Tiny Water Droplets Self-Propel on Sizzling Surfaces

Many cooks have experienced this--sprinkle a few drops of water on a searing hot skillet, and watch them roll around like a couple of glass beads. Scientists had previously thought that this phenomenon is solely due to the cushions of steam that form underneath the droplets, but now researchers find these drops also propel themselves, with the churning fluid inside them acting like engines. This discovery could lead to new kinds of self-propelled devices, they add. The successive states of a wat...