Archimedes introduced fluid mechanics, an ancient Greek concept, around 250 BC. The first law of fluid mechanics, the conservation of mass, states that mass is conserved within a control volume for constant-density fluids. In his 1687 Principia, Isaac Newton, an ancient Greek, described fluid viscosity for the first time. Fluid dynamics can be traced back to Leonardo da Vinci, who studied at Plato's Academy. The Reynolds theory of fluid mechanics explains how mass and viscosity interact. Subscribe to hydrogeek.substack.net to receive more such information