Physics of Media Arts: Conceptual Physics for Students of the Media Arts

Introduction.

Equipment List.

• A polarizing filters
• Cell phones and other electronic devices with screens
• Light bulbs or other light sources
• Pairs of sunglasses
• A car

Procedure.

1. For each cell phone that you have (there should be at least two), record the manufacturer and model. Then place the polarizing filter on top of the screen. Rotate the filter and see whether the image fades in and out. If so, the device is making linearly polarized light. If you have access to a TV (or multiple TVs), try doing this as well.
2. Identify at least there different light sources (light bulbs). Determine the type of bulb that it is (incandescent, LED, fluorescent, halogen). Then hold the filter between your eyes and the bulb and rotate the filter to see whether that light is polarized. Record your results.
3. Go outside during the daytime and note the time of day. Determine which directions are the compass directions (north, south, east, and west) and the mixed directions (northeast, northwest, southeast, southwest). For each of those eight directions, you will be looking in two locations. The first is near the horizon and the second is at about a 45 degree angle in the sky, leading to a total of 16 locations in the sky. If one of these is towards the sun, do NOT look directly at the sun, but look at a spot in the sky where the sun isn’t. For each location, identify whether there are clouds, and look at it through the filter and rotate it. Describe how the image changes, if at all.
4. Get into a car and position it so that you can see the reflection of the dashboard on the windshield. (In other words, so that you can see the glare of the dashboard.) Hold the polarizing filter between you and the windshield and rotate it. How significantly does the view change?
5. For each pair of sunglasses that you have (there should be at least one), test whether it is polarized using the following method. Hold the sunglasses in one hand and the filter in the other. Hold the sunglasses at arm length and the filter between your eyes and the sunglasses. Rotate the filter and watch the lenses of the sunglasses. If the lenses go dark at certain angles, then the sunglasses are polarized.

Discussion.

1. Sometimes, polarizing filters are used on cameras to take pictures outside, especially under bright sunlight. Describe how the filter affected how the colors look at different locations in the sky and use your observations to explain why someone might want to use a polarizing filter in this case.
2. It is strongly recommended that you use polarized sunglasses when driving in sunny locations. While there is a price difference, you can find polarized lenses fairly cheaply at stores like Walgreen’s and CVS (though you will want to double check to ensure that they really are polarized because not all of them are). Based on your observations from the glare of the dashboard, do you personally think it’s worth getting polarized sunglasses?
3. Do some research on why LCD screens are polarized. Provide a brief summary of what you learned.

Conclusion.

Lab Write-Up Guidance.

• Title and Header.
  What is the title of the lab and who was in the lab group?
• Introduction.
  In your own words, what was the purpose of the lab activity?
• Procedure.
  Describe what you did.
• Results and Data.
  Present your data. Make sure it’s labeled.
• Discussion.
  Answer the discussion questions. Be sure that you state the original question and organize your calculations in a way that is easy to follow.
• Conclusion.
  Write a couple paragraphs about the lab.