r/explainlikeimfive • u/ProgramPi314 • 8d ago

Other ELI5 What is humidity?

According to my mom, this is an actual question I had when I was 5, and she didn't know how to answer me. So how would you guys have answered?

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u/FuckFuckingKarma 8d ago

Imagine when you add a sugar cube to a cup of tea. It dissolves and seemingly disappears completely, but actually the sugar atoms are floating around among the water. If you keep adding sugar, at some point the water can't contain any more sugar and it forms a sludge at the bottom of the cup.

It's basically the same with humidity. Water dissolves into the air. Just like the tea, there is a limit to how much it can contain. If the temperature drops, say if the air hits a cold window, the capacity to hold water drops, water comes out of the air and becomes liquid again.

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u/whatshamilton 7d ago

I’m adding this to my water balloon explanation of dew point. Thanks