Rob writes – “One of the simplest forms of an engine is known as a Hero’s engine. A Hero’s engine uses heat from a fire to create steam. That steam is then forced to exit through a pipe or jet, which causes the entire apparatus to spin. I did a little research and found that a soda can is a terrific platform for building a Hero’s engine. I couldn’t resist trying such a cheap experiment…” – Link.
Building a simple Hero’s Engine from a soda can