examples of lenses which lead to the definition of lenses. Examples which demonstrate the 2 main types of lenses, convex and concave. Using the lens kit and lasers, showing how a convex lens is actually 2 prisms placed base to base, while a concave lens behaves like 2 prisms placed apex to apex. Tracing incident rays through a convex lens demonstrates that they all refract to a point, making a convex lens a converging lens. The same is done for a concave lens, demonstrating the dispersing or spreading of the refracted rays, making a concave lens a divergent lens.