http://www.popularmechanics.com/science/energy/a16045/evaporation-engine/It might not look like much, but this plastic box is a fully functioning engine—and one that does something no other engine has ever done before. Pulling energy seemingly out of thin air, it harvests power from the ambient evaporation of room-temperature water. No kidding. A team of bioengineers led by Ozgur Sahin at Columbia University have just created the world's first evaporation-driven engine, which they report today in the journal Nature Communications. Using nothing more than a puddle of resting water, the engine, which measures less than four inches on each side, can power LED lights and even drive a miniature car. Better yet, Sahin says, the engine costs less than $5 to build.
