On a laboratory bench in Cambridge, Massachusetts, a stack of polished cylinders of black-coloured concrete sit bathed in liquid and entwined in cables. To a casual observer, they aren’t doing much. But then Damian Stefaniuk flicks a switch. The blocks of human-made rock are wired up to an LED – and the bulb flickers into life.
“At first I didn’t believe it,” says Stefaniuk, describing the first time the LED lit up. “I thought that I hadn’t disconnected the external power source, and that was why the LED was on.
“It was a wonderful day. We invited students, and I invited professors to see, because at first they didn’t believe that it worked either.”
The reason for the excitement? This innocuous, dark lump of concrete could represent…
