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How to Investigate the Dyes Present in Permanent Markers

Chromatography is the study of colors. This study often involves analyzing the different colored dyes used to make inks. Companies don't make specific dyes in every color and nuance, so marker producers have to experiment with color combinations to get the shades they want.

According to the Museum of Science and Industry, forensic scientists use chromatography to compare the ink in documents from suspects to popular ink brands. Localizing the ink used helps narrow where the criminal might be. You can learn this technique at home with your children.

Things You'll Need

Scissors
Coffee filters
Permanent markers: several colors
Water
Disposable plastic cups
Toothpicks

Instructions

- 1
  Cut several coffee filters into three-inch long, one-half-inch wide strips with a point at one end. Dot the point of each slip of paper with a different permanent marker. Use different colors to make things more interesting.
- 2
  Add about one-half-inch of water to the bottom of several disposable plastic cups. The water is a solvent that will wick up the coffee filter paper and expose the ink colors.
- 3
  Poke a toothpick through the blank end of each paper slip. Place each toothpick across the mouth of one of the cups. The tip of the paper should sit in the water.
- 4
  Let the paper soak for about 10 minutes.
- 5
  Check on the paper. The water should pull each ink dot into a long line of rainbow colors. Inspect each dot to see what color combos create your favorite markers.

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