Supplies:

• 6 small clear cups
• Paper towel 
• Food coloring (red, blue, yellow)
• Water

Steps

1. Fill 3 of the cups ¾ full with water.
2. Add a 5 drops of food coloring to only the 3 cups that have water (5 drops of red in the first cup, 5 of blue in the second cup, and 5 of yellow in the third cup)
3. Place all 6 cups in a circle alternating cups that are empty and water with food coloring (empty, full, empty, full, empty, full).
4. Take 6 paper towels and fold them in half the long way then fold them in half again.
5. Place the cups close together in a line, then dip one end of the paper towel into an empty cup and the other end into the cup with food coloring. Continue until all 6 cups have two ends of  paper towels in them.

Now watch the color process. As the paper towels absorb the colors, you can see the color travel up one side of the paper towels and down the other side into the next cup. After a while the cups that were empty will now fill with colored water.

If you leave the paper towels overnight you will find in the morning that all the cups are filled with colored water. The primary colors mix to create secondary colors and you can see where the colors traveled.

Activity by Cheryl Moy, Bates Site
Inspiration & Photo Credit: www.sciencebuddies.org