We love rainbow science, and this STEAM / STEM light activity using a blank CD and paper is a really fun one! Not only will kids create rainbow reflections with the CD, but they’ll use paper to alter the patterns of the light.
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In the past we’ve used an old or blank CD and flashlight to create rainbow reflections. (We’ve also made all kinds of rainbows with prisms and a homemade spectroscope!) This time we’re again using a CD to create rainbows, but this time adding cut up paper designs (basically paper snowflakes) to the CD to alter the light patterns. (This post contains affiliate links.)
Rainbow Science: Creating Light Patterns with a CD
Materials for Rainbow Science CD Activity
Directions for Rainbow Science CD Activity
1. Find an area of your house or outdoors to do the activity. You’ll want to be able to access sunlight with your CD and have an area in the shade to reflect the rainbows. (If you don’t have a blank wall, you can use a piece of white poster board.)
2. Use the shiny side of the CD to reflect the sunlight onto your poster board or blank wall and notice the rainbow. What does it look like? Notice the shape and colors. What happens when you change the angle of the CD?
3. Now the super fun part! Trace your CD a few times onto paper so you have circles the exact size of your CD and cut them out.
4. Cut out various snowflake shapes using the paper circles. (You can see our tutorial on how to make paper snowflakes here.)
5. Tape one of your paper snowflakes over the shiny side of the CD and reflect the sunlight onto your poster board or wall. How do the patterns of light look different than before?
6. Try out your other paper designs.
What’s Going On?
A CD is a mirrored surface with spiral tracks or pits. These tracks are evenly spaced and diffract the sunlight (separating the colors). Because the CD’s surface is mirrored, the light is reflected to your eye.
The paper is blocking some light rays from the CD, but letting others through creating all kinds of patterns and designs!
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