Broken circuits could fix themselves using an emergency capsule of liquid metal, invented by researchers at the University of Illinois. As a crack propagates in a circuit, a microcapsule breaks open, spilling liquid metal into the gap and restoring electrical flow. The circuit would only be broken for a few microseconds, just as long as it takes for the capsule to fill in the cracks. During tests, 90 percent of the circuit samples healed to 99 percent of original conductivity, even when only a small amount of microcapsules were used, according to the U of I. Watch White explain the system in the video below.