Steam engine

Steam engine

A steam engine is any engine that is operated by the energy of expanding steam. The steam may be used to power an engine by spinning a turbine or by pushing pistons. Huge turbines drive electric generators and giant ships. Piston steam engines power large pile drivers. In some countries, locomotives with piston steam engines are still used to pull railroad trains. In the United States, diesel locomotives pull most trains.

The development of the steam engine in the 1700's made modern industry possible. Until then, people had to depend on the power of their own muscles or on animal, wind, and water power. One steam engine could do the work of many horses. It could supply the power needed to run all the machines in a factory. A steam locomotive could haul heavy loads of freight great distances in a single day. Steamships provided safe, fast, dependable water transportation.

Excerpt adapted from the "Steam engine" article, The World Book Encyclopedia, © 1999.