At first this would only run beautifully for a very short bit and then stop, as if it couldn’t dissipate the heat and thus no thermal gradient. But maybe by allowing the upper piston more freedom, the slight leak of air around the test tube was increased enough to refresh the system with cooling air. The piston on the bottom is upturned and bounces off the bottom of the red silicone stopper.
The faint blue cap on the top of the upper test tube is a Silicone Tattoo Ink Cup and the springy band is a strand of Dental Orthodontic Elastic Rubber Power Chain Braces Band all bought on eBay.
#Free #Test #Tube #Piston #Stirling #Engine