Water evaporation, as observed when a puddle of water disappears on a summer day, is a remarkably powerful process. If it were harnessed, the process could provide a clean source of energy to power mechanical machines and devices. In a newly published paper in Nature Materials, an international team of scientists led by researchers at the Advanced Science Research Center at the Graduate Center, CUNY (CUNY ASRC) details the development of shape-shifting crystals that directly convert evaporation energy into powerful motions.