What is Phlogiston theory?
The '''phlogiston theory''' is an old scientific theory that was used to explain [[fire]] and [[combustion]] before modern [[chemistry]] and the discovery of [[oxygen]]. The concept was put forward in 1667 by [[Johann Joachim Becher]], and many varieties of phlogiston theory were proposed by other 17th- and 18th-century chemists. The theory put forward the belief that there was a fire-like element called phlogiston inside [[fuel]] which escaped when it burned, leaving behind a solid called calx. For a lot of solid fuels like [[coal]], the ash after combustion weighs less than the fuel before, so this seemed logical from the information they had at the time. [[Antoine Lavoisier]] was a major critic of the phlogiston theory. Careful [[experiment]]s that measured the masses of [[Gas|gasses]] showed that the phlogiston theory was wrong. This led to the discovery of [[oxygen]]. However, some scientists continued to believe in phlogiston, and continued to add more complexity to the theory to address the new discoveries. The explanations of phlogiston theorists began to contradict each other, which accelerated the decline of the theory even among scientists who supported it.<ref>{{cite journal|doi=10.1007/s10698-017-9289-0 |title=The development of problems within the phlogiston theories, 1766–1791 |date=2017 |last1=Blumenthal |first1=Geoffrey |last2=Ladyman |first2=James |journal=Foundations of Chemistry |volume=19 |issue=3 |pages=241–280 }}</ref> ==References== {{reflist}} [[Category:History of science]] [[Category:Chemical reactions]] [[Category:Thermodynamics]]