Chromatography-Teacher Edition

Chromatography-Teacher Instructions

Chromatography is the physical separation of a mixture into its individual components. In this activity, students will use filter paper to create a chromatogram that will show several black markers separated out into the individual colors that it contains.

Question: Which of your black pens matches the “mystery mark”?

Materials:  Filter paper cut into strips approximately 4-5” long (each group needs 4 strips)  4 different black markers per group– one of these should be a permanent marker, the other three should be water soluble (each a different brand)  Large clear cups – 1 per group  Popsicle sticks – 1 or 2 per group  Strips with Mystery Marker on them – 1 per group

DAY BEFORE:  Run a chromatography strip for each of the markers ahead of time so that you know which strip matches which markers.  Choose the one that is the most distinct and this will be your “mystery marker” for tomorrow.  Make up 1 strip for each group from the “mystery marker” by placing a thin line across the strip, 1 inch from the bottom. Students will then be testing this “mystery marker” strip and comparing it to their 4 marker chromatogram strips.

Background Information: Chromatography is the process of physically separating a mixture by passing it through a stationary phase. Even though the ink from black markers looks the same when you write with them, they are made up of different color combinations to create their black ink. In this lab, students will use filter paper to separate black marker (water soluble) into its individual color components. As the water travels up the filter paper, the marker will travel with the water. The heavier, slower particles will be more towards the bottom of the paper, while the smaller, faster particles will be up near the top of the paper.