This page contains full project details. For the summary, please see the Project Summary.
Science Fair Project Description
Get ready to witness a rainbow magically appear as colored water defies gravity and moves from cup to cup, showcasing the sticky qualities of water - the power of capillary action.
Hypothesis
The hypothesis is that the colored water will travel along the paper towels, reaching the empty cups where color mixing occurs, ultimately resulting in a mesmerizing walking rainbow effect.
Overview
Watch as colors move from cup to cup in a mesmerizing display. By setting up cups filled with primary colored water and connecting them with paper towels, you'll see the fascinating phenomenon of capillary action as the color moves up the paper towel. When two different colored waters reach the empty cup, color mixing occurs, creating a stunning walking rainbow effect. Explore the concepts of capillary action and the color wheel as you unlock the secrets behind this captivating magic science trick.
Fold a paper towel strip so that when it's put in between two cups, each end touches the bottom of each cup. Make 6 of these paper towel strips.
Pour water into the 1st, 3rd, 5th and 7th cup. The 2nd, 4th and 6th cups don’t have any water.
Put a few drops of red food coloring into the 1st cup, a few drops of yellow food coloring into the 3rd cup, a few drops of blue food coloring into the 5th cup and a few drops of red food coloring into the 7th cup. Stir or swivel the cup so that the food coloring is well mixed.
In between each cup, place a paper towel strip so that one end touches the water, and the other end is in the next empty cup. Do this for each set of cups so that there is a paper towel strip between each adjacent cup.
Watch as rainbow colors form in the cups.
Results
The colored water climbs up the paper towels, appearing to defy gravity. When the colored water reaches the empty cup, it mixes with the colored water coming from the other paper towel. The two different colors mix, forming a new color! At the end, a rainbow is formed from the colored water moving to the empty cups and mixing to form new colors.
Conclusion
In this walking water science experiment, water moves up the paper towel and into the empty cup in a process called capillary action. This is the same way water moves up a plant's roots.
When the red, yellow and blue water moves up the paper towel into the empty cups, the colors mixed in there, forming a rainbow!
Let's look at each part of the rainbow walking water experiment to see how this works!
How do the paper towel and water work together?
Capillary action occurs between the paper towel and water due to cohesive and adhesive forces. Cohesive forces tightly hold water molecules together, while strong surface tension enables water to be drawn up the paper towel. In addition, attractive forces between water molecules and the paper towel fibers allow water to move upward.
How do 3 colors of food coloring form a rainbow of 6 colors?
The red, yellow and blue food coloring used in the rainbow paper towel experiment are primary colors. When two different primary colors come together in an empty cup through capillary action of the paper towel, they mix to create secondary colors. On a color wheel, you can observe that red and yellow make orange, yellow and blue make green, and blue and red make purple. Taken together with capillary action, a beautiful display of rainbow colors is created in the walking water science experiment!
Also consider
Try using different temperatures of water to see how it affects the speed of absorption.
Try different kinds of paper towels. Is there a difference if more absorbent paper towels or thinner paper towels are used? Do you think more absorbent paper towels work faster to move the water between cups?
Use different ways to fold the paper towel. Is there a difference in how fast the rainbow is formed if folded paper towel verses rolled paper towel is used in the experiment?
Experiment with uneven amounts of water to observe how it impacts the formation of the rainbow.
Hey there! Here are some awesome videos about this science project that we think you'll really like. They're not only super fun, but they'll also help you learn more about the science behind the project. So sit back, relax, and get ready to have some fun!!
In this demonstration from the Aberdeen Science Centre, glass jars are used in the rainbow walking water experiment, and at the end, all the jars are filled with the colors of the rainbow! The capillary action you see in this rainbow water experiment is also what draws water up through plant roots into the leaves and flowers!
Follow along with these step-by-step instructions for the Rainbow Walking Water science experiment, brought to you by the Miami Children's Museum!
This is a sped up video of the rainbow walking water science experiment from the Science Museum Oklahoma. Notice what happens to the empty glass!
