Page 4 - Curriculum Visions Dynamic Book

1: Introduction
It is hard to imagine that glass has much to do with the sand on a beach. Yet the rough fragments of sand, which are completely opaque, can be transformed into a material that is completely transparent.
Nature made glass on Earth some four billion years ago. People began to make glass for themselves some 4,000 years ago. Since then people have discovered how truly versatile this material is, made more so by advances in understanding the science of how glass works and how it can be combined with other substances.
The unique nature of glass
Glass is a unique kind of material. Ask anyone what glass is, and they will almost certainly tell you without hesitation that it is a hard substance that you can see through.
Ask them what it is used for, and they might give answers ranging from a lens in their glasses, a windowpane, an optical fibre, to a protective covering on the Space Shuttle.
Crystal
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Glass
(Left and above) The difference between a mineral with regular arrangements of atoms (circles), which can form a ceramic, and glass, with its irregular arrangement of atoms, gives glass its properties such as transparency.