# Refraction

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### Instructions

1. Select Top Material A (a Vacuum) and Bottom Material B (Water), and note the change in the refraction angle and colors
2. Select "incident angle", and either use the bar or type into the box 40 degrees. You may have to click on the picture to have the picture updated
3. According to Snell's Law,

since the index of a vacuum is 1 and the index of water is 1.33, we can see that the refracted angle is about 28.9 degrees, since

now select "refraction angle" and type in 28.9 degrees to see how close the incident angle comes to 40 degrees. Note that the computer needs to convert degrees into radians and is less accurate than your calculator due to the rounding error.

### Challenge Questions

1. Ptolemy of Alexandria (second century CE) has the oldest measuurements of how a beam of light is refracted from air into water. Record the difference between his observations and ths simulation (and your calculator) (Air is Material E)
incidence angle Ptolemy's refraction angle simulation calculation
10 7.75
20 15.5
30 22.5
40 29
50 35
60 40.5
70 45.5
80 50
2. What is the refractive index of K? (Hint:If you choose the Top Material to be a vacuum and the Bottom Material K, you can compute the index by computing the ratio of the sines of the angles!--see number 3 on the instructions above)

3. What is the refractive index of L?

4. Which is a Diamond?

5. What is the difference between the angle of incidence and the angle of refraction if the Material is the same?

6. What material refracts a beam of light from air at an angle of 45 degrees into a 30 degree angle?

7. What angle of incidence causes the most dramatically different angle of refraction?