Finding Red

In this chemistry challenge, learners systematically investigate which combination of four solutions produces a deep red color. The four solutions are iron(III) chloride, ammonium thiocyanate, tannic acid, and oxalic acid. Background information explains that it is the iron ions in solution combining with ions from the other solutions to create the different colors. After learners discover the different colors, they are encouraged to add a third solution to see if the color can be changed, an example of how chemical equilibrium can be shifted. This activity may take a bit more time with younger learners. For safety reasons, adult supervision is recommended and can be conducted as a demonstration for younger audiences.