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This experiment is so much fun because it’s a blend of art and STEM, or STEAM, in one beautiful experiment. Today, we’re making coffee filter flowers!
This experiment demonstrates capillary action (how liquid moves through narrow spaces), chromatography (the process of taking some kind of mixture and using a solid or liquid to separate that mixture into its different components), and color blending by coloring a coffee filter and dipping it in water to see how the colors move.
Ready to bring out your inner artist while learning some cool science? Let’s get started!
How to make the Coffee Filter Flower Chromatography STEM experiment
Supplies you will need
For this experiment, you’ll need:
Before you start
As you can see in the pictures, fingers can get quite messy in this experiment. If you’re concerned about that, you can wear a pair of gloves to keep staining at a minimum.
Instructions
Here is how to do this experiment with your child:
Step 1: Use markers to color the coffee filters
Cut a piece of foil that will completely fit under the coffee filter. Open the coffee filter and flatten it on the foil.
Use washable markers to draw on the coffee filter with whatever colors you would like your flower to be. We chose to color ours all of the colors of the rainbow. The more color, the better!
Step 2: Spritz the colored coffee filter
Spritz around the edges of the coffee filter and a few in the middle. It doesn’t have to be completely saturated! We actually did a couple of rounds of spritzes until we achieved the look we wanted, waiting for the filter to dry in between spritzing rounds.
We also experimented when the coffee filter was still wet by sliding the coffee filter around on the foil. It helped to blend the colors a little!
Step 3: Attach the pipe cleaner and pencil
Once the coffee filter is completely dry, grab the middle of the coffee filter and fold up the sides to make it look like a beautiful flower.
Offset the pipe cleaner a little so you have a longer side and shorter side, pinch the bottom of the flower, and start twisting the shorter side of the pipe cleaner around the base to hold it in place.
Don’t twist it too many times, because we’re going to use it to wrap the longer end of the pipe cleaner around it and the pencil (see pictures).
Finish the flower by completely wrapping the longer end of the pipe cleaner around the pencil.
Step 4: Observe
Every marker brand is different, but some markers will start to separate the colors and hues the manufacturer used to make that color. The process of the separation is chromatography (see the “STEM behind it” section below to learn more about it).
For example, the purple marker we used separated on the edges to a pinkish color, and the black marker separated into a bluish color around the edges.
One fun experiment would be to see how many of your markers do the same thing!
The STEM behind the Coffee Filter Flower Chromatography experiment
This experiment teaches:
- Color blending
- Capillary action
- Chromatography
How it works
This experiment demonstrates capillary action, which is how a liquid moves through narrow spaces, as the water moves through the coffee filter’s tiny fibers.
As the water travels through the filter, it moves the pigments from the markers along. Since different pigments have different solubilities and attractions to the coffee filter, they separate at different rates, which is called chromatography.
It’s also great for demonstrating and experimenting with color blending, by showing what pigments different colored markers are made from.
Color blending
Teaching about color blending by having your child memorize that red and blue make purple isn’t quite as effective as having them witness the color blending first hand!
This experiment teaches about color blending by using markers for color and water for dispersing. When the water is added to the coffee filter, the secondary colors will begin breaking off into their primary color mixes. When we add water to the primary colors, they stay the same.
If you decide to add multiple colors to your coffee filter, you will see the colors start to mix and blend, creating new shades and hues.
Capillary action
Capillary action is so easy to demonstrate using this experiment!
Capillary action is how a liquid moves through narrow spaces, like the fibers of a coffee filter or the stem of a flower, without help from gravity. It sometimes even works against gravity.
As you dip the coffee filter in the water, have your kids observe how the water travels up the coffee filter’s tiny fibers. In this case, the water molecules are attracted to the fibers of the paper (adhesion) and are also attracted to each other (cohesion).
Those forces pull the water along the coffee filter, even opposing gravity!
Chromatography
Chromatography sounds complicated, but it’s actually really simple: it’s the process of taking some kind of mixture and using a solid or liquid to separate that mixture into its different components.
Our experiment today gives a good introduction to this concept!
The colors in our markers have different colored pigments in them. For example: the green marker is composed of different colored pigments, like yellow and blue, that make it green. Those different colored pigments travel at different rates through the coffee filter, depending on their size, solubility in water, and attraction to the coffee filter paper. Those things together cause the colored pigments to separate on the paper!
The water that we apply to the tip of the folded coffee filter moves up the paper because of capillary action (the section above).
One fun experiment is to try the same colored markers from different brands. If those brands do not create their markers exactly the same, you will be able to see different colored pigments result from adding water to the coffee filter and watching them travel.
More experiments about colors to try out with your child
- Making Rainbows: A simple prism experiment
- Rainbow Rain Science Experiment (the first experiment on Small Step for STEM!)
- Rainbow Rivers: Unveiling the Science of Capillary Action with Colored Water Bridges
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