Click GO. It should look something like the image to the right. Using the laser and a protractor, create four unique beams of light (you should NOT have the exact same set of numbers as any other student) one at a time as shown in the Top Substance Bottom Substance figure to the right. vacuum air water oil vacuum air water oil Part 1: Read the protractor to record the incident angle (from the incident ray to the normal line, the dashed perpendicular line from the surface. Then, measure the refracted angle (from the refracted ray to the normal line). Record all data in the table below. The degree sign is provided. Incident Angle (01) Refracted Angle (02) 1. Is the refracted angle larger or smaller than the incident angle? 2. In this experiment the light goes from a lower index of refraction (air) into a higher index of refraction (water). Is the light ray slowing down or speeding up [Hint: think about density]? 3. Based on your data, did the refracted ray bend toward or away from the normal line when it changed speed. Write this down as a rule, "As light the ray bends the normal" Part 2: Set the laser to an angle between 40-70 incident angle and keep it there for each trial (record in table). Use each of the four substances in the table below to see how changing the bottom substance (index of refraction) affects how much the light reflects and refracts. Bottom Substance Incident Angle (0;) Refracted Angle (OR) Water (n=1.33) Oil (n=1.47) (same as above) Diamond (n=2.42) (same as above) Unknown #1 (same as above) Unknown #2 (same as above) As the index of refraction of the bottom substance increases, what happens to the angle of refraction? Is this closer to or further from the normal? 5. Based on your answer to #3, can you figure out which material light is traveling the slowest through? Snell's Law determines the refraction of light, which is how much light bends as it moves from one medium to the next. The equation for Snell's Law is n, sin(0,) = nR sin(OR) Using Snell's Law, a calculator (make sure you are in degree mode), and the numbers in the data table above, you will determine the unknown index of refraction of an unknown bottom substance. For simpler calculations, use n = 1 for air, which simplifies the equation to this: sin(0,) np sin(0) 6. What is the index of refraction for each Unknown? Show your work below.... Unknown #1 n= Unknown #2 n= Summary Questions (Circle the correct choices) 1. The angle of incidence is (greater than / less than / equal to) the angle of refraction. 2. When the light went from the air into water, it went from (low / high) to (low / high) index of refraction. 3. When the light went from the air into water, it bent (closer to / further away from) the normal line. 4. The speed of light in the unknown materials was (greater than / less than / equal to) the speed of light in vacuum (max). 5. Light travels slower in a medium with a (lower / higher) value of n. 6. Light travels slower in a medium that is (more / less) dense. This is (the same as / opposite of) mechanical waves such as sound