Capillary Action Science Experiment

Your kids are going to be blown away by this fun, colorful science experiment  that helps kids understand capillary action.
Capilalry Action Science Experiment for Kids - This is such a fun way for kids to explore and learn with a hands on science project for toddler, preschool, prek, kindergarten, first grade, 2nd grade, 3rd grade, 4th grade, 5th grade, 6th grade. EASY and QUICK to do (kids activities, summer activities for kids, homeschool, summer science)

Capillary Action

Here is what you need to do for this quick and easy-to-replicate science experiment.

Start out by putting 7 glasses on the counter. Fill glasses 1, 3, 5, and 7 most of the way up with water.
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Now add food coloring to the glasses:
  • 5-10 drops of red food coloring to glass 1 and 7
  • 15 drops of  yellow food coloring to glass 3
  • 5-10 drops food coloring to glass 5
colorful science expeirment

Here is what your set-up should look like.

walking water science experiment

Now take a paper towel and fold it in half width wise, fold it again, and again, and again. Now put one side of the folded paper towel into one glass and the other side of the paper towel in the next glass. Repeat with the remaining cups.

walking water science project

Now comes the fun part! Watch capillary action in motion as the water climbs up the paper towel.

capillary action science experiment for kids

Capillary action is the process in which a liquid moves up something solid, like a tube or into a material with a lot of small holes. This happens when 3 forces called cohesion, adhesion, and surface tension work together. Water molecules are considered cohesive (sticky to each other) and they adhere (stick) to the paper towel. As one water molecule moves up the paper towel it pulls the other molecules with it. The molecules pull each other along like a drawstring.

Notice how the water has walked or moved along the paper towel. 

Ask your kids to make a prediction on what is going to happen next! You can always direct their answer to help them to see the yellow water and the blue water are moving into the same cup. What do yellow and blue make?

color mixing science experiment for kids

How cool is that?! The cup that had nothing in it is now equally filled with the ones on either side. The water stops walking when the water is at the same level next to it. 

preschool science experiments

Here is what you end up with - a beautiful rainbow of colors that walked and mixed by itself  while your kids observed capillary action first hand!

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Beth Gorden
Beth Gorden

Beth Gorden is a homeschooling mother of six who strives to enjoy every moment with her kids through hands-on learning, crafts, new experiences, and lots of playing together. Beth is also the creator and author of 123 Homeschool 4 Me where she shares 1000+ free printables, creative homeschool lessons, crafts, and other fun ideas to help preschool and homeschooling families have fun while learning and exploring together.