Try the Radical Rainbow Experiment


  • Sheet of Paper Towel
  • Washable Markers
  • 2 Small Glasses
  • Water
  • Ruler 
  • Scissors


  1. Take a sheet of paper towel and fold it in half the long (hot dog) way.
  2. Measure and cut the paper towel so that it is no longer than 7.5” to ensure that the experiment works correctly.
  3. Hold the paper towel vertically and color one inch tall rectangles starting with red, then orange, yellow, green, blue and purple.  Do the same on the other end of the paper towel so that the ends match (red will connect with red and so forth).  Make sure that the colors are very saturated.
  4. Take your two glasses and fill them about ¾ full of water.
  5. Place the ends of your paper towel into the cups so a small section of the paper towel is in the water, but does not touch the bottom.  If too much paper towel is in the water, the dye may dissolve instead of moving up the paper towel.
  6. Form an arch with the paper towel and then place the other end into the other glass of water. 
  7. In 10-15 minutes you will see the blank paper towel transform into a colorful rainbow!
Activity by Nicole Little, Floating Teacher
Photo Credit & Inspiration: 
Posted in Activities, After School, Art, At Home, STEM, Upham.