Semipermeable Membrane STEAM activity

Share with your friends!

For New Year’s Eve this year, my family celebrated with dinner with neighbors, and a fun STEAM activity involving coffee filters and capillary action. We watched as color exploded on the coffee filter, creating our own (safe to use inside the house) fireworks. I wanted to use a different kind of coloring agent, so I thought we would try the same experiment, but using watercolors instead. But when the boys painted the coffee filters, the watercolors went straight through the coffee filter! I was reminded by my husband that coffee filters are semipermeable membranes, which is why they are used in filtration to make coffee. Semipermeable membranes allow for some molecules to pass through, and others not. A coffee filter holds back the coffee grounds, but water, flavor, and caffeine pass through the filter into our cups. I had an idea that would allow us to capture our coffee filter paintings through the semipermeable membrane coffee filter.

A beautiful STEAM activity using a familiar semipermeable membrane: a coffee filter! Kids will love their beautiful creations, while learning science!

Semipermeable Membrane Painting STEAM Actvity

Post contains affiliate links. Please see disclosure for more information.


Supplies for our semipermeable membrane art activity.

Coffee Filter Painting

STEP 1: Fill the small plastic paint cups with water, then add watercolors from tubes for desired colors. We chose red, yellow, green, blue, and purple.

STEP 2: Place a coffee filter on top of one sheet of watercolor paper. I also place a wipe-able place mat under the watercolor paper.

STEP 3: Paint the coffee filter using the pipettes and watercolors. Drop one drop of water color at a time, and watch how the paint spreads through the coffee filter.

Using pipettes to paint!

As I explained in another post, the paint moves due to capillary action. All three of my boys loved this part, and I loved watching them create!

Using just a drop of a paint at a time, my boys watch the paint spread on their coffee filters.  Capillary action in action!

My littlest one decided he wanted to push down all the bubbles that were made when he was dripping paint.

My littlest one decided to pop all the bubbles!

Here’s how their painted coffee filters turned out!

Final painted coffee filters!

STEP 4: Let the painted coffee filters dry completely.

STEP 5: Once dry, slowly pull the coffee filter away from the water color paper. My boys loved this part too! It was like watching them unwrap a present to see what was under the paper.

Pulling back the coffee filters after they dried!

Their final creations. So beautiful!

Our semipermeable membrane paintings!

You will notice the paint went completely through the coffee filter, and onto the watercolor paper. That is because the coffee filter is a semipermeable membrane. The filter allows the water, and the color pigment in the paint, to almost completely flow through the coffee filter, and onto the thick, watercolor paper.

Isn’t science beautiful?

3 Engineering Activities!

Image of book

Explore the fields of Mechanical, Chemical, and Electrical Engineers with this 3 day email course about engineers!

We won’t send you spam. Unsubscribe at any time. Powered by ConvertKit

Looking for other STEAM activities for you kids? Check some of my ones!

Easter Egg STEM Activity
Capillary Action Color Explosions!
Make a Rainbow using one of the Properties of Water
Appearing Snowflake: A Winter Activity for Kids
Painting Pumpkins with Paintballs: A Quick STEAM Activity
Paintball Forces Science Experiment