You remember those art and craft classes in school? Glue used to be the most important thing there. Well, even today it is being largely used, though surely it has modified over the years.
Glue has the sticky polymers that hold things together and this process is called mechanical adhesion.
But, have you ever wondered why it doesn’t stick inside the glue bottle?
We thought about it and brought you the reason.
The glue that we use to paste things doesn’t stick inside its bottle because it needs air to evaporate water and get sticky. Due to the less air present inside the bottle, it does not stick inside.
There are some type of glues which needs special chemicals other than those present in air to get sticky; for these type of glues, even if you leave the cap off, it won’t stick inside the bottle.
Also, there are glues that contain special solvents that keep the molecules of the glue away from each other. The solvent can evaporate in a half empty bottle but because of the limited space, it doesn’t and hence the glue does not stick inside its bottle!