This quick project was a neat follow up to Travis’s exploration with his Rainbow Optics Crate. And to make it, we even got to upcycle the box from Kiwi Co.!

Cut any extra flaps from the box, including those that fold in to the sides and front. Tape a blank CD to the inside of one short end, flush against the back wall. Make sure your box can close!

Trace around the end of a paper towel tube twice, in overlapping circles, so you have an opening that’s about 1 and 1/2 times as wide as the tube. Insert the tube at an angle, looking towards the CD.

Also cut a slit on the short edge directly opposite the CD, to let in light. Tape up any other edges where light might slip in.

Now take a peak inside! We found this worked best when we shined a flashlight directly into our slit. One person can shine the light while the other person makes sure the tube is aimed properly at the CD; you’ll see the spectrum of the rainbow appear.

You can also try this with other light sources, including sunlight, and see which one works best!