Paper Chromatography: These colors DO run

This activity is designed for students to develop good lab technique and learn about how molecules move through substances. Students will develop critical thinking skills during this activity. Students will use observation and other proper lab techniques while completing this activity. Students will learn the concepts of separation of molecules by size and polarity. Students will learn the meaning of chromatography, molecules and polarity.

This activity will be used in a high school Chemistry classroom, any level. This activity can be done with any class size. The time needed is one class period, 45-50 minutes. The necessary equipment is a variety of colors of markers, both water soluble and permanent, beakers and filter paper. If filter paper is not available, coffee filters can be cut and used. This activity can be done as an introductory inquiry activity and concepts can be taught after. This activity takes place after talking about atoms and molecules and their relative sizes. This activity can be adapted very easily for other areas and levels. Concepts can be taught before and this can be used as a follow-up activity.

For high school students, this activity should take place after talking about atoms and molecules and their relative sizes. Each lab group will need a beaker, filter paper and a variety of colors of markers. This lesson will be introduced with very little information given to the students. They will just be allowed to experiment and see what happens. After completing the activity, the students will answer the questions and we will have a discussion about what they saw happen. I will talk through any misconceptions the students have and work through them. Then I will show students a PowerPoint going into detail about paper chromatography and what it is used for. The following day as an extension of this activity, I will have students try to solve the mystery of the missing cat ransom note. They will analyze different black markers and compare it to a known sample and try to solve the mystery. This helps them to see how these techniques can be used in the real world. This activity is adapted from USAFA Department of Chemistry, Mini-Lab Unit 2-4: These colors DO run. Assignment handout (Microsoft Word 80kB Sep18 08) Paper Chromatography PowerPoint (PowerPoint 426kB Sep18 08)

It is important for students to know that the actual dot made on the filter paper with the marker should not be put under water as this will not allow the colors to move. This activity is different from what I have done is the past as it is a discovery activity. I usually introduce paper chromatography first and then let them play, and then do the ransom activity. It will be interesting to see how things will change, if anything.

Students will be assessed on their responses to the questions on the worksheet and contributions to class discussion.

The MN Academic Science Standards that are covered by this lesson are IIA7 - particle interactions, IIA8 - atom, molecule differentiation, IIA9 - element, compound differentiation.