Why do liquids evaporate below their boiling temperature.

1.31K views

Water’s boiling temperature is 100C or 212F, when you spill some on concrete or leave a cup of water outside, it disappears without it reaching 100C even if it is in the shade. The water from the ocean also evaporates, but it is not boiling. This happens with other liquids to such as isopropyl alcohol, or gasoline.

How does this happen?

In: Chemistry

7 Answers

Anonymous 0 Comments

There are already some good descriptions in many comments. What I’d emphasize: evaporation always happens (as your question noted). Boiling is simply a quick evaporation process, that happens when the vapor pressure reaches that of the atmosphere. (At which point vapor can suddenly form inside the liquid, not just on the outer surface.) But this is not of a requirement for the slower evaporation that occurs at lower temperatures.

Fun fact: even [ice evaporates](https://en.wikipedia.org/wiki/Freeze-drying)! So frozen liquid would also “disappear” eventually, if exposed to dry enough atmosphere. That is, liquids evaporate (albeit very slowly) even below their freezing temperature.

Even funnier fact: you can [boil water at zero Celsius](https://en.wikipedia.org/wiki/Triple_point#/media/File:Water-triple-point-20210210.gif).

You are viewing 1 out of 7 answers, click here to view all answers.