Steam engine

A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force is transformed, by a connecting rod and flywheel, into rotational force for work. Steam engines are external combustion engines, where the working fluid is separated from the combustion products. There are four different parts in a steam engine. The first is a fire where the coal or other fuels burn. The second is a boiler full of water that the fire heats up to make steam. The third part is a cylinder and piston. Steam from the boiler is piped into the cylinder, causing the piston to move first one way then the other. This in and out movement (which is also known as "reciprocating") is used to drive a machine attached to the piston. The final part is a machine attached to the piston. That could be anything from a water pump to a factory machine... or even a giant steam locomotive running up and down a railroad. This is of course a simplified description. In reality, there are hundreds or perhaps even thousands of parts in even the smallest locomotive.