Refraction, Diffraction, and Polarization

When light travels through different mediums, light will change speed depending on the density of the medium.

This analogy can be useful:

The observer sees the fish above where it actually is because the light reflected off the fish is refracted when it moves from the water to the air to the observer's eyes.

Here’s a clear explanation of how rainbows are formed with refraction:


Diffraction occurs when light bends around barriers or through openings.

This is what you saw in class and why:

The diffraction grating has tiny scratches in that the light bends around. Different wavelengths will bend at different angles which separates the white light.



Light waves are transverse waves that when they are unpolarized, the waves move up and down in many different directions.  Polarizing filters have small slits that allow only the light waves that are oriented in the right direction to pass through.

This is a cool demonstration with polarizing filters and clear tape.  Light travels through the tape at different speeds (caused by refraction) and then travels through the filter which polarizes the light.

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8 Responses to Refraction, Diffraction, and Polarization

  1. Ade says:

    hey tif
    i am confused about drawing the rays &
    refraction, diffraction. please help!

    • tifftai says:

      Hi Ade,
      I will have to show you tomorrow at school because you missed the class where we measured angles. Come see me at snack or lunch and we can go over it. You’ll also need to copy the notes that you missed.

  2. Elon says:

    Can I please have an extension on the science fair experiment plan, I dont think i will finish it tonight. I have had a lot of other Homework.
    thanks tiff.

  3. Elon says:

    when is the quiz again
    thanks tiff

  4. Gabriel says:

    So I want to use your diffraction grating pic for my light book. Can i make a bibliography of the photo off of your blog. EG date published would be the date you posted the pic

  5. Roman says:

    The pictures with the fence are false.
    The slits doesn’t let the light though,
    it are the dark lines which short-circuit the electric field of light.
    When the slits are vertical, horizontally polarized light passes the filter.

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