Capillary condensation

When you put a straw in a drink and the drink goes up a little bit inside the straw, that's kind of like capillary condensation.

Capillary condensation happens when there is a substance (like water) in tiny spaces (like tubes or pores) that are really, really narrow. The substance gets stuck in the spaces because it's too big to get through, like you can't fit a big toy truck through a small hole in the wall.

Now, imagine you have a bunch of tiny straws, all close together. If you put them in a glass of water, some of the water will go up into the straws because of capillary condensation. This happens because the water likes to stick to the inside walls of the straws, a bit like how you put stickers on things.

So, sometimes capillary condensation can make things like rocks, concrete or soil very wet. This can be really important for things like plants and trees, which need water to grow.