The lab uses a computer simulation from PhET, which is found at the following website.

• PhET Bending Light Simulation https://phet.colorado.edu/en/simulations/bending-light

Title: Index of Refraction of Water Objective: You will measure index of refraction of water and other material. Apparatus: Go to https://phet.colorado.edu/sims/html/bending-light/latest/bending-light_en.html Background Theory: Let's suppose that light waves encounter a plane surface of a piece of glass after traveling initially through the air. What will happen to the speed of light? The speed of light in glass or other transparent medium is lower than the speed of light in vacuum. The speed of light in a substance can be described by a quantity called the index of refraction as shown in the following equation. where v: speed of light in a substance, c: speed of light in vacuum(3.0x 10 m/sec), n: index of refraction of a substance. In this lab, you will measure the index of refraction of water. Experimental Method: 1. Place a protractor at the boundary of air and water. 2. Press a red button on the light source and set angle of incidence at10 degrees and measure angle of refraction. Then increase angle of incidence with an increment of 5 degrees up to 60 degrees and measure corresponding angle of refraction. 3 Change material from water to material A and repeat above step2. 4. Calculate the index of refraction of water for each incident angle using Snell's law. Mastersin water = MairsinCair where n for air is 1.000. Record values for nwater in the data table. Find the accepted value of the index of refraction of water from the simulation. Data: Index of refraction for water Index of refraction of material A Trial Oair Owater Sin(Oair) |Sin(Owner) nwater Trial Oair OmmA Sin(Oair) Sin(Omma) nmatA 100 1 10" 2 150 2 150 3 200 3 20" 250 4 250 5 5 30 6 350 6 35" 7 40)0 7 40 450 8 450 509 50" 10 550 10 550 11 60 11 60" 20 Average index of refraction of water: Average index of refraction of matA: % error of the index of refraction of water: Questions: Q1 What is the average index of refraction of water? Q2 What are some sources of error? Q3 What is the speed of light in water