Refraction

• refraction - the change in the direction of light when it passes from one medium to another of different optical density
• optical density - related to the transparency of a material to light
• the higher the optical density of a material, the slower light travels through it
• higher index of refraction = higher optical density
• denser medium - less dense medium = move away from normal
• less dense - more denser = move toward normal
• convex lens - thicker at the middle than the edge
• concave lens - thicker in the edges than the middle
• convex lenses are CONVERGING lenses
• concave lenses are DIVERGING lenses