... machine, or is it something more than that? Well, the answer is it's more than that. The Second Law of ... falls over. The felt head, soaked in the water from the cup, cools the methylene chloride, and it drains back to the bottom. The bird rights itself, and it ... Temperature differentials drive the motor. That energy comes from the environment - from the sun. Is it efficient? Hardly, but it's still very ...