How Are Rainbows Made?

Red, orange, yellow, green, blue, indigo, violet. What do these colors make up? If you said “rainbow,” you’re exactly right!

It’s always exciting to see a colorful rainbow in the sky after a rainstorm. But have you ever wondered how a rainbow is made?

Rainbows need two important ingredients to appear: water droplets and sunlight. Light from the sun travels to the earth in waves of the colors we see in a rainbow. When the waves of light hit drops of water, a process called refraction (ree-FRAK-shun) occurs. During refraction, the light reflects off the inside of the water and changes direction. Another process called dispersion (dis-PER-shun) also happens, separating the sunlight into all the colors of the rainbow. The different colors of light are reflected off the raindrop toward our eyes, creating a rainbow.

In Genesis 6–9, God sent a worldwide flood as punishment for people’s sins. After the flood, God put a rainbow in the sky as a promise to never again flood the whole earth. The next time you see a rainbow stretching across the sky, remember God’s vow and thank him for being faithful to keep his promises.

“‘I establish my covenant with you, that never again shall all flesh be cut off by the waters of the flood, and never again shall there be a flood to destroy the earth.’ And God said, ‘This is the sign of the covenant that I make between me and you and every living creature that is with you, for all future generations: I have set my bow in the cloud, and it shall be a sign of the covenant between me and the earth.’” Genesis 9:11–13

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Colorful Facts:

• The colors that make up a rainbow always appear in the same order. The order is based on the length of the waves (wavelength) they travel in—red appears at the top of the rainbow because it has the longest wavelength, and violet appears at the bottom because its wavelength is the shortest.
• Did you know? Rainbows can also appear at night! These are called moonbows. Moonbows are rainbows that are reflected by the light of the moon instead of the sun.

Make Your Own Rainbow!

You can make your own rainbow using items you have around your house. Make sure it’s a sunny day!

What you’ll need:

• Small handheld mirror
• Glass of water
• Window

Instructions:

1. Place the glass of water on a table. Put the mirror at an angle inside the glass of water.
2. Turn off the overhead lights.
3. Position the glass so the sunlight through the window shines directly at the mirror. You may have to adjust the mirror.
4. Look for the rainbow reflection on the wall the mirror is facing.