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Rainbow Science Activity Inside!

Light is made up of a spectrum of wavelengths, each with a different color. It’s easy and fun to separate them and create a rainbow! These elementary-level science activities are perfect for a sunny day. If the weather’s not cooperating, you can do them inside too, with a flashlight in a dark room.


Here’s what you’ll need: A CD A blank wall or a white surface (I propped open a white binder) A sunny day (or a flashlight) White paper Scissors Tape


  1. Sit or stand facing the sun. Make sure your white surface is facing you.
  2. Holding the CD in front of you, blank (unprinted) side toward the sun, tilt it at an angle that reflects the light onto your white surface.
  3. Tilt the CD at different angles and watch the colors and patterns change.
  4. Back away from your surface, and then get closer again. Notice how the reflection changes.

What’s happening? When the white light hits the CD, it reflects, or bounces back, onto the white surface and the colors in the light are dispersed into the spectrum. Dispersion happens whenever the light changes direction, as it did when it bounced off the CD. When the white light bends, each of the colors in the spectrum bends at a slightly different angle, separating them out for you to see.

Get crafty Now trace your CD a few times onto white paper. Cut out the circles and cut patterns into them, like paper snowflakes. Tape one of the patterned circles onto your CD and repeat the experiment above.

One more thing Refraction is the bending of light. When light passes from one medium to another, it bends because it’s traveling at a different speed. You can run around your yard, for example, at a different speed than you could run around a swimming pool.

It’s easy to show this with just a glass of water and a pencil. Put the pencil in the water. It looks bent, but of course it’s not! Pull it out and then put it back in. As light passes from the air to the water, it bends, traveling to your eye at different speeds and creating the illusion that the pencil is bent or broken!

Did you know? Light travels at 186,000 miles per second. That means the light that you see outside now left the Sun about eight minutes ago!

Now, can your child explain how a rainbow is created in the sky? It’s caused when light from the sun enters water droplets, reflects off their insides, and then each of the colors in the light refracts at a slightly different angle. And that’s the science of rainbows!