December 16th, 2020
Experiment leads: Jane and Zixue
Students and volunteers explored the concept of a chemical reaction through an introductory presentation and an experiment. Zixue and Jane introduced chemical reaction, acid and base, and pH scale with a short presentation that encouraged students to think about chemical reactions that they have encountered in their daily lives (great examples brought up by the students including fireworks, baking, etc.). The class was then divided into breakout groups with 2-3 students and volunteers per group for experimental demonstration. The experiment was designed to be safe for conduction at home and experimental supplies including cranberry juice, grape juice, water, baking soda, papers, cotton swabs were delivered to students prior to the SFA visit. In the experiment, volunteers guided the students to first draw pictures or write messages with mixtures of baking soda and water on a piece of paper. While waiting for the paper to dry, SFA members and students explored more examples of chemical reactions in life and discussed the acid and base they used which are juices and baking soda, respectively, in the experiment. The message disappeared after the paper was fully dried. To reveal the message, students and volunteers used a new cotton swab that was dipped in different juices and painted over the invisible painting/message on the paper. The re-appearing of the message was rationalized as a chemical reaction taking place between basic baking soda and acidic juice, resulting in changes in the color of the indicator present in the juice. Students enjoyed the experiment (though a bit shy over Zoom) and showed very nice pictures/messages they drew.
