Academic Reading
The story of glass
AGlass is made mainly from sand, which is heated until it melts and then cooled so quickly that it does not form crystals. Natural glass has existed for millions of years, created where lightning strikes sand or where volcanoes produce a black glass called obsidian.
BPeople learned to make glass thousands of years ago, but it was the Romans who first produced it in large quantities and discovered how to blow it into shapes. Today glass is everywhere, from windows and bottles to the fine optical fibres that carry information around the world.