STEM Activity: Marker Mystery

This hands-on STEM activity is a great way for students to explore the science of chromatography!

Materials Needed

• Coffee filters cut into fourths
• Four assorted brands of water-soluble black markers
• A small bowl filled with water
• Ballpoint pen

At-Home Instructions

1. Cut your coffee filters into strips (approximate dimensions: 2 inches wide at the top and about 1 inch wide at the bottom).
2. About two finger widths from the bottom of the strip, create a circular dot. Mark each strip with a different brand of black marker.
3. At the top of the strip, use a ballpoint pen to write the brand of the marker used on that strip.
4. Have your child slowly dip the bottom of each filter strip into the water so that the black dot is above the water line.
5. Watch as the water travels up the filter. Once it is wet enough, your child will be able to lay the filter strip over the edge of the bowl and begin working on the next strip.
6. Once the water has spread to the top of each filter strip, place them flat on a table to dry.
7. Explain to your child that they have just created chromatography strips! Even though each marker is black, they all contain shades of other colors. Ask them what different colors they are able to observe.

Educators: Use this activity in the classroom with these modifications

Split your classroom into groups and give each a unique color to explore. By creating chromatography strips for different colors, see if your students are able to find patterns. Do brighter colors produce similar chromatography patterns? What about darker colors? This is a great activity to include if you are teaching a unit on color, and it can be modified to best fit your needs.

What are we learning?

Using chromatography, children can uncover hidden colors. While each of the markers appears to be the same (they are all black), they’re not — each has its own unique characteristics. During the 19^th century, a Russian chemist named Mikhail Tsvet developed a way to separate colors of a substance to learn more about it. He called this process “chromatography,” which means, “color writing.” This phrase is a combination of the Greek words “chroma” (color), and “graph” (write). Today, chromatography is used in many different fields, ranging from testing for pesticides and contaminants in food, to identifying sources of oil pollution in the ocean.