3 Polarizer Experiment

Shine a light through polarized sunglasses and the brightness decreases. If you hold two pairs of sunglasses one way, the light then is completely blocked! Not only that, but when you insert a third pair in between the two allows light to pass through again! Spooky!


  • Three pairs of polarized sunglasses (or three lenses from two old pairs)
  • Sunny window
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5 Responses to “3 Polarizer Experiment”
  1. Aurora says:

    You need to be logged in first.

  2. Olivia Vail says:

    how do you watch the experiment videos?

  3. Rebekah Small says:

    Great, got it now, thank you very much.

  4. Aurora says:

    Did you watch the video the entire way through? It’s because the amount of light that gets blocked depends on the angle between two polarizers. When you only have two, then it’s a 90 degree angle, which wipes out all components of light (vertical and horizontal). If there’s a third at a 45 degree angle inserted, then the light goes from one polarizer to the second, but there’s only a 45 degree angle difference, which means it does NOT wipe out all the light, but still allows some to pass through. Then it does it again by going through the second and third polarizers, since those are again only 45 degrees, not 90, from each other. You must look at the angle one polarizer is to the next one in order to figure out how much light is allowed to pass through, not the initial and final polarizer angles.

  5. Rebekah Small says:

    Help, we still don’t understand why when two polarisers are at 90 degrees to each other a third one in the middle at 45 degrees let light through. the two block out just about all the light but the middle one at 45 degrees changes the light let through the 1st one so it go through at a different direction???

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