The nature of fire has puzzled the human mind since ancient times. What is fire? Which forces mold its unpredictable behavior? These questions presented a major challenge because fire is an extremely complex natural phenomenon. Ancient humans thought fire had a mind of its own and treated it as a living entity.

By the early eighteenth century, philosophers had concluded that fire was a substance. In 1772, however, Antoine Lavoisier, the father of modern chemistry, showed with simple experiments that fire is not a substance but the product of a chemical reaction that requires oxygen and releases heat and light. The French chemist and others went on to prove that fire has definite physical and chemical properties, and these characteristics are the same whether it is a flame burning a birthday candle or one-hundred-foot-high flames consuming a forest.

The Fire Triangle

Fire is the result...