Scale: Not to scale. A diagrammatic model in a glazed wooden display case made to show how a steam engine converts reciprocating motion into rotary motion. The depicted engine is shown as a sectional cut-away and when operated, the downward force of the piston causes a three bladed propeller, linked to the piston by the piston rod, to turn. The engine has been painted a light grey colour and the cut-away face of the cylinder and piston, together with the propeller, is painted red. It is mounted against the rear of the case along with an explanatory label. The front of the case is glazed and there is deep black painted wooden frame. The model is operated by electricity and has an accompanying plug and cable (disconnected).