Many thousands of years ago, people began to find ways of changing the simple materials they found around them into more useful forms that could help them survive in a hostile world. Soft clay was available everywhere and easy to shape, but it was fragile. Transformed by fire, it became the hard, waterproof body of a cooking pot or storage jar. Even common sand can be transformed by heating it with other substances to make the smooth, transparent material called glass. Other rocks yield strong, tough metals when heated with the right materials. All of these processes require energy, often in the form of heat. And all of them are still in use today, although they now take place on a huge scale, using much more energy than in the past.
Grecian crafts
The bottom of this ancient Greek cup was decorated by scraping away a black coating to reveal the red clay underneath. Often leather was fashioned into sturdy sandals.
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