Reciprocating engine

A reciprocating engine is a machine that can turn fuel into motion. It is like a big toy car engine that makes a toy car move.

Think about the way your arms and legs move when you run. That's how a reciprocating engine works! A piston (which is kind of like your leg) moves up and down inside a cylinder (which is like a toy car's steering wheel) in a back and forth motion. This movement causes the fuel and air to mix and combust, which makes a small explosion. That explosion pushes the piston down and causes the energy to go into moving other parts of the engine, like the wheels.

There are lots of different types of reciprocating engines, but they all work in basically the same way - by moving a piston back and forth inside a cylinder to create energy that moves other parts of the engine. Reciprocating engines are found in cars, airplanes, and lots of other machines.