Simple science activities are our favorite. This experiment is incredibly easy to prepare, and children are always fascinated by the final result. Discover color blending and capillary action with this straightforward walking water experiment!
RELATED: Rainbow Growing Experiment
Children of every age can enjoy trying this science project! They will be astonished to see a rainbow develop through capillary action. This activity is also a helpful way to explain color blending and rainbows.
Materials Required
For this activity, gather the following supplies:
- Paper Towel – 6 folded half sheets
- Food Coloring – we prefer the liquid gel food coloring (only 1 drop is needed), though standard food coloring is suitable as well
- Water
- 7 Small Clear Cups or Glasses
View the Video Guide
How the Science Works
This activity provides an excellent demonstration of color blending and capillary action.
Children can see how secondary colors develop as orange, green, and purple appear in the vacant cups.
Capillary action causes the dye to travel through the paper towel. Water rises through the towel and carries the food-coloring molecules along with it. This is the same process that helps trees draw water from the soil through their roots. Paper towels consist of plant-based fibers known as cellulose.
Walking Rainbow Experiment Directions
1. Begin by pouring water into 4 clear cups.
Add water until each cup is nearly full.
A greater amount of water will help the walking water move more quickly.
2. Put 1 drop of red food coloring into two cups, 1 drop of blue coloring into one cup, and 1 drop of yellow coloring into the final cup.
When using standard food coloring, you might have to use several drops.
With the red and blue coloring, be careful not to make the mixture overly strong.
If the colors are too intense, the resulting purple may appear nearly black after they combine.
3. Arrange the cups in a row, placing a red cup at both ends.
After the colors combine, the rainbow will appear in this sequence.
4. Fold 6 half-sheets of paper towel and cut approximately 1/4 from the ends to keep them from being too long.
5. Put one paper towel into every cup, linking it to the neighboring empty cups.
6. Almost at once, the water and coloring will begin traveling through the paper towel into the empty cups.
Combining blue and red produces purple.
When blue and yellow combine, they create green.
Red mixed with yellow results in orange.
7. Allow 2-3 hours for the empty cups to become filled with the new colors created by mixing the other 2 cups.
Your walking rainbow is now finished! Each rainbow color can be seen in the cups, while the previously empty cups are filled with the secondary colors – orange, green and purple!
Note – to perform the experiment in a circle rather than a straight row and conserve space, simply prepare 1 red cup and arrange the cups in a circle (as shown in the first image).
Children will enjoy observing the water move and watching new colors form during this simple science experiment!
Additional Science Experiments for Kids
Give this enjoyable and simple Grow a Rainbow Experiment a try. All you need are washable markers and a paper towel!
For another enjoyable activity, prepare some oobleck!
Experiment with a rainbow rain cloud in a jar!
