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Post # 1
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Join Date: 20 Sep 2011
Location:  KuwaitPosts: 100 |
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How do erasers remove writing? |
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When you write with a pencil you are rubbing its lead across a surface-usually paper-leaving marks. The marks are really tiny bits of the pencil lead, or graphite, that have stuck to the paper. The surface of an eraser (which is made of rubber or a similar material) is both soft and sticky. When it is dragged across pencil marks, the lead sticks to it. Conveniently, during rubbing, an eraser's surface breaks off in bits, too, which gets rid of the areas where the pencil marks have stuck. The eraser surface remains clean and ready for more work, while the shreds of it that are black with lead can be brushed away. Only special erasers can remove ink, which sinks into paper instead of sticking to its surface. These erasers are made with sand in them to make them more abrasive, because they need to rub away some of the paper in order to remove the ink marks. Erasing crayon marks doesn't work very well because the wax from which crayons are made stick well to paper but not to erasers. Usually trying to erase crayon leaves a smeary mess.
Read more: http://www.answers.com/topic/how-do-erasers-remove-writing#ixzz1ZtOzsInn |
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