Writing something in pencil then being able to undo your mistakes with just a few seconds of rubbing your eraser against the paper is, in fact, NOT magic! Read to find out the history behind erasers and how they work!
The Eraser's History
In 1770, Edward Naime is credited to have invented the eraser. During the 18th century, people used rolled up pieces of white bread to get rid of unwanted pencil marks, and Naime was said to have mistakenly used rubber instead of the usual bread piece, and found that it worked even better and was more efficient than bread. Naime began selling these pieces of rubber to use as erasers, which is why they were originally called "rubber", and in some places they are still called "rubber" even to this day!
Later on in 1839, Charles Goodyear began treating the eraser with sulfur, a process called vulcanization, which prevented the erasers from going bad, making them extremely popular and becoming common all over the world.
How We Use Them Today
In current times, erasers are something we often use every single day, and are pretty much an essential supply throughout school. Even though we use them all day everyday to undo our mistakes; have you ever thought about how they actually work?
Firstly, we should understand what erasers are getting rid of: pencil lead. Pencil lead is actually not made out of lead metal, but graphite mineral. When we rub the graphite in our pencil on a piece of paper, the particles of the mineral are rubbing off and sticking to the fibers of the paper. Therefore, this graphite isn't permanently stuck on the paper, as it is just mineral that has rubbed off.
On the other hand, the main component of erasers is rubber (however, sometimes other materials such as plastic are also used to make erasers, which is why some erasers differ in texture). The eraser is a combination of rubber and sulfur, which preserves the eraser and allows it to be used for a longer period of time. Additionally, a softener is added (e.g. vegetable oil) which is what allows erasers to be flexible, along with abrasives. Lastly, dyes could be added to them to give them a particular color.
When erasers are rubbed against the graphite that was rubbed off the lead of a pencil, the particles of graphite are loosened by the abrasives in the eraser, and sticks to the rubber. The act of rubbing the eraser against the paper produces friction, which produces heat that increases the stickiness between the rubber and graphite, allowing them to combine, which is the crumbly substance one sees after using an eraser.
There are many types of erasers that can be used for different purposes, all depending on their properties and ingredients. For instance, specialized erasers for art are made out of gum and there are even erasers that can be kneaded and have consistencies like putty! The most common ones that you probably use are rubber erasers, and they are sufficient for everyday use in school.
Thank you for reading, we hope you learned something new!
References:
Helmenstine, Anne Marie. “Learn the Science Behind How Pencil Erasers Work.” ThoughtCo, 11 Feb. 2019, www.thoughtco.com/how-do-pencil-erasers-work-604298.
“How Does an Eraser Work?” Wonderopolis, 14 Nov. 2019, www.wonderopolis.org/wonder/how-does-an-eraser-work.
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