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Cool Rainbow Color Experiment

Kids are fascinated by rainbows.

A rainbow is the result of light reflection, refraction and dispersion through water droplets in the air.

A spectrum of rainbow color can usually be seen after rainfall when the air is full of moisture.

Among the spectrum of colors, red, blue and yellow are primary colors.

They can be combined to create the full spectrum including secondary and tertiary colors.

Here is a cool rainbow color experiment perfect for little kids.

Walking water illustration. glasses with blue, red and yellow water are connected using wet paper towels. color walks from one glass to the next, creating rainbow color science experiment.
color rainbow experiment

Cool Rainbow Color Experiment

Prep Time: 30 minutes
Active Time: 2 hours
Total Time: 2 hours 30 minutes

Color can walk! See how color can walk from one glass to another.


  • 3 glasses of water
  • food color in red, blue and yellow
  • paper towel


  • Adult supervision


  1. Put each food color into a glass of water.
  2. Arrange the glasses into a triangle.
  3. Cut paper towel into stripes.
  4. Put the ends of the paper towel stripes into a pair of glasses. There are three pairs: red-blue, blue-yellow, yellow-red.
  5. Wait for the colored water to move upwards along the towel and mix together in the middle.
  6. After about two hours, you should see a ring of rainbow colors: red, purple, blue, green, yellow, orange.

Did you try this project?

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There are two properties at play. Capillary action draws water up the paper towel. Combining primary colors create a spectrum of rainbow colors. Try it! And don’t forget to check out these amazing water properties science experiments.

color wheel diagram
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