We’ve all seen the message, shown above, written on the side-view mirror of cars: “Objects in mirror are closer than they appear.” Side-view mirrors are convex mirrors, which makes objects appear smaller, or farther away, then they actually are. Some mirrors, such as those in your bathroom, display accurately sized images, while others create images that are larger or smaller than reality. Lenses can be used to magnify or reduce images as well. This chapter will introduce you to convex and concave mirrors, lenses, and the properties of each.
As light rays reflect off of mirrors and pass through lenses, they create images of the object emitting or reflecting the light. In plane mirrors, the images are reversed left to right, though they remain upright. In curved mirrors and lenses, the interactions between objects and their images are more complex. Convex and concave mirrors and lenses can cause images to be diminished or enlarged, upright or inverted, and real or virtual.