Observations and results
Did you find that green and brown M&Ms are each made up of two dyes whereas blue, yellow, and red M&Ms only use one dye? Did some of these dyes match the ones from the red, blue and green food coloring strips?
You may have seen that blue food coloring liquids you tested, on the other hand, has blue and red dyes; red food coloring has two different red dyes; and green food coloring uses a blue and a yellow dye (the yellow may be covered by the blue dye, making it appear green; and all of this can depend on the exact food colorings used). Looking at the ingredients list on the packaging can help you determine exactly which government-certified Food Drug and Cosmetic Act (FD&C) dyes these are. Blue M&Ms use one of the same blue dyes and red M&Ms share one of these red dyes. (You can figure out which by looking at the ingredient list on their package.) If you tried brown M&M's, you probably saw that they contain a red dye (the same one as red M&M's) and a blue dye. Green M&M's also use two dyes, a yellow dye and a blue dye, although the latter may be too faint to easily see. Yellow M&M's use a single yellow dye.
Throw away the paper towels and wash the bowls and pots. If you want, you can eat the wet M&M's candies!
More to explore
Capillary Action, from W. W. Norton & Co.
Paper Chromatography Science Background, from Florida Institute for Human & Machine Cognition
Overview of Food Ingredients, Additives and Colors, from the U.S. Food and Drug Administration
Candy Chromatography: What Makes Those Colors?, from Science Buddies
This activity brought to you in partnership with Science Buddies