🌈 Grow a Rainbow - 5 minute Science Experiment Exploring Capillary Action

Amaze your kids with this simple grow a rainbow activity! This capillary action experiment allows preschool, pre-k, kindergarten, first grade, 2nd grade, and 3rd graders to learn about capillary action while having fun. This capillary action rainbow experiment makes science exciting and fun with a few simple materials and 5 minutes!

Capillary action experiment

Amaze your kids with this simple yet captivating “Grow a Rainbow” activity! This fun and educational capillary action experiment is perfect for preschoolers, pre-k, kindergarteners, and even first, second, and third graders. It’s a fantastic way to introduce young scientists to the fascinating world of capillary action while they engage in a hands-on activity that will leave them in awe.

With just a few simple materials that you probably already have at home, you can create a spectacular rainbow right before their eyes—it’s as easy as 1, 2, 3! In just 5 minutes, your little ones can witness science in action, as colorful water travels up the paper towels like magic. Not only is this experiment visually stunning, but it also provides a wonderful opportunity for children to explore and learn about the science behind capillary action in a fun and engaging way.

This activity is not only entertaining but also fosters curiosity and encourages kids to ask questions about how things work in the natural world. It’s the perfect blend of fun and learning, making it an ideal choice for a weekend project, a day off from school, or even a science-themed playdate!

We have lots more science activities for kindergarten including this epic ice cream volcano experiment and using science to color flower activities.

capillary action rainbow experiment

All you need to try this easy science experient for kindergartners are a few simple materials you already have on hand:

2 glasses
water
washable markers
paper towel

Grow a Rainbow

Now you are going to make a block of each color, in rainbow order as shown above, on each side of the paper towel. You want it to be a solid block in the same order as the other side, so color it in well. But the middle section is all white.

HINT: The markers must be washable markers. In other words they are water based and will move when they come into contact with water for our experiment. Permenent markers will NOT work for this experiment.

Rainbow Experiment

Now you will need two glasses filled at least 1/2 full with water. You want to space them so that your paper towel reaches both sides. The colors should just barely touch the water. If you put too much of the colors in the water the colors will move to the water instead of flowing towards the other side of the rainbow.

Walking Water Science Experiment

Almost immediately you will notice the colrs are starting to move towards each other.

Spring Science Activities for Preschoolers

Continue to watch as the walking water experiment continues to unfold very quickly in front of your eyes. As the water travels up the paper towel, it will take the colors with it.

Spring Science Experiment

Right before your eyes you will have grown a rainbow! Not only is this a pretty science experiment perfect for spring or summer, but it teaches a scientific principal too!

Capillary Action for Kids

This simple, beautiful experiment teaches the principal of capillary action. Capillary action is the name of the process that moves liquids up through a solid (paper towel). This moving of water is how plants drink. In our experient the moving water took the washable dye molecules with it because they are water based and dispersed in the water. 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.

Kindergarten science experiment

This pretty science experiment takes less than 5 minutes and is super quick to clean-up. Simply throughout the paper towel (or dry it outside for a pretty decoration). Dump the water down the drain or outside on the lawn and wash out the canning jars.

Science activities for kindergarten

We had our paper towels too far in the water this time we did this experiment. Although it still worked, while the water molecules were traveling up with the dye, the dye under the wtaer was also dispersing and coloring the water. Ideally just put the tip of the paper towel touching the water for the best, quickest, and most reliable results with this colorful science experiments.

Grow a rainbow in less than 5 minutes! This SIMPLE spring science experiment teaches about capillary action with pretty walking water science experiment.