Reflection and Refraction Differences and Diagrams Reflection Recall

Reflection and Refraction Differences and Diagrams

Reflection ¢ Recall that reflection is the bouncing of light off of a surface. ¢ Reflection can happen on a variety of surfaces, but the law of reflection still holds true.

Law of Reflection Review Angle of Incidence = Angle of Reflection

Reflection Diagram—Flat Mirror

Refraction is different… ¢ Refraction is the bending of light as it passes through from one material to another. ¢ This affects the speed of the light (very slightly) and distorts the image that you may see.

Refraction makes objects look distorted

Refraction….

Refraction Diagrams

Drawing the refracted ray ¢ The ray will either bend: Towards the normal OR l Away from the normal l ¢ This depends on the index of refraction. l This a value associated with the density of a material. It is represented with an “n. ”

Index of Refraction ¢ The index of refraction is higher for objects that are more dense. ¢ Vacuum is ideal…so its index is 1. 0000. ¢ Water n = 1. 33 ¢ Diamond n =2. 42

Low/High and Fast/Slow ¢ Low n = fast speed of light ¢ High n = slow speed of light

Towards or Away? ¢ When light goes from a low density material (such as air) to a material that is higher density (water) the refracted ray bends toward the normal. ¢ Low to high = bend is toward the normal. ¢ It will have a steeper angle toward the normal as the index of refraction (n) is greater.

Low “n” to High “n”

The opposite happens when… ¢ The light travels from a high “n” material to a material with a lower “n. ¢ High to low = bend is away from the normal. ¢ Example: from water to air

High “n” to low “n”

Summary ¢ When light travels from l Low to high = bend is toward the normal l High to low = bend is away from the normal