The point where light rays converge after passing through a lens is called the focal point. The distance from the lens to focal point is called the focal length. Concave lenses are thicker on the edges than in the middle. They cave in toward the center. Things look smaller through a concave lens.
Concave lenses make light rays bend outward or diverge.
A concave lens will spread a beam of light on a surface. In this activity students will explore and discover the properties of the two basic types of lenses. Students can work individually, in pairs, or in small groups. This can be an activity guided by the teacher or students can work independently using the Student Page as a guide. After distributing the materials, allow students ample time to explore the materials freely.