Steam engine

The steam engine is a heat engine that performs mechanical work using steam as its working fluid, an external combustion engine in which the working fluid is separated from the combustion products. Thomas Newcomen built the first commercially successful example around 1712, and James Watt's later improvements to condensing efficiency made the steam engine the power source of the Industrial Revolution, driving factories, steam locomotives and paddle steamers before electric motors and internal combustion engines gradually displaced it in the twentieth century.