The speed of light is constant in a vacuum—but what about in the everyday world? This collection of 23 computer-animated video shorts examines the behavior of light as it passes through physical substances. Outlining Ptolemy’s Law of Refraction and the concept of angle of incidence, the program examines light’s motion through air, water, glass, and other media. Snell’s Law, highlighting the importance of a refractive index, is explored, along with displacement, deviation, dispersion, and the role of refraction in fiber optics. Lens types including bi-convex, convex meniscus, plano-convex, and concave models are studied, in addition to telescopes, magnifying glasses, and the human eye. (70 minutes)