Walking Water Rainbow

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Are you looking for a fun, colorful, science experiment for Saint Patrick’s Day or maybe to brighten up your home from the cold weather? Try out this Walking Water Rainbow!

What you need:

  • 5 clear glasses or plastic cups
  • 4 half size paper towels (folded accordion style)
  • 3 different food colorings (we used the primary colors)
  • a spoon for mixing

What you do:

  1. Fill 3 of the 5 glasses with the same amount of water. We filled ours a little over halfway.
  2. Drop 3 drops of one color food coloring into 3 glasses and mix.
  3. Arrange the glasses with no food coloring between the glasses with the food coloring.
  4. Lay the accordion folded paper towels between each glass (as pictured below).
  5. Wait ~24 hours and check on the glasses occasionally to see what is happening!
This is how your set up should look to start the experiment.

What is happening?

The water travels up the paper towel (almost defying gravity) through the process of capillary action. This is the same process that occurs in nature with plants. Plants use capillary action to “suck up” water and nutrients with their roots to the rest of the plant! There are attractive forces between the water and the paper towel.

In addition to capillary action, we see some color mixing! Since we used primary colors (yellow, blue, & red), we were able to observe how yellow and blue create green and red and blue create purple or secondary colors.

If you have white flowers such as Queen Anne’s Lace or white carnations, you could also place them in each of the glasses after the experiment and watch the flowers quite literally soak up the colors into the white petals!

Have you tried this experiment before? What did you think?


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