Refraction occurs when light waves bend as they are passing from one medium to another. Causes a change in: Causes a change in: – Speed – Wavelength – Direction the frequency of a wave remains constant therefore, consistent w/the wave equation (V = ƒʎ), wavelength must change. light slows down In a vacuum, all EM waves have a speed (c) of 3x10 8 m/s. In other materials, light slows down.

In which way does a light change as it travels from glass into air? a.Frequency increases b.Frequency decreases c.Speed decreases d.Speed increases

index of refraction (n) The index of refraction (n) is a measure of how much light slows down in a material. – The number describes the ratio of the speed of light in a vacuum to the speed of light in the new material slower larger – The slower the wave moves in the material, the larger the “n” value

Crown Glass Crown Glass is n = 1.52, meaning that light travels about 1.5 times slower in crown glass than in vacuum The index of refraction in a vacuum is n = (speed of light at full capacity)

n 2 = 1.5 n 1 = 1.0 A B fast to slow towardsthe normal A light ray traveling from a fast to slow medium ( low “n” value to high “n” value) will bend towards the normal

slowto fast away from the normal A light ray traveling from a slow to fast medium (high “n” value to low “n” value) will bend away from the normal

Arthur Podd's is spearing fish while standing on the shore. The actual location of a fish is shown in the diagram below. Because of the refraction, the observed location is different than its actual location. Indicate on the diagram the approximate location where Arthur observes the fish to be Indicate on the diagram the approximate location where Arthur observes the fish to be Must Arthur aim above or below where the fish appears to be in order to strike the fish??? Must Arthur aim above or below where the fish appears to be in order to strike the fish??? This is not really me; this is my IMAGE!!

Arthur must aim at a position on the water below where the fish appears to be. Since light refracts away from the normal (water to air) as Arthur sights at the fish, the refracted ray when extended backwards passes over the head of where the fish actually is.