Name of Activity

Paper Chromatography




chemistry, testing, chromatography, polarity, solvent



Grade Level

4, 5


1 Hour

Brief Description

Students will use chromatography techniques to identify the writer of a secret note. One suspect is a computer scientist notorious for writing on whiteboards with Expo markers and the other is a ecologist notorious for labeling sample bottles with Sharpie markers.

Be sure to check with your teacher before bringing acetone into the classroom!!

Learning Goals:

introduce students to chromatography and chemical engineering


paper cups – 2 per group (NOT POLYSTYRENE!) + extra for mess ups

strips of coffee filter paper (4 strips per group)+ extra for mess ups

One sharpie marker

One expo marker




Cut coffee filter paper into strips

Knowledge Background

Knowledge of the properties of water and acetone, knowledge of polar vs non polar and its influence on the results


1. Introduce the problem (identifying the writer of the note) and brainstorm possible solutions. The solution we will be using today is testing the ink to see what type it is.

2. Split the students into groups (pairs ideally). Distribute the cups and filter paper.

3. Demonstrate how to label the filter paper and make sure every student does it right. Each paper should be labeled either SW, SA, EW, or EA, for sharpie-water, sharpie-acetone, expo-water, expo-acetone.

4. Have one person in the group take the sharpie filter papers and get them dotted with a sharpie marker from a teacher, and another person get the expo filter papers dotted with acetone.

5. Before distributing the water, instruct the students to dip only the water filter papers in the cup and to make sure the dot of ink doesn’t go below water level. Once you fill one of their two cups with about 1 centimeter of water, have them hold the paper until the ink stops traveling up the page or after about a minute. Have the students record the results.

6. Discuss the results and if any changes  occurred, and have the students suggest improvements to the test that would allow for better results. Go over the properties of acetone and water and their polarity and why changing the solvent might lead to better results.

7. Repeat step 5 with acetone, but before distributing the acetone, make it clear that acetone they should not put acetone in their mouths or inhale it directly, and that if anyone feels nauseous that they should tell you right away.

8. Compare the results with acetone from the results with water. Discuss why they might be different.

9. Cut off a strip of the note so that a bit of ink is near the bottom. Conduct step 5 with the note in front of the class. Observe the results and have the class make a conclusion about who wrote the note, based on their previous results. Talk about why testing is an important part of the redesign process, and what they could do to improve the test.


Adding extra solvents to test or extra markers as a challenge.


Using vinegar instead of acetone, or different markers (but make sure to test the markers with the solvents beforehand)

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