Review: What is refraction? Refraction occurs when light bends Light bends as it passes from one substance to another Ex. A straw in a glass into water Refraction can be caused by a lens A lens is a transparent object with at least one curved side that causes light to bend More curved sides = more light bends
Lenses Concave and convex lenses form images OPPOSITE to that in concave and convex mirrors Convex lens Thicker in the center than at the edgesex: magnifying glass Concave lens Thicker at the sides that in the center ex: glasses for people that cannot see far objects
Convex lenses Light rays travelling through a convex lens are bent so they meet at a focal point Image formed is similar to that of a concave mirror If the object is 2+ (or more) focal lengths from the lens, the image appears inverted and smaller If the object is closer to the lens than one focal length, the image is upright and larger
Concave lenses Light rays travelling through a concave lens are bent and spread away from each other, do not meet Image formed is similar to thatof a convex mirror Image formed is upright and smaller than the object Ex: eyeglasses if you cannot see far
Which pictures show a concave lens? Convex lens? How do you know?