STEM events for kids are so much fun. Teaching them about colors, capillary action, and chromatography results in making flowers like this one. Watching their eyes get big as they watch in real time as the pigments in the ink pull apart and flow to the edge of the little filter paper is extremely satisfying.
@30pics4jackiesdiamond the shape of the filter paper plays a little part in it. The design that is drawn around the center also plays a part. The water wicks up (this is capillary action like how plant roots draw up water) at the very center and spreads out pushing the inks with the spread. Lighter pigment molecules push out the farthest and the fastest. Using colors like brown, black, and purple have their component colors pulled apart making very interesting designs. You can see in my photo the examples showing how the filter was marked up and the resulting flower beneath.
