Pour each liquid into a dish. Place the dish so that the midpoint of the flat side of the dish is on the center of the protractor. Position the laser on the edge of the protractor and point it at the center of the flat side of the dish. Take the following data for 3 angles of incidence of the laser with the dish. I have included some suggested angles. Liquid Angle of Incidence Angle of Refraction Refractive Index Average Index 20 40 60 12 26 32 Liquid Angle of Incidence Angle of Refraction Refractive Index Average Index 20 40 60 Liquid 20 40 60 13 250 23 31 Angle of Incidence Angle of Refraction Refractive Index Average Index 15 31 42 Calculate the index of refraction for each trial and calculate the average index for each liquid. Calculate the refractive index for the mystery liquid and use this data to identify it. Show your data and calculations below. How could you use refractive index as a measure of the purity of water? Why could it reasonable to assume that the refractive index of air is about 1? (note that refractive index is calculated using)