Diego and Robin start the day on a ship off the California coast, observing the individual patterns of a lighthouse's beam. They find out how lenses concentrate the rays of light emanating from a lighthouse or a buoy. Robin illustrates the convex lens at the Exploratorium. Also at the Exploratorium, Miguel bounces light with a curved mirror. He goes to the University of Arizona to see the grinding of a glass lens for the telescope at nearby Kitt Peak.MUSIC VIDEO: Light energy from the sun.