Which scientist discovered the law of conservation of mass?

Which scientist discovered the law of conservation of mass? Antoine Lavoisier is the scientist most commonly credited with establishing the law of conservation of mass.

In the late 18th century, Lavoisier transformed chemistry by treating measurement as central to experimentation. He weighed reactants and products carefully, including gases that earlier investigators often ignored. His work showed that in a closed system, the total mass remains constant during a chemical reaction, even though substances may change into new compounds.

The principle helped replace the older phlogiston theory of combustion. Lavoisier demonstrated that burning involves combination with oxygen, and his quantitative approach supported the modern practice of balancing chemical equations. The familiar summary “nothing is lost, nothing is created, everything is transformed” is associated with his formulation.

Lavoisier was not necessarily the first person to express a conservation idea. Mikhail Lomonosov had stated and experimentally supported a similar principle earlier, in the 18th century. Nevertheless, Lavoisier's precise, influential experiments established the law within modern chemistry, making Antoine Lavoisier the canonical answer to this quiz question. He also helped standardize chemical nomenclature and identified oxygen's role in combustion.