1. Refraction (Slowing Down) When a wave passes into a medium that makes it slow down, the wave will bend toward the normal Air Water

2. Refraction (Slowing Down) When a wave passes into a medium that makes it slow down, the wave will bend toward the normal Air Water

3. Refraction (Speeding Up) When a wave passes into a medium that makes it speed up, the wave will away from the normal Air Water

4. Refraction (Speeding Up) When a wave passes into a medium that makes it speed up, the wave will away from the normal Air Water

5. The Law of Refraction An important property of transparent substances is the index of refraction.

6. The Law of Refraction An important property of transparent substances is the index of refraction. Index of Refraction – the ratio of the speed of light in a vacuum to its speed in a given transparent medium

7. The Law of Refraction

8. Practice Light travels through a vacuum at a speed of 3.00 x 10 8 m/s. Determine the speed of light in the following media: water (n = 1.333) v= 2.25 x 10 8 m/s

9. Practice When the ray travels through the two materials, does light begin to move faster or slower? Faster! (bending away)

10. Snell’s Law The index of refraction of a material can be used to figure out how much a ray of light will be refracted as it passes from one medium to another. As you will see as you do more problems, the greater the index of refraction, the more refraction occurs. But what if you are trying to find the angle of refraction?

11. Snell’s Law n i (sinΘ i ) = n r (sinΘ r ) index of refraction of first medium x sine of the angle of incidence = index of refraction of second medium x sine of the angle of refraction

12. Practice Find the angle of refraction for a ray of light that enters a bucket of water from the air at an angle of 25 degrees to the normal Draw a diagram first, then find the angle of refraction n i = 1.00 n r = 1.333 1.00sin(25)=1.33sinx 0.3178 = sin x X = 18.52