A few months ago we tried out the very popular Walking Water Science Experiment using two glasses. It was a fun and super quick experiment that we all enjoyed. So when I found another variation of the experiment I knew we had to try it.
This time, we used three glasses, and we got to observe the water walking AND changing color. We used blue and yellow food coloring, but you could use other combinations as well (i.e. Red & Yellow, Blue & Red, etc). Enjoy!
Color Changing Walking Water Science Experiment Video
- 3 Glasses of Equal Height
- Paper Towels
- Food Coloring (Blue & Yellow)
Step 1 – Prepare two strips of paper towel between 1 and 2 inches wide.
Tip: I used one section of paper towel and folded it in half and then in half again until it was the correct width.
Step 2 – Once you have your two paper towel strips ready, set them aside.
Step 3 – Next, Position your three empty glasses about 2-3 inches apart.
Step 4 – Pour water into the two outside glasses until they are halfway full. Leave the middle glass empty.
Step 5 – Add a few drops of food coloring into the water. Stir the food coloring until the water is all one color.
Helpful Tip: Use blue food coloring in one glass and yellow in the other.
Step 6 – Take one of the strips of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the blue water. Then place the other end into the glass that is empty.
Step 7 – Take the other strip of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the yellow water. Then place the other end into the glass that is empty.
Step 8 – Observe the experiment right away. Do you notice that the water is “walking” up the paper towel? Now, leave the glasses alone and come back to check on them in an hour or two.
Step 9 – Return to the glasses and observe what has happened.
Tip: The longer you wait to check on the glasses, the more water will have moved to the middle glass. The water will stop moving over when all of the cups are filled with the same amount of water.
How Does the Experiment Work?
Why Does the Water Move Between Glasses?
The water appears to defy gravity, but it in reality it moves because of a process called capillary action. The adhesive forces between the water and the paper towel are stronger than the cohesive forces inside the water. As a result, the water travels up and across the paper towel out of one glass and into another.4
Why Does the Water Change Color?
When you mix two primary colors together they make a new secondary color. Because we choose blue & yellow (two primary colors) for our experiment, when the colored water mixed together in the middle glass it turned into green (the secondary color made by mixing blue & yellow together).
You can also try the experiment with the following colors:
Red + Yellow = Orange
Red + Blue = Purple
I hope you enjoyed the experiment. Here’s some printable instructions