Antoine+Lavoisier+and+Phlogisten


 * Antoine-Laurent Lavoisier disproves the Phlogiston Theory **
 * What happened? **

In the late 17th century an alchemist named JJ Becher made the first attempt to explain why certain objects burn. Since the beginning of time, people have known that wood burns and stone does not. Exactly why this is had eluded us. Becher proposed the existence of an invisible substance called phlogiston. Things rich in phlogiston were more likely to burn and be 'dephlogisticated'. Flammable objects were full of phlogiston and unburnable objects were phlogiston poor. When an object burned, it lost its phlogiston. This explanation explained why a log lost mass when it burned.

Unfortunately for this theory Robert Boyle was able, through careful measurement of the mass of the products and reactants, to show that magnesium actually gained mass when it burned. Since it gained mass, this meant it wasn't losing phlogiston when it burned. Proponents of the phlogiston theory replied out of desperation that phlogiston must sometimes have negative mass, a theory that was finally proven by the work of the brilliant French chemist, Antoine Lavoisier.

Laviosier was able to carefully control the burning of cotton wool. By encapsulating the reaction in glass containers and carefully weighing the ingredients before and after burning he was able to precisely measure how the mass of the system changed. What he was able to prove was that the mass of the ingredients didn't change even if a substance was burned. Using these measurements he was able to prove the existence of a gas in the air that was required for objects to burn. He named this external gas 'oxygen'. The existence of oxygen was the final nail in the coffin of the phlogiston theory. He also came up with a little thing I like to call __The Law of Conservation of Mass__.




 * Science is... **

Able to change when better measurements are made. Theories are based on measurements. The better the measurement, the better the theory. Antoine Lavoisier contributed many things to science, perhaps his greatest contribution was the fact that he carefully measured __and recorded__ his measurements. He was one of the first people to take science from the realm of theory to actual experimentation.


 * References **

Phlogiston theory. (2013, April 26). In Wikipedia, The Free Encyclopedia. Retrieved 17:23, May 16, 2013, from []