Thousands of years ago, some fishermen camped for the night on a sandy beach. After they went to sleep, the hot coals from their campfire glowed far into the night. In the morning one of the men n
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Legends say that this may be the way that people first discovered glass. Glass is formed when sand is mixed with certain chemicals in a very hot fire. Perhaps by accident, all of these materials were
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Over the years glass making improved a great deal. Today glass is so clear like crystal that you can hardly tell it is there. Houses can have many large windows. Some city skyscrapers look as though t
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Of all the objects made of glass, lenses are probably the most important. A lens is a specially curved piece of glass that bends light rays. Lenses make things look either bigger or smaller than they
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