Feature

Optics for the Fish, Part II

R. John Koshel

Last month I introduced a series of experiments that use water-filled fishtanks to show refraction, reflection, and scattering. This month, I discuss some water-based optical systems that can be demonstrated using your fishtank. The first, "the luminous fountain," is an optical fiber made out of water; the second is an optical communication system that I call an "optical water-guide." The same equipment and supplies described last month are used for the first experiment; for the second, you'll need to procure a modulatable laser, a photodetector, and an audio amplifier with a speaker.