The Prism on Dr. Nakamura's Desk

In a physics lab at the University of Chicago, Dr. Keiko Nakamura would begin each semester the same way. She held a glass prism up to the window and let a beam of ordinary sunlight pass through it. What appeared to be simple white light fanned out across the far wall in a stunning cascade — red, orange, yellow, green, blue, indigo, violet.…