The Invisible Fire Element That Wasn't

Scientists once believed that everything flammable contained a mysterious substance called phlogiston. They thought that when objects burned or rusted, they were actually releasing this hidden fire-like element into the air.

This theory was widely accepted for over a century because it provided a logical way to describe combustion. However, a major problem arose when researchers realized that many substances actually gained weight after burning, implying they absorbed something rather than releasing it. Experiments attempting to prove this theory ultimately paved the way for the discovery of oxygen. It is a fascinating example of how a completely incorrect idea can still lead us toward the truth.