Olivia received a hand-out sheet which reviewed reflection in a curved mirror, and showed ray diagrams. A short video was used to demonstrate that refraction taking place at the surface of two media was due to changes in speed of the wave. A 90 degree approach of the wave front and an approach at other than 90 deg. was shown and explained in terms of speed changes. We then discussed, using a set of whiteboard optic lenses, the definition of a lens and the two major classifications of lenses, convex and concave and Olivia arrived at a definition of convex lenses based on the thickness between the edges and the optical center of the lens. A demonstration using a beam of light showed that convex lenses are also converging lenses.