Learn about chromatography with this simple science experiment! You only need a coffee filter or paper towel, water and a washable black marker. Kids will love to see the ink travel in this science experiment.
RELATED: Grow a Rainbow Experiment
Coffee Filter Chromatography Experiment For Kids
Kids will love seeing the black marker separate into different colors in this simple science experiment! You can use either paper towels or coffee filters, or try both to see what happens!
Here’s what you need for this activity:
- Paper Towel or Coffee Filter
- Washable Black Marker (we used Crayola)
- 2 Small Glasses or Plastic Cups
Watch The Full Video Tutorial Here
What is the Science
This science experiment is a great example of chromatography. Chromatography is the process of separating out a mixture of chemicals. In this experiment, you will see the black ink separate into different colors. If you ever get a paper with ink wet you would have seen the ink move across the page in streaks. In this experiment, you should see blue, red/burgundy and a bit of green come out of the black ink.
Capillary action makes the marker dye move up the paper towel or coffee filter. The water moves upward through the paper towel or coffee filter, lifting the washable dye molecules with it. Because the washable markers are water-based, they disperse in water.
Make it a Science Experiment
Set up a few different scenarios and hypotheses. For example, if you were to try this experiment without any dye, you would still see the water rising upwards towards the center of the paper towel.
If you were try this experiment with permanent markers it would not work. This is because the markers are not water-based (they are alcohol-based) so the dye in the marker does not travel with the water. You can also show that permanent markers will disperse with rubbing alcohol but not with water.
- You need absorbent paper towel or napkin – we used the brand Bounty
- You must use washable markers – make sure to check it’s washable as not all Crayola brands are washable
- Do not place the end of the paper towel or coffee filter too deep into the water or the dye will dissolve into the water instead of traveling up the paper towel
Chromatography Experiment Instructions
For the coffee filter experiment:
Draw a circle in the center of the coffee filter. Make sure you make it a thick circle with plenty of ink so that there is enough ink to move up the coffee filter.
Fill a cup with about 1/2 an inch of water, or just enough for the non-inked portion to touch the water. You don’t want the black marker to be submerged in the water.
Fold the coffee filter and place it in the water, tip side down.
Do not place the end too deep in the water or the dye may dissolve into the water instead of moving up the coffee filter.
The washable marker dye will slowly make its way up the coffee filter and the colors will begin to separate.
Unfold the coffee filter to reveal a beautiful design!
For the paper towel experiment:
Cut a paper towel down to a smaller length.
Fold over the strip of paper towel (so you have 2 pieces on top of each other).
Draw a thick line of black marker about 2 inches from the end of the paper towel. Make sure you use plenty of black ink so that there is enough to move up the paper towel.
Put about 1 inch of water into a cup.
Place the end of the paper towel in the cup of water. Prop the opposite end of the paper towel on an upside down cup to keep it upright.
The black washable marker dye will slowly make its way up with the water and separate into different colors.
We love how simple this science experiment is!
You can expand on the learning by testing with different kinds of markers – like a permanent marker or dry erase marker. You can also try our grow a rainbow experiment (for more capillary action) or our dry erase experiment!