As a kid, arts and crafts were one of my favorite hobbies, and still is now. Most craft glue, Elmer’s brand especially, comes in a thick white color, and if you have never used glue before you would think it would dry the same color. BUT NO! Glue has properties in it that make it dry clear, so crafts and other projects don’t seem messy. This is great an all, but HOW does this color transformation happen? Craft and school glue are essentially made of Polyvinyl acetate (PVA), a powdery substance that doesn’t mix well with water, which turns into other stages, forming the hardened and fastened glue.
A science blogger, “John The Math Guy” explains the breakdown of wet glue and why it forms to the clearer hard state to hold objects together. The reason glue looks milky, as he puts it, is because the PVA is mixed with water which causes it to be wet. Since the water is the part that is wet and therefore will dry, that causes the PVA to turn clear, since it has nothing keeping it wet anymore. The water evaporates, which leaves only PVA plastic leftover, which is clear.
So it isn’t as complicated as I thought- It just has to do with water evaporating and leaving behind the clear PVA particles.