The heart is a muscular organ roughly the size of your fist. As the heart muscle contracts, it propels the blood out into the vascular system. The heart’s chambers and valves are arranged to direct ...

[TheBackyardScientist] decided to build a machine to create the gas rings, and it’s quite interesting to see them go through several iterations before settling on a voice coil based poppet valve ...

The engine was simple, with a ball valve that admitted air into the cylinder when a spring mounted to the top of the piston popped it out of the way. That spring has always bothered [Tom], though ...