Rainbow Walking Water
Ages 5 and up.

It’s already March! As we get ready for a month full of fun Springtime events, we thought we would start with this activity that lets kids make their own rainbow indoors. Using some basic kitchen supplies, kids can learn about capillary action. Capillaries are the tiny tubes in the cellulose within plants that allow plants to collect water, in spite of gravity. Paper towels, made of plants and designed to use capillary action to soak up spills, allow the ink to travel upwards. Try this fun experiment and then head outside to check out the plants that are starting to bloom.



  • 7 small clear plastic cups or glasses
  • 6 paper towels (cut in half)
  • Red, yellow, and blue food coloring
  • Water


  1. Line up the 7 cups in a row and fill every other one, starting with the first one, about 3/4ths of the way full with water.
  2. Add 5 drops of red food coloring to the first and last cup.*
  3. Add 5 drops of yellow food coloring to the third cup.
  4. Add 5 drops of blue food coloring to the fifth cup.
  5. Fold the pieces of paper towel in half hotdog style, and then again hotdog style.
  6. You can cut excess paper towel off as you want there to be just enough to drape the paper towel between two cups with one end at the bottom of either cup.
  7. Take one folded paper towel and put one end into the first cup and the other half in the empty cup next to it. Place another paper towel similarly between the second and third cups. 
  8. Repeat this process and place a paper towel between each cup and the ones next to it.
  9. Watch and wait as the water begins to slowly move up the paper towels and fills the neighboring cups (this will take about 40 minutes for the empty cups to fill).

*Ensure that each cup that starts with water receives about an equal amount of food coloring for best results

More Fun!

Rainbow facts: Learn more about Rainbows here! 

Learn more about Capillary action here!