Making an invisible electric wire: Guiding electricity with sound

Electric sparks are used for welding, powering electronics, killing germs or for igniting the fuel in some car engines. Despite their usefulness, they are hard to control in open space, they split into chaotic branches that tend to go towards the closest metallic objects. A recent study uncovers a way of transporting electricity through air by ultrasonic waves. The level of control of the electric sparks allows to guide the spark around obstacles, or to make it hit specific spots, even into non-conductive materials.