Spectroscope

Study the science behind rainbows with a do-it-yourself spectroscope! You can see all the colors that make up white light from the sun, and the unique color patterns in light from light bulbs and other sources.

  1. Ages: 5 - 16

  2. <30 minutes

  3. A little messy

Step-by-step tutorial

  • Step 1

    Gather your materials!

    Photo reference of how to complete step 1

  • Step 2

    Tape your CD or DVD to the inside of the box so the shiny side is visible. You'll want the disk to be flat against one wall and close to a corner.

    Photo reference of how to complete step 2

  • Step 3

    Close your box and make sure nothing is covering the part of the disk closest to the corner of the box (circled in the photo). We had to trim off an edge of our box.

    Photo reference of how to complete step 3

  • Step 4

    Close the box and use the tube to trace a circle on the long side of the box adjacent to the one the disk is on (about 1/4 of the way along the side). Trace another circle about half a tube-width toward the middle of the side. This will become a slot for the viewing tube.

    Photo reference of how to complete step 4

  • Step 5

    Cut out the oval shape defined by the two circles. You should be able to slide the tube into the hole and aim it toward the CD/DVD.

    Photo reference of how to complete step 5

  • Step 6

    Cut a slot into the wall of the box opposite from the CD/DVD. The slot should be lined up with the part of the CD/DVD that's close to the corner of the box.

    Photo reference of how to complete step 6

  • Step 7

    Close up the box and cover any other holes or slots with tape. Check through the tube to see if there are any light leaks.

    Photo reference of how to complete step 7

  • Step 8

    Aim the box so the slit faces a light source and look through the tube. (NOTE: Never look directly at the sun, even when using your spectroscope!) You should see a rainbow stripe with bright bands. You may need to adjust the size of the slit, the placement of the CD/DVD, or the angle of the tube to get the best rainbow result.

    Photo reference of how to complete step 8

  • Learn moreMagnifying graphic

    What's happening?

    What you're seeing is called an emission spectrum. The CD/DVD is diffracting light, just like a prism (or water droplets in the sky during a rainbow). This splits up the light into its different colors. Sunlight contains a complete band of colors, but you may find that other light sources contain only a few distinct colors that add up to look white! 

    Try looking at lots of different light sources. What kinds of emission spectra can you find?

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