If you're seeing this message, it means we're having trouble loading external resources for Khan Academy.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Colored shadows

2 articles
5 videos
Are shadows always black, or can they take on the colors of the rainbow? In this hands-on science snack, which was developed and demonstrated by Exploratorium Senior Scientist Paul Doherty, you’ll have fun with colored lightbulbs, experiment with additive color mixtures, and learn about human color perception. Watch the videos, build your own colored shadows, and see how exciting light and shadow can be.

Build your own colored shadows: Materials & steps

VIDEO 2:13 minutes
Here's everything you'll need to build your own colored shadows. 

What's going on: light travels in straight lines

VIDEO 0:55 minutes
What's the science behind the phenomenon of colored shadows? Light travels in straight lines, but we have three different-colored bulbs spaced several inches apart.

Yellow and cyan challenge

VIDEO 1:06 minutes
Now that we understand how the magenta shadow is produced, what about the other colors we see?

Yellow and cyan solution

VIDEO 1:03 minutes
Each color you see comes from the pencil blocking one of the lights and the other two filling in the shadow.