Blink and you might miss it, but if you keep your eye on the monitors in professor Sebastian Will's lab, you'll catch a series of single-second flashes that light up the screen. Each flash is an atom of strontium, a naturally occurring alkaline-earth metal, being briefly captured and held in place by "tweezers" made of laser light. "We can see single atoms," says graduate student Aaron Holman. "Seeing those never gets old."