If amount condensation exceeds amount evaporation at 65 deg. based on amount watervapor in air what is the 65?

Question

Here;s the full question...sorry:

If the amount of condensation would exeed the amount of evaporation at 65 degrees F, based on the amount of water vapor in the air, what does 65 degrees F represent?

Thanks.

Answer 1

I am not sure I understand your question but here is something that might help you:

59 F (15 C) is the average temperature on earth. At that temperature, the maximum humidity the air can sustain is 14 grams water per cubic meter. When that happens, the air is said to be 100% saturated and a hygrometer will show 100% relative humidity. The absolute humidity is 14 grams.

When the air is colder, it can contain less water. When the air cools down either by rising or by dissipating heat during the night, if the air is 100% saturated, moisture has to condensate as water droplets. That is called the due point.

In the past, seafarers were using the wet & dry bulb thermometer. It consists of two similar thermometers only that one is in wet cotton and allowed to evaporate. Since evaporation requires energy in form of heat, that thermometer is lower than the other one. The difference between the two is called the spread - also the difference between the temperature and the dew point temperature. When the spread is nil or very small, the air is saturated and fog may be expected. If the spread is large, then the air is very dry.

In aviation, you can estimate the ceiling of the clouds by knowing the temperature on the surface and the dew point temperature. The air cools down by about 2 degrees Celsius per thousand feet of altitude. If say the surface temperature is 15 C and the dew point is 11 C, the spread is 4 C and the ceiling can be expected at 2,000 feet above the ground.

I hope it helps.