Scientists have made a little drop of metal that’s able to propel itself through liquid and change shape to fit through a narrow passage. It has some fascinating properties that could one day be used to develop new methods for delivering drugs through blood vessels. To make the liquid metal drop, scientists from Tsinghua University in China mixed together gallium, indium and tin. Next, they attached a tiny bit of aluminum to the drop. When dropped into a container of sodium hydroxide or even salt water the aluminum created a chemical reaction with the solution that produced tiny bubbles, which propelled the drop. The propulsion was enhanced by a natural imbalance of electric charges occurring between the front and back of the drop. As long as the aluminum bit was on the back end of the drop, it moved forward. The scientists placed the drop into a container with channels and the drop followed the predesignated path. If the path narrowed, the drop was able to adjust its shape and squeeze through.