science for tinies: chromatography part I

[psocoptera]

Project: Can We Unmix Colors?
Materials: water, art paper, construction paper, food dye
Explanatory details: This experiment is a work in progress! Today was a partial success but I definitely want to run it again and improve it. For our first try today, I spotted food dye in four "neon" colors onto strips of two different kinds of paper, construction paper and paper from a drawing pad labelled as suitable for sketching or watercolor. I bent the strips to hang them over the sides of a four-chambered former hummus container, so that each color of food dye had its own compartment, which was good because right away one of the pinks fell in and dyed the water red, and not long thereafter the green-dye construction paper soaked up enough water to pull *it* down into the water and dye it green.
How did it go: The "art paper" turned out not to wick at all, but the construction paper did - slowly enough that Junie had long since lost interest and been provided with ducks, but we reconvened to inspect our results. And in fact as the dyes had spread out up the paper, they had successfully separated somewhat! We could tell that the blue had just one color in it, blue, but the red seemed to have two parts, a red part that had moved quickly and a more magenta part left behind, and, best of all, the purple seemed to have *three* parts, the fast-moving red, blue behind it, and the left-behind magenta.
Things we talked about: We can see how the purple dye is made of red and blue dyes, which makes sense, because red and blue make purple.
What Junie got out of it: This one was definitely more for me than for her. She enjoyed seeing the water turn colors when the dyes got into it, and she gamely looked at the strips and discussed what we saw, but I didn't even try to get into an explanation of what was going on. Maybe next time? I'm curious to try it again with paper towels, to see if we can speed it up while still getting separation, and to try hanging the strips in a more secure fashion, maybe from paperclips in glasses.

Comments

[gannet.livejournal.com]

Steve Spangler has a video on YouTube which I think uses coffee filters and a black marker to do this. Would you like me to track more info down? Steve Spangler has a lot of good things to try which he labels science, though he doesn't go into controls or hypotheses or anything like that. It is a bunch of good stuff about how the world works, though,so perhaps I can forgive the lack of the Scientific Method. :P.

[gannet.livejournal.com]

aHA: http://www.stevespanglerscience.com/experiment/is-black-black

[psocoptera.livejournal.com]

Thanks! Although part of the fun for me is trying to come up with ideas and then figure out whether/how we can do them, so I probably won't actually watch this.

At least some inks are going to separate better with a solvent other than water - I really don't want Junie to get the idea that it's fun to play with stuff from The Locked Closet Of Cleaning Supplies where we keep the isopropanol and such, so I will probably keep working on the food dye and water combo for now. (Could also try vinegar, I suppose, although we add that when we dye eggs to help the dye *stick*, right, so it seems counterintuitive here?)

[gannet.livejournal.com]

>part of the fun for me is trying to come up with ideas and then figure out whether/how we can do them

That makes sense.

I know that vinegar helps certain dyes stick to proteins but not to other things, so it might be worth a try? Unless you think it would confuse Junie.