Imagine a world without fire. There would be no cooked food, no artificial light, and no way of keeping warm in a cool climate. Fire can be dangerous, but over thousands of years we have learned to tame it. We use it to make pottery glass, and metals. It enabled us to invent the steam engine the internal combustion engine, and the rocket Where would we be without it? Excerpts from Experts: Fire depends on three things: oxygen, heat, and fuel-the "fire...