In this episode, Mark and Katherine demonstrate chromatography using a coffee filter.
EDIT: I corrected a misspelling with the enunciated version of “chromatography” in the original video.
One question that we don’t address in the movie is why the black ink doesn’t appear to separate like the green ink did. CJ suggested that the green ink separates because it isn’t a primary color, and asked if red or blue would have acted like the black does.
CJ also thought it would be cool if we had several color spots around the coffee filter, had them separate, and then see if they would remix near the top. I thought that might be a cool way to mix science and art.
- "Chemistry for Every Kid" by Janice VanCleave, Copyright 1989 by John Wiley & Sons, Inc. Experiment #72, "Rainbow Effect"