Crawling Colors! A FUN Science Experiment in Color Mixing

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Have you ever noticed how water seems to move through narrow spaces, like when you spill something on a paper towel and the liquid spreads out? That’s capillary action in action! It’s a pretty cool scientific concept, and one that’s easy to explore with this crawling colors science experiment!

Ready to grab your printable now? Click here for the Crawling Colors Science Experiment Packet.

In this experiment, we’re going to use food dye, water, and paper towels to observe how capillary action moves liquids from one cup to another. This is a great experiment for kids to learn about science in a hands-on way.

Walking Water Science Experiment for Kids

Plus, understanding how liquids move through narrow spaces is an important concept that can be applied to all sorts of things, from how plants absorb water to how ink moves through a pen. So let’s roll up our sleeves, grab some materials, and get ready to learn about capillary action!

Yield: 1 Science Experiment

Crawling Colors Science Experiment

Crawling Colors Science Experiment
Active Time 45 minutes
Total Time 45 minutes
Difficulty Easy


  • Primary Color Food Dye (Red, Yellow, Blue) or Washable Watercolors
  • Paper Towels
  • Water


  • 5 Small Clear Containers
  • 5 Large Clear Containers
  • Timer


  1. Set up two sets of five cups in a line - one line for large cups and one line for small cups.
  2. For each glass use one sheet of paper towel folded into thirds. Test the paper towels to make sure that the paper towel can go all the way to the bottom of your cups    without sticking too far out. The further the paper towel sticks upwards, the  longer this experiment will take. After testing the towel length, set the paper towels aside.
  3. In the first, third, and fifth cup on each set add in food dye. Red for the first cup, yellow for the third cup, and blue for the fifth cup. Use a liberal amount of food dye.
  4. Fill the cups with food dye 3/4ths full with water. Leave the other two cups empty.
  5. Add the paper towels by placing one end into the cup with water and the other end into an empty cup. Follow the  pattern of ROYGBIV.
  6. Set the timer.
  7. Watch the capillary action take place!


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The Science Behind the Crawling Colors

Have you ever noticed how water seems to spread out on a paper towel? That’s because of something called capillary action. Capillary action is when a liquid can move through really small spaces, like the fibers in a paper towel, without needing any extra help. The liquid sticks to the material (adhesive forces) and also sticks to itself (cohesive forces), which creates a sort of chain reaction that moves the liquid through the tiny spaces. Capillary action is how liquids move through tiny spaces without any external force. It’s like a secret superpower of liquids!

In our experiment, we’re using paper towels as the porous material for capillary action to occur. When we dip one end of the paper towel into the cup of colored water, the water molecules are attracted to the fibers of the paper towel (adhesive forces) and stick to them. The water molecules are also attracted to each other (cohesive forces), so they pull each other along the paper towel.

This creates a chain reaction, with the water molecules in the paper towel pulling the water molecules in the cup along with them. As a result, the colored water crawls up the paper towel and into the empty cup, moving against the force of gravity.

To make the capillary action more visible, we’re added different colors of food dye to the cups. When the water crawls up the paper towel and into the empty cup, it takes the food dye with it, creating a colorful pattern. We used primary colors (red, yellow, and blue) to demonstrate how colors can blend together to create new colors, which is a great way to teach kids about color mixing, but you can do this experiment using any colors you desire!

The end result is a gorgeously vibrant rainbow that your kiddos will be proud to have created!

Variations of Walking Water to Try

The best part about science experiments is that you can always change things up and try new variations. Here are a few ideas to experiment with:

Experiment with Different Liquids

Capillary action isn’t just limited to water – you can try this experiment with other liquids too! Try using milk, vinegar, or even soda to see how capillary action works with different types of liquids.

Try Different Types of Paper Towels

Different paper towels have different absorbency rates, which can affect how quickly the colored water travels through the paper towel. Try using different brands or types of paper towels and see how the results compare. You could even try using other porous materials, like a coffee filter or a piece of fabric.

Vary the Water Level and/or Paper Towel Height

Another way to experiment with this activity is to change the height of the paper towel or the water level in the cups. You could also try adjusting both variables to see how it affects the movement of the colored water. This can help you learn more about how capillary action works under different conditions.

Crawling Colors Printable Packet

Our printable packet includes everything you need to conduct the crawling colors science experiment with ease. The packet includes clear directions, a predictions section, a color observations chart, a K-W-L chart, and a recording results section, making it easy for kids to track their progress and learn as they go.

Our 7-page packet is perfect for homeschooling, classroom activities, or just a fun weekend project with your family. With easy-to-follow instructions and a variety of helpful charts and tools, our packet takes the guesswork out of conducting the crawling colors experiment, and makes it easy for kids to understand the science behind capillary action.

So why wait? Order our printable packet today and get ready to watch your kids have fun while learning about the amazing world of science!

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