In this simple chemistry activity (page 1 of PDF under SciGirls Activity: Colorblind Dogs) about acids and bases, learners will mix a baking soda and water solution and use it to paint a message on a sheet of white paper. Once the paint has dried completely, learners reveal the secret message by painting over the entire sheet of paper with grape juice. Relates to the linked video, DragonflyTV: Colorblind Dogs.