Kaining Mao and Yi Wang Teach Chemistry with Cabbage

As scientists, we are eager to engage with the public, especially with the younger generation, by sharing our knowledge in a way that is both accessible and motivating. Sharing the thrill of scientific exploration can spark curiosity and a passion for learning among children. Fortunately, as STEM Ambassadors, we received comprehensive training to design and implement public engagement events. During a brainstorming session with Andrew George, the STEMAP mentor, we devised a plan to organize a workshop aimed at young children, featuring hands-on activities. This initiative eventually guided our focus toward collaborating with the 4-H group in Ithaca.

To enhance our interaction with the children, we established a connection with Beth Rhoades, who is not only a professor at Cornell, but also the leader of S-TEAM within the 4-H group in Ithaca. Through our discussions, we learned that the S-TEAM activity consistently attracts about ten students (8–13 years old) to its monthly activities. We were informed that the group typically convenes on the third Thursday of each month for a one-hour session that includes various scientific activities. Knowing that the students had previously explored subjects like building circuits and coding, we decided to focus our workshop on Chemistry. Inspired by Victoria Russell during the CSOE–STEMAP in-person training, we planned a workshop that would use red cabbage as an acid–base indicator. Recognizing that certain students had limited opportunities to visit a university campus or laboratory, we reached out to Department of Chemistry and Chemical Biology at Cornell. This collaboration allowed us to host our workshop in a teaching lab, giving the students a memorable experience in a real university setting.

On September 21st, 2023, the workshop unfolded at Baker Laboratory at Cornell, with the participation of 9 children accompanied by their parents. Understanding that the concepts of acidity and basicity might be challenging for children to grasp, we initiated the session by relating acids and bases to familiar tastes. The students shared their experiences, mentioning the sour taste of vinegar and the accidental bitter taste of soap water. This led us to discuss that while not everything should be tasted for safety reasons, there are tools like indicators that help us identify acidic and basic substances. Then, we introduced red cabbage juice as an easy-to-use and accessible indicator, launching into a hands-on activity to explore the principles of acidity and basicity with the participants.

Following the introduction, we handed out red cabbage leaves to each participant, instructing them to mix the leaves with water, squeeze out the juice, and dispense it into six transparent cups with Andrew Ressler’s support. Next, we guided the students to add different substances—lemon juice, vinegar, baking soda, Sprite, and soap water—to five of these cups, reserving one cup as a control. We encouraged the students to observe and record the color changes. As anticipated, acidic substances like vinegar, lemon juice, and Sprite changed the indicator to shades of red or pink, whereas the basic substance, baking soda, turned it green. After collecting their observations, we explained the science behind these color changes. To deepen their understanding of acidity and basicity, we introduced three types of pH indicator papers commonly used in labs. By demonstrating how to use these papers, we divided the children into three groups, each experimenting with one type of paper, noting the color changes observed, and comparing the results with each other as well as with the red cabbage experiments. This comparative approach was designed to reinforce their understanding of acidity and basicity.

Finally, to enrich their visit to Cornell, we took the students on a short tour of the chemistry research lab, offering them a glimpse into the realm of scientific investigation. As a parting gift, we gave each student some leftover red cabbage leaves, encouraging them to design and conduct their own experiments with different substances once they were back home. This extension of the learning experience aimed to foster a continued curiosity about science and experimentation beyond the confines of the workshop.

Our survey revealed that all participants gained a comprehensive understanding of acidity and basicity, with most of them finding the activity enjoyable. Interestingly, the children found the tour of the building intriguing, particularly when shown large equipment like the glove box or NMR facilities. However, the task of accommodating a wide age range of participants with varying levels of prior knowledge emerged as a challenge. To make future workshops more effective and engaging, it is essential to either adjust the materials presented or to consider focusing on a narrower age range. This approach will allow for the content to be better tailored to the participants’ needs. The insights gained from this feedback as well as those from Laurie Lopez and Nina Houghton, observers from Inverness Research, are invaluable for refining the workshop in future iterations, ensuring its ongoing enhancement.