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.