Lesson: Convex Lenses Physics • 9th Grade

Students will be able to

• qualitatively describe convexity of a lens (thick in the middle and thin 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 convex lens at different distances perpendicular to the optical axis of the lens,
• explain that the change in the light ray travel direction is due to refraction and so depends on the material that the lens is made of,
• demonstrate that parallel rays entering a convex lens converge at a focus point that is on the side of the lens that the rays exit from,
• recall that the distance between the center of the lens and the point that parallel incident rays converge at is called the focal length,
• recall that the power of a lens is the reciprocal of its focal length.