Lesson: Concave Lenses Physics

Students will be able to

• qualitatively describe concavity of a lens (thin in the middle and thick at the edges and has a smooth curvature),
• identify the changes in the direction of travel of light rays as they enter and as they exit a concave lens at different distances perpendicular to the optical axis of the lens,
• explain that the change in the direction of travel of a light ray is due to refraction and so depends on the material that the lens is made of,
• demonstrate that parallel rays entering a concave lens can have their paths traced backward to converge at a point that is on the side of the lens that the rays enter from,
• recall that the distance between the center of the lens and the point that parallel incident rays appear to diverge from is called the focal length,
• recall that the power of a lens is the reciprocal of its focal length.