Power this engine with a cup of steaming hot coffee or set it on a plate of ice chips to see it run in the opposite direction. A favorite of engineers and techies all over the world, this Stirling engine has been used for educational demonstrations from middle school science classes to Harvard thermodynamics courses.

The MM-1 spins approximately 250 rpm on hot coffee and 100 rpm on ice in a warm room. No assembly required. Mug not included.