entirely.