PHY101 Lab 12
Date: July 23rd, 2012
Objective:
The purpose of this laboratory activity is to develop a set of experimental procedures that answer questions regarding Snell's Law and the index of refraction. Ultimately, the experimental procedures you develop will allow the index of refraction to be found for water and cooking oil.
1. Explain how to experimentally determine the index of refraction of two substances. 2. Develop a set of experimental procedures to find the index of refraction for water and cooking oil. 3. Calculate the index of refraction using Snell's Law. 4. Explain critical angle and total internal reflection.
Materials
Materials from Lab Kit:
Laser pointer
Refraction cell
Ruler
Materials student supply:
Cooking oil
Water
Paper
Pencil
Procedures
Water 1. Fill the hemi-cylindrical refraction cell with water. 2. Draw a line on paper that is vertical to the flat façade of the refraction cell. Place the piece of paper under the refraction cell. 3. Open the laser pointer, and bend the direction of light slowly to make sure that the light ray enters the water, and make sure the ray enters at the intersection point of the vertical line you draw and the cell flat façade. 4. Once the ray goes through and refracts in the water and comes out to air from the curving side of the cell, record the point the ray comes out by drawing a dot on the paper using the pencil. 5. Record the line that the light goes from air to water, and connect the dot with the intersection point of the vertical line and flat cell side. 6. Measure the angle Θ1andφ1.
Oil
1. Clean the cell, and refill the hemi-cylindrical refraction cell with oil. 2. Draw a line on another piece of paper that is vertical to the flat façade of the refraction cell. Place the piece of paper under the refraction cell. 3. Open the laser pointer, and bend the direction of light slowly to