So have you ever thought about a question, what is an eraser made of? Why can the eraser erase the pencil word easily? And there is no trace after wiping the paper. Today is a long experience. First, let’s take a look at the paper we use for writing. Although these papers are very clean and smooth to the touch, in fact, these papers are made of wood pulp fibers, so if the surface of the paper is magnified dozens of times , You can see that the surface of the paper is actually uneven, with some bulges and ravines left by the wood pulp fibers, but it is precisely because of the structure of the paper surface that the pencil can write marks on the paper. What is going on here?
It turns out that the black pencil core inside the pencil is actually made of graphite and viscous soil. After adding water and stirring, it is sintered, and the graphite pencil core after special treatment has good flexibility. , And adsorptivity, and because it is made of graphite, the color appears black. Due to the strong adhesion of the black pencil lead and the uneven surface of the writing paper, when you are writing, the graphite powder on the pencil lead will be ground down when it comes in contact with the paper, and then adsorbed on the paper. So what you see is the colored pencil written by you.
So, what exactly does the eraser work? Why can the graphite powder with strong adhesion be easily wiped away? The eraser is made of rubber. Unlike the smooth surface of paper, most erasers have a relatively obvious uneven surface. Therefore, if the two rub against each other, the eraser has a stronger friction, so Compared with paper, the eraser wipes off a thin layer of paper by virtue of its stronger friction, peels off the graphite powder from the surface of the paper, and makes the graphite powder adsorb on the eraser, and then a lot of eraser dust is formed, and the paper is Became clean.
But at the beginning, the eraser was made of natural rubber. Because of the high toughness of this eraser, graphite powder was adsorbed on the eraser body when wiping, which caused the paper to become dirty and dirty. The desired effect.
Later, someone discovered that adding sulfur powder to this ancient eraser would reduce the toughness of the rubber and make the overall softer. As a result, the eraser would fall along with the graphite powder that was wiped off when wiping. It is the eraser dust we can see now. With the continuous advancement of technology, the current eraser not only wipes very cleanly, but also has different types of erasers as you use different pencils.
But if it is a water-based pen or a fountain pen, the eraser cannot be erased, because this type of pen will penetrate the ink into the fibers of the paper, and the eraser cannot erase it.