Photo of supplies needed to make a rainbow at home. These include a mirror, a glass of water, a flashlight, a CD, marbles, or a crystal.

Try This: Make a Rainbow

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Can you make a rainbow on the walls of your home?

Can you make a rainbow on the walls of your home?

Using just a flashlight and materials like a CD, a glass with water and a mirror, a crystal, and glass knick-knacks, we made all sorts of rainbows. If you pick the mirror and glass of water method, you’ll need to have a mirror that can fit *inside* the glass of water.

This works best with a flashlight with a very white light (like the one on your phone), in a dark room on a light-colored wall. Shine the light on (or through) the objects and see what you can create!

Okay, now here’s the science

To see a rainbow outside you need two things: sunlight and rain 

The color in the rainbow comes from refraction.

Refraction is the bending and slowing of light when it goes from air into the water of a raindrop.

Sunlight bends when it enters the droplet, bounces around inside and bends again when it exits the drop. Violet light bends and slows more than red light, so the color separates into a rainbow!