Answers to Simple Questions We’re Suddenly Dying to Know

Why glue doesn’t stick to the inside of the bottle?

Most glue has water as a solvent which keeps it in a thick, liquid form inside the bottle. It will only become sticky when you squeeze it out of the tube and apply it to a surface. When in contact with the surrounding air, the water present in the glue evaporates, making the glue harden. The only things left are sticky molecules that hold objects together.