Book 7, Question 107
Why Can You Sometimes See a Double Rainbow?
You sometimes see a double rainbow because light can bounce twice inside raindrops. The second bounce makes a fainter bow outside the main one, and its colors are reversed. A bonus bow means an extra bounce!
More fun facts
- The light for the second rainbow leaves the raindrops at about 50 degrees, instead of 42 degrees for the main rainbow.
- That's why the second rainbow always appears above the main one.
- In the second rainbow, red is on the bottom and violet is on top.
- The darker strip of sky between the two rainbows is called Alexander's dark band.
- The dark band is darker because raindrops there don't send sunlight toward your eyes.
Questions kids ask
Why are the colors upside down in a double rainbow?
The light bounces twice inside the raindrops, which flips the order of the colors.
What is Alexander's dark band?
The darker strip of sky between the two rainbows of a double rainbow.