Capillary action is an exciting part of science and can be hands-on and engaging for kids. Learn what capillary action is with our simple definition below. Check out these fun science experiments demonstrating capillary action at home or in the classroom. Easy to do science experiments at the tip of your fingers.
Capillary Action Examples
Here are some fun ways to demonstrate capillary action. Plus, all you need is a handful of common household supplies. Let’s play with science today!
Celery Experiment
There’s nothing better than science in the kitchen! Set up a celery experiment with food coloring to show how water travels through a plant. Perfect for kids of all ages!
Chromatography
The uptake of water in paper using markers is a fun and simple way to explore an example of capillary action.
Color Changing Flowers
Grab some white flowers and watch them change color to demonstrate capillary attraction in plants.
Coffee Filter Flowers
Explore the colorful world of STEAM with these coffee filter flowers. Here’s an alternative way to make coffee filter flowers too!
Grow A Rainbow
A fun and colorful experiment that uses a paper towel, markers and water to demonstrate the process of capillary action.
Leaf Veins
Collect some fresh leaves and observe over a week how water travels through the leaf veins.
Paper Towel Test
Compare different brands of paper towel to find out which one is the most absorbent and what factors affect capillary action.
Toothpick Stars
Here’s a great example of capillary action that doesn’t use plants. Make a star out of broken toothpicks by only adding water. It all happens because of the forces in capillary action.
Walking Water
Explore the capillary action of water with this classic science experiment. Walking water is a colorful and easy-to-set-up science experiment that moves water through paper towels via capillary action.
Water Absorption
A simple water experiment for younger kiddos. Add colored water to cotton pads and observe how they absorb the water through capillary action.
What Is Capillary Action?
Here is a simple capillary action definition to share with kids. Capillary action is the ability of a liquid to flow in narrow spaces without the help of an outside force, like gravity.
Try This: Capillary action looks a bit like magic! Imagine you have a tiny straw, so tiny that you can’t even see it. Now, dip one end of the straw into a glass of water. What do you think will happen? The water inside the straw starts to climb up all by itself.
This happens because of a special force that water has called ‘capillary action.’ It’s like water’s secret ability to climb up things. The water molecules love to stick together and stick to other things, like the walls of the tiny straw. These sticky forces pull the water up!
You can see capillary action when you look at a piece of tissue or paper towel dipped in water. The water seems to travel up the paper, making it wet.
Plants and trees couldn’t survive without capillary action. Think about how tall trees can move a lot of water so far up to their leaves without a pump of any kind. It also helps our bodies by moving water through tiny blood vessels.
How Does Capillary Action Work?
What is the physics behind capillary action? Capillary action happens because of several forces at work. This includes the forces of adhesion (water molecules are attracted and stick to other substances), cohesion, and surface tension (water molecules like to stay close together).
Water’s capillary action happens when its adhesion to the walls is stronger than the cohesive forces between the water molecules.
What is capillary action in biology? Plant capillary attraction happens when water travels through the roots and narrow tubes in the stem before moving to the leaves. As water evaporates from the leaves (called transpiration), it pulls more water up to replace what has been lost.
Also, learn about the surface tension of water!
Printable Science Projects For Kids
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