Condensation and Vapour Pressure
So last time we talked about condensation and relative humidity, how this is expressed as a proportion of how much moisture air can hold at a given temperature, and how 'dew point' temperature, is the exact temperature where vapour condenses back into a liquid (100% RH).
By James Hockey
.avif)
Today let's think about vapour pressure. This is actual quantity of moisture in the air.
Simplistically therefore, high vapour pressure = wet air, low vapour pressure = dry air.
The thing to understand about differential vapour pressures, is that they will seek to equalise.
What does this mean? Example:
Two sealed rooms with a wall and door separating them. One has a shower in it which has been running and it's steamy/humid, i.e. high vapour pressure. The other room has a dehumidifier running and it's very dry / low vapour pressure.
When the door is opened between the rooms, what happens? Does each level of vapour stay exactly the same in each room?
No.
