Colorful Capillary Action
Discovery Place Science
Capillary action is when water adheres to the walls of something and moves upward despite forces of gravity. A great example of capillary action is how water moves from the roots of a plant, up to the stem then into the leaves and flowers.
In this activity, learners can demonstrate the gravity-defying action while creating a colorful piece of art along the way.
This activity is best suited for students in elementary school grades. It includes about five minutes of preparation and 30 minutes of learning.
- Coffee filter (Note: Paper towels or tissue paper could be used instead of coffee filters. Something that is more absorbent works best. If using materials other than a coffee filter, for best results cut it into a circle.)
- Cup or glass
- Water-based markers
- Fill a cup or glass with one inch of water.
- Fold the coffee filter in half and crease it.
- Fold it in half again and crease it. The coffee filter should now look like a fan or an ice cream cone.
- Take a marker and draw a line two inches from the pointed end of the coffee filter. Open the coffee filter and extend the line to draw a circle that is about two inches from the tip. This is the bottom of the coffee filter. Make sure all art is done above this line.
- Pick three or four of your favorite colors and start drawing! Lines, squiggles, circles, squares, triangles. Be creative!
- Once the artist is finished, place the bottom (pointed end) of the coffee filter into the cup.
- Feel free to do one, two, five, ten more! Since coffee filters usually come in packs of dozens (if not hundreds) take the opportunity to do more than one, if you like.
- For the next 10 minutes, observe what happens. If the colors are moving quickly, you can take the filter out sooner, lay it flat to dry. What did the water do? What happened to your art?
Demonstrating capillary action, as the water goes up the coffee filter it will carry the different colors different distances, leaving you with an amazing piece of art.
How to adjust for younger and older learners
For younger learners, try drawing with markers on a paper towel, laying it on a flat surface like a plate and spraying it with a fine mist from a spray bottle to scatter or separate the colors.
For older learners, experiment with different types of paper, exploring how different absorbent materials change the effect of the markers. Study different colors, noting which moves the furthest distance and which travels the shortest.