If you exhale clouds, does that only have to do with the fact that it is very cold?

Answer

Dear Monica,

the exhalation of clouds is an example of condensation. To understand condensation, you first need to know that water can be “dissolved” in air. Usually an air contains an amount of water vapor, consisting of particles of water. The warmer the air, the more water vapor it can hold (this is called absolute humidity). Relative humidity also exists. This is the ratio of the actual humidity of the air to the maximum. Air with a relative humidity of 100% can therefore no longer absorb extra water vapour. The extra water vapor you put in will precipitate (condense). Because warm air can contain more water vapor than cold air, cold air, with a relative moisture content of 100%, will have a lower moisture content when you heat it up (e.g. 80%; then 20% water vapor can be added). Conversely: if you cool “wet” air, part of the water vapor will precipitate because the (cold) air can contain a maximum of 100% relative humidity.

What happens when you exhale in cold air? Your breath contains a lot of water vapor and is warm. If this breath ends up in the ambient air, it is quickly cooled and part of the water vapor will condense, which you can see as clouds. This is also possible in the summer, but only if the air is cold enough. If you don’t take your breath but steam (with a relative humidity of 100%), you will always see this, because the temperature is always warmer than the ambient air and therefore some water vapor will always condense.

Hopefully it’s clear enough.

Bart