Dr. Darlene Ingram ’91, assistant professor of chemistry and chemistry program coordinator, was recently invited to do STEM experiments with the United Methodist Central Summer Camp in Evansville, Ind. Dr. Ingram also brought along recent chemistry graduate Angelique Laizure ’22 to assist with experiments.
“The campers made chromatography butterflies, performed the magic milk experiment, and observed pH changes with radish coloring. At the conclusion of the camp events, I did a pH experiment using cabbage juice as a natural pH indicator,” Dr. Ingram explains.
To create chromatography butterflies, campers used markers on coffee filters. They observed the black ink separate into red, blue, and yellow. In the end, the filters were dried and with the help of a pipe cleaner, they were formed into butterflies.
The magic milk experiment was done with a simple dish of milk, a few drops of food coloring, and a drop of dish soap on a cotton swab. Because the soap is polar (oppositely charged) and the fats in the milk are non-polar (equally charged), there is rapid movement when milk and soap come in contact.
The skin of radish can be used as a pH indicator to color a picture pinkish-red. When the color on the picture is in contact with a weak base, the pink turns blue. With a strong base, the pink turns yellow. Under acidic conditions, the radish-colored picture will get deeper red.
The anthocyanins (colored water-soluble pigments) in purple cabbage can be extracted with boiling water. When different solutions are added, the result is a natural, broad-spectrum pH indicator.
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