How it Works: A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, resulting in a net conversion of heat energy into mechanical work. A Great Explanation: Teachers can make the explanation process much more straightforward, helping students better understand the principle. Safe Operation: Runs safely on the top of a cup of hot water; no open flame or alcohol lamp required, making it suitable for children. Operating Requirement: Requires a minimum temperature difference of 25°C between the bottom of the device and the surrounding environment to start. Easy to Use: Simply give the wheel a gentle spin to start operation. Considerate Design: Features a precision frosted plunger to help prevent leakage and reduce wear. Note: If there is excessive friction between the flywheel and support, a small amount of graphite dry lubricant can be used to reduce noise. Do not use oil, as it may attract dirt. Low Temperature Stirling Engine Model DIY Kit Principle of Operation: Heating Expansion / Cold Compression Speed: 180rpm (max.) Note: Children under 12 years old should be supervised by an adult when using this product. Color: Silver + Gold Material: Metal Package Contents: 1 x Low Temperature Stirling Engine Model DIY Kit 1 x Instruction Manual (bilingual Chinese and English) Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the image and the actual product. Measurement may vary by +/- 1-3cm.