What is Steam engine?
[[File:Engine House (3452966818).jpg|thumb|right|200px|Full scale working replica of 1712 [[Thomas Newcomen]] engine for pumping water from mines on the estates of Lord Dudley. Black Country Living Museum]] [[File:Puffing Billy side Science Museum London.jpg|thumb|right|200px|Earliest surviving [[locomotive]]: Puffing Billy at the [[Science Museum (London)|Science Museum]]]] [[File:Cathedral of Sewage - geograph.org.uk - 676706.jpg|thumb|right|200px|This huge building housed the four largest beam engines in Britain. They were used for moving [[sewage]] at Crossness, [[London Borough of Bexley|Bexley]]]] [[File:Old bess steam engine 1777.jpg|thumb|right|200px|Old Bess: Watt's beam engine, 1777, built by Boulton and Watt. The engine was used to raise water. Constant water was needed because a water wheel was used to drive the machinery in Boulton's Soho Manufactory in [[Birmingham]]]] A '''steam engine''' is an [[engine]] that uses [[steam]] from boiling water to make it move. The steam pushes on the engine parts to make them move. Steam engines can power many kinds of [[machines]] including [[vehicle]]s and [[electric generator]]s. Steam engines were used in mine pumps starting in the early 1700s century and were much improved by [[James Watt]] in the 1770s. They were very important during the [[industrial revolution]] where they replaced horses, [[windmill]]s and [[watermill]]s to work machines. The first steam engines were piston engines. The steam pressure pushed on a [[piston]] which made it move along a cylinder and so they had a ''reciprocal'' (back-and-forth) motion. This could move a pump directly or work a crank to turn a wheel and work a machine. They operated at low [[pressure]] and had to be very big to make a lot of power. Steam engines were used in [[factory|factories]] to work machines and in mines to move [[pump]]s. Later smaller engines were built that could move [[railway]] [[locomotive]]s and [[steam boat]]s. The steam to power a steam engine is made in a boiler that heats water to make s