BrainStuff Season 3 Episode 18 How Do Erasers Erase?

How Do Erasers Erase?

Have you ever wondered how erasers erase? In this episode of BrainStuff, we delve into this intriguing question and explore the science behind erasing.

Erasers are a common tool used to remove unwanted marks from paper. They are made from a unique substance called rubber, which is known for its ability to remove pencil marks from paper. But how does rubber actually erase pencil marks?

Rubber erasers work by being able to stick to the graphite of pencil lead marks. When you rub an eraser over a pencil mark, the rubber molecules adhere to the graphite molecules. As a result, the graphite particles are pulled away from the paper, effectively erasing the mark.

But why does rubber stick to graphite? To answer this question, we need to delve into the structure of rubber at a molecular level. Rubber is made up of long chains of molecules called polymers. These chains are bonded together in a crisscross pattern, creating a mesh-like structure.

When rubber is heated or put under pressure, the polymers become more flexible and move around freely. This allows rubber to stretch and bend without breaking. When an eraser is rubbed on paper, the heat and pressure cause the rubber to deform and flex. This deformation allows the polymer chains to wrap around the graphite particles, effectively sticking to them.

However, not all erasers are created equal. Some erasers, like hard plastic erasers, work by shaving off the top layer of paper with a small blade. Other erasers, like kneaded erasers, work by absorbing the graphite particles into the rubber. Kneaded erasers are particularly useful for removing fine lines and details, as they can be molded into different shapes and sizes.

Interestingly, rubber erasers don't just work on pencil marks. They can also remove other types of marks, like ink and crayon. This is because ink particles and wax crayon particles are also attracted to the rubber molecules in the same way that graphite is.

Overall, erasers may seem like a simple tool, but there is a lot of science behind their ability to remove unwanted marks. If you've ever wondered how erasers erase, this episode of BrainStuff is sure to satisfy your curiosity.