STEAM: Walking Rainbow Water

Rainbows are an amazing part of nature and could not happen without water and sunlight. However, did you know you can create a walking rainbow right in your kitchen? Here is how you can create your own water-based rainbow. 


  • Six clear plastic cups or glasses
  • Red, blue and yellow food coloring
  • Three sheets of paper towel
  • Scissors
  • One sheet of white paper


1. Fill three of the cups ½ to ¾ full of water.

2. Add red food coloring to one cup of water, blue to a second cup and yellow to the third cup of water. Arrange the cups into a circle on the white sheet of paper in this order—red, empty, yellow, empty, blue, empty.

3. Lay out a sheet of paper towel and fold it in half lengthwise.


4. Fold the paper towel in half lengthwise one more time.

5. Cut the paper towel in half.

6. Place one end of the paper towel into the colored water and one end into the empty cup—creating a bridge between the two cups. Do this for all the colors.

7. Watch as the color slowly moves up the paper towel and drips into the empty cup. The colors will start to mix after about 10 minutes time.

Things to Think About

Does one color seem to absorb faster than the others? Does the brand of paper towel make a difference in how the color and water are absorbed? How does the amount of water in the cup, or the amount of color added, affect how the colors mix in the empty cups? Could this work with more cups? What about fewer cups?