5.1 Steam Engines A steam engine is a heat engine that performs mechanical work using steam as its working fluid Principle of operation for a steam engine When water is boiled to steam at atmosphere pressure, its volume expands about a thousand times If the steam is confined, pressure builds up and the steam tries to expand with great force This force can exerted against a piston or it can work against the blades of a turbine a locomotive powered by the force of steam against pistons. The motion of the pistons is coupled by connecting rods directly to the drive wheels5.1 Steam Engines A steam engine is a heat engine that performs mechanical work using steam as its working fluid. A locomotive powered by the force of steam against pistons. The motion of the pistons is coupled by connecting rods directly to the drive wheels. Principle of operation for a steam engine: • When water is boiled to steam at atmosphere pressure, its volume expands about a thousand times. • If the steam is confined, pressure builds up and the steam tries to expand with great force. • This force can exerted against a piston or it can work against the blades of a turbine