Why Rainbows Happen — Simple Explanation and Easy Home Experiment for a 7-year-old

Kid-friendly explanation of how rainbows form, the order of colors (ROYGBIV), and two safe, step-by-step experiments a 7-year-old can try at home with an adult.

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Rainbows: A Simple Explanation for a 7-year-old

A rainbow is a beautiful band of colors in the sky. It happens when sunlight meets tiny drops of water in the air, like after rain. Sunlight looks white, but it is really made of many colors mixed together. When the light goes into a raindrop, it bends and splits into all those colors, and then bounces back to your eye. That makes the colors show up in a curve in the sky.

What are the colors and their order?

  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Indigo
  • Violet

You can remember the order with ROYGBIV. A fun rhyme is 'Richard Of York Gave Battle In Vain' or just learn ROYGBIV.

Why does each color show up in a different place?

Each color bends by a little different amount when it goes into the raindrop. Red bends the least and violet bends the most. That is why red is the top color of the rainbow and violet is the bottom color.

Try this safe experiment at home (ask an adult to help)

  1. Find a sunny day and get a clear glass or a clear plastic cup and a sheet of white paper.
  2. Fill the glass about three quarters full of water.
  3. Take the glass outside or hold it near a sunny window. Put the white paper on the ground or on a table where the sunlight can hit it.
  4. Hold the glass so the sunlight shines through the water and onto the paper. Move the glass slowly and tilt it until you see a little rainbow appear on the paper.
  5. Look closely and you will see the separated colors. Take turns moving the glass and the paper to get a brighter rainbow.

Other ways to see rainbows: spray water from a garden hose on a sunny day, or use a flashlight and a clear prism or a CD with an adult's help.

Fun facts

  • A rainbow is actually a full circle, but the ground usually blocks the bottom part, so we see an arc.
  • Sometimes you can see two rainbows. The second one is fainter and the colors are reversed.
  • You can never reach the end of a rainbow because it changes with where you stand and the raindrops around you.

Have fun looking for rainbows and trying the experiment. Remember to ask an adult to help when using water, glass, or a hose.

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