Give physicists a sandbox, and they can build a career in it. Indeed, many physicists see a sandbox as a sort of universe in miniature. Probing the forces in moving sand, called granular flows, has recently revealed new insights into landslides, earthquakes, and the evolution of the cosmos--and is even helping to predict Wall Street's gyrations.
But when Alexander D. Wissner-Gross boned up on sandbox physics in 1998, at the tender age of 16, his imagination took off in the opposite direction. Instead of contemplating giant events, he thought about the world of the unimaginably small--and of the emerging field called nanotechnology. The goal here is to build everything from microchips and drugs to household appliances, molecule by molecule, or even atom by atom. But there's a hurdle nobody has managed to surmount: the lack of processes that can use individual atoms and molecules as building blocks and quickly assemble them into products. Coaxing nanobits to self-assemble chemically is one promising approach. Wissner-Gross thought sand could offer another solution.