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

Walking Water Rainbow Experiment

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

Instructions:

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!

What is creating the walking water rainbow?

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! We used primary colors (yellow, blue, & red). We observed how yellow and blue create green. Then we also saw that red and blue create purple or secondary colors.

If you have white flowers like Queen Anne’s Lace or white carnations, place them in each glass after the experiment. You can watch the flowers soak up the colors into the white petals!

Have you tried this experiment before? What did you think? Let me know in the comments!

You can check out my other experiments and activities here.

-Kristen