Elmer’s Disappearing Purple Glue is a standard school supply in most K-12 classrooms. Many students are familiar with its bright purple color that disappears as it dries on their school projects.
The major constituent of a KoolAid or a similar non-carbonated soft drink will probably be either citric acid, malic acid, or a mixture of the two acids. Either of these two weak fruit acids provides a pleasant taste and an acidity level that makes the drink palatable.
A debate broke out among students about red velvet cake during a recent chemistry class. We were studying natural acid-base indicators, and a student claimed that cocoa powder was an acid-base indicator.
In Chemical Mystery #19,1 a yellow liquid is poured into a test tube, and the liquid turns red. When a white sold is added to the red liquid in the test tube, the liquid turns blue.
Classroom demonstrations have long been an approach used to convey information in chemistry courses. The intent is to help student learning by providing physical examples to illustrate concepts described in class.
