Power of Fire
Civilization would not be possible without fire. Human beings have known how to control fire for almost 1.5 million years. But for many thousands of years after that, people still found it difficult to start a fire. One method they used was to strike one hard mineral against another to make sparks. A second method was to twirl one piece of wood against another until the wood heated up to its ignition point.
Fire is very useful. Campfires kept people warm and scared off wild animals. Fire lit the way at night and also cooked food. Later people set fires to clear land for farming. They used fire to make pottery from clay, to shape metals. Fire is used in many factories to operate furnaces or heat boilers. In a steel mill it is used to melt the materials that go into making steel.
However, fire is dangerous. It always must be used very carefully.
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