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Eraser (it is also called rubber band) has three important qualities that help him to remove traces of pencil on paper:

1. The eraser material is such that the graphite particles (thickness from 20 to 10 microns) stick to it during the friction of the eraser on paper. Because this creates electrostatic voltage which allows the particles of rubber bands to fasten the graphite particles.

2. The material from which made the eraser crumbling. This is to ensure that small particles eraser was separated from him during erase. Thanks to its erasing surface is constantly changing and being updated. Dried and poor gum (which is not erased used layer) stain the paper as stuck and does not come with the rubber layer graphite smeared on the paper.

3. And even erasers have a weak abrasive, i.e. abrasive properties to remove small particles of the paper, together with traces of pencil.

Modern erasers are made of rubber. Before the advent of rubber to erase the graphite from the paper used bread crumbs. In 1736, the French traveler and Explorer Charles Marie de La Condamine was brought from South America so-called "Indian rubber" - rubber, which were subsequently used to erase pencil lines. Unfortunately, like bread, the eraser was short-lived and quickly rot. But this problem was solved by Charles Goodyear in 1839, opening the process of vulcanization reaction in which the molecules of the rubber is stitched together into a single mesh. And attach the rubber band to the end of a pencil for the first time thought of American Hyman Lipman in 1858.



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Total votes: 104

Your comments:

2014-04-08 18:20:10
all clear thank you
2014-03-19 17:26:14
cool thanks
2013-05-06 19:04:02
thank you all cool and clear
2013-05-06 18:36:56
I understood everything
Jura, expert
2012-05-30 05:32:35
a bit of zakonchino. by the way the eraser is used in the polishing of diamonds, crystals, emeralds, and many other precious stones and fossils
2012-01-31 23:42:39
Well, so-so
2011-11-26 00:18:58
thank you, I understood everything
2011-01-31 12:22:56
Just super*
2011-01-31 12:20:59
Anything correctly!

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