February At-Home STEAM Activity: Walking Water

Let’s make a walking water rainbow.  In this fun, hands-on, and colorful science experiment, little scientists will learn about capillary action.

Capillary Action is the ability of a liquid to flow upward in narrow spaces without the assistance of external forces. Capillary action is how water moves up into a plant’s roots and up the stem to the rest of the plant.


  • 6 wide-mouth glasses or jars
  • 6 white paper towels
  • Red, yellow, and blue food coloring.


  1. Fold each paper towel into thirds lengthwise. Paper towels can be cut shorter to fit in glasses. Test your paper towel strip to make sure they properly fit in your glasses. Paper towels should be able to go from the bottom of one glass to the bottom of the next glass.
  2. Place the 6 glasses in a line.
  3. In the first glass, squirt a generous amount of red food coloring.
  4. Squirt the same amount of yellow into the third glass.
  5. Squirt the same amount of blue coloring into the fifth glass.
  6. Pour water into the glasses with color. Fill almost to the top. Leave the other glasses empty. Arrange the glasses into a circle.
  7. Starting with the glass filled with red, place one end of a paper towel into the glass and the other end of the paper towel into the empty glass next to it.
  8. Continue placing paper towels into the glasses until the last paper towel is placed into the glass of red.
  9. Observe the changes that occur due to capillary action, how quickly did your water rainbow walk?