Description: Adjustable Speed Single-Cylinder Free Piston Flywheel Stirling Engine Physical Motor Heat Power Generator Engine Model kit. Theory: Similar to internal combustion engine: the burning alcohol lamp provides heat power to make the expansion of gas inside, then the gas molecular internal power increasing and working strongly to the flywheel Adjustable Speed Arange: 200-500RPM (rotate the small hear circle on stand to adjust speed ) With the help of the flywheels, heat energy will convert into mechanical work-The hotter it gets, the faster flywheel rotates! Great educational toy, classroom or laboratory experimental teaching aids, cultivate children'sinterest in physics, more intuitive and easy to understand Great gift for your friends or families. A stirling engine is a heat engine that operated by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, such that there will be a net conversion of heat energy to mechanical work Specification: Fuel: 95% alcohol (alcohol is not included) Cooling Mode: Natural Air Cooling Material: Wooden+Alloy Usage: 1.Placed the Stirling engine in a horizontal position, use your hand to toggle the flywheel to see if it is smooth. 2.Check if every sliding parts is clean. Size Chart: L x W x H: Approx 10*10*10cm/3.94*3.94*3.94inch Package Includes: 1 Stirling Engine Model