spectrometer2Spectrometers are used in chemistry and astronomy to measure light. In astronomy, we can find out about distant stars without ever traveling to them, because we can split the incoming light from the stars into their colors (or energies) and “read” what they are made up of (what gases they are burning) and thus determine their what they are made of. In this experiment, you’ll make a simple cardboard spectrometer that will be able to detect all kinds of interesting things!


SPECIAL NOTE: This instrument is NOT for looking at the sun. Do NOT look directly at the sun. But you can point the tube at a sheet of paper that has the sun’s reflected light on it.


Usually you need a specialized piece of material called a diffraction grating to make this instrument work, but instead of buying a fancy one, why not use one from around your house?  Diffraction gratings are found in insect (including butterfly) wings, bird feathers, and plant leaves.  While I don’t recommend using living things for this experiment, I do suggest using an old CD.


CDs are like a mirror with circular tracks that are very close together. The light is spread into a spectrum when it hits the tracks, and each color bends a little more than the last. To see the rainbow spectrum, you’ve got to adjust the CD and the position of your eye so the angles line up correctly (actually, the angles are perpendicular).


You’re looking for a spectrum (the rainbow image at left) – this is what you’ll see right on the CD itself. Depending on what you look at (neon signs, chandeliers, incandescent bulbs, fluorescent bulbs, Christmas lights…), you’ll see different colors of the rainbow. For more about how diffraction gratings work, click here.


Materials:


  • old CD
  • razor
  • index card
  • cardboard tube
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Comments

5 Responses to “Spectrometer”

  1. christina_andrist says:

    where is the data table?

  2. stephenrknutson says:

    Our kids love this exprement. We tried it with many light sources, including our WeDo 2.0 robot light. Made the robot loop through multiple colors, some of which devided into 2-3 colors. Fun!

  3. 500 or 1,000 lines is fine. If you want, you can get both to compare them with your calibrated spectrometer!

  4. dustin_wyatt says:

    For the worksheet for the advanced spectrometer it says to get a diffraction grating…I have the option of 13,500 lines, 500 lines, or 1000 lines. Which one of those should we get or should we look for something else?

  5. Nohemi Pitts says:

    WOW Aurora! I tried this experiment. It’s very money efficient, and easy as blinking your eyes. To be honest, I really like all of your experiments. One question, Aurora. HOW IN THE WORLD DO YOU LEARN ALL OF THIS!! It’s awesome…