Purpose
Observe and analyze the properties of polarized light.
Concept
If you wear polarized sunglasses, and look at the reflection of sunlight off of water, the glare from the reflected light will almost disappear. Since light is a transverse wave it can be vibrating vertically, horizontally or any angle in between.
The transverse waves in sunlight are oriented randomly. When sunlight reflects off of certain surfaces, the light oriented in one direction is not reflected as well as light reflected 90 degrees from that angle. This makes it partially polarized.
Polarized filters are designed to let polarized light pass through at one angle, but block light from passing through 90 degrees from that angle.
Procedure
1. Hold one polarizing filter between the laptop display and your eyes. Slowly rotate the filter one revolution. Observe and record the intensity of the display at different angles.
2. Hold one polarizing filter between the lamp and your eyes. Slowly rotate the filter one revolution. Observe and record the intensity of the lamp at different angles.
3. Repeat step 2 with a second filter between the lamp and your eyes. Observe and record the intensity of the lamp at different angles.
4. Carefully shine the laser through a polarizing filter so that the beam of light strikes the page in a notebook. Observe and record the intensity of the reflected laser light at different angles.
5. Repeat step 4 with a second filter between the laser and the notebook. Observe and record the intensity of the reflected laser light at different angles.
Analysis
1. Is the light from a laptop display polarized? Explain.
2. Is the light from a lamp polarized? Explain.
3. Is the light from a laser polarized? Explain
4. Describe an experiment that you could do to test whether sun light, reflected off of a window, is polarized.
