Why does paper turn translucent when wet?


Why does paper turn translucent when wet?


Opaque things (like dry paper) do not let light pass through.

Transparent things (like glass or clean water) do let light pass through and the light stays “ordered” so you can see what’s on the other side.

Translucent things are somewhere in between; they light light through, but disorders it, so you can’t see the things (or at least not as clearly as with transparent things).

Paper becomes translucent because it is made of materials which are good at absorbing water, meaning there is quite a bit of water *right through* the paper once it is wet, giving a pathway for the light to travel. But there is still some plant material which makes up the paper, and the light gets scrambled a bit as it gets past this material so the wet paper isn’t completely see through.