Chris was sitting on the floor with art stuff strewn all around him. He had to make an art project for school. They had just finished learning all about the animal kingdom, and he was put in charge of making a penguin enclosure. He had everything he needed – Thermocol for the base, blue glazed paper to make water, brown paper rocks, penguins that he had made earlier in the day out of out of black and white paper and cute googly eyes, and to put everything together he had with him a big bottle of glue.
This part was tricky. While he loved to do his work on his own, but when it came to sticking things he felt nervous. The glue was just so sticky! It stuck on his hands, then everything else stuck to his hands instead of where it belonged. It all turned messy, always. Once as he unknowingly ran his gloopy hands through his hair, his hair stuck together. Mom had to cut that dried lump of hair later. It looked horrible.
Chris had always wondered to himself – why was the glue so sticky?
Do you also ever wonder why?
Here is why. Everything on earth is made up of molecules. You can think of molecules as tiny dots that when put together make up anything. Adhesives, like everything else, is also made up of molecules – long chains of molecules. But what makes glue different from other things is that glue molecules have a special knack of bonding, that is, attaching themselves with the molecules of the surface they are spread upon. So, when you put glue on any surface, its molecules enter the tiny pores and spaces of the material and bond with the surface. That is the reason whenever you put glue on anything, it instantly sticks to any other thing because the glue’s capacity for molecular bonding.
How strong the glue is depends on how strong bonds it can form with the surface. Adhesives that are used professionally have very strong bonds. Therefore, one has to be very careful in handling them. Ask a carpenter how many times he has stuck his fingers together! Nail polish removers often come handy to remove such type of dried glue. The molecules in the remover have the capacity to break the bond between glue and your fingers.
Did you know?
- Glue has existed for thousands of years. Beeswax and tar were among the earliest form of glue used.
- Caramel that you eat is no less than a glue. The molecules that make up caramel bond with your hand. And thats how it sticks to your hand when you wipe it off your mouth. ;)