Chapter 31, Problem 4RQ

What does saturation point have to do with dew point?

To determine

The effect of saturation point on dew point.

Answer to Problem 4RQ

When air starts to cool at saturation point condensation occurs.

Explanation of Solution

The saturation point is the point at which air reaches its saturation limit, which means air contains the most quantity of water vapor in it. The value of relative humidity, which represents the moisture or water vapor content in the air at its peak, means $100\%$.

At that point, the dew point of the air represents the saturation temperature of the air; when the air starts to lose heat and cool down, condensation will occur, and droplets formed.

Conclusion:

Therefore, as air starts to cool at saturation point condensation occurs.