ctl logo

Dr. Christopher Vicente Hsin-Hung S. Chen

Lecturer in the Discipline of Chemical Engineering

Dr. Chen teaches both undergraduate and graduate courses and oversees the Masters of Engineering program for the Chemical Engineering Department in The Fu Foundation School of Engineering and Applied Science (SEAS). With the shift to remote teaching in Spring 2020, Dr. Chen had to rethink how best to motivate first-year students to learn about and practice chemical engineering concepts for their chemical engineering design project in the foundational SEAS course, The Art of Engineering. Dr. Chen met the moment by co-developing with Dr. Scott Banta, Professor of Chemical Engineering, a remote, hands-on, and low cost sourdough lab module for first-year engineering students. Read on to learn more about what Dr. Chen did in his course, what lessons and experiences he’s carrying forward, and the advice he has for other instructors at Columbia. 

Leverage Students’ Personal Experience

During COVID-19 lockdowns in the midst of the pandemic, certain hobbies that people could engage in while confined to their homes grew in popularity. One such hobby was the baking of sourdough bread. Drawing on this newfound interest in making sourdough bread, I realized that having students grow and analyze the activity of sourdough starters could form the basis for them to model a chemical process using material balances and reaction kinetics concepts, as well as engage in experimental design and troubleshooting. I knew it was important for this project to be very low-cost and involve only non-hazardous materials that would be easily accessible to students. For the first iteration of the project, we designed the activity around materials that students were likely to already have in a standard residential kitchen, so that any student expenses for the six-week project would amount to less than $5 in total. More recently, we’ve lowered the costs to students even further by distributing to them most of the necessary materials, so that students only need to provide water and an empty bottle.

Give Students Autonomy to Design Their Own Experiments

Though sourdough starters are typically inoculated from the baker’s hands and the local environment, starters can be inoculated from any source of bacteria and yeast (e.g., most food and drink). As such, I encouraged students to source microorganisms from fresh and fermented foods that they were interested in exploring and had easy access to during the lockdown. For example, one of my students from South Korea used kimchi as their source for microorganisms. Some students used yogurt with live cultures, while others tried sediments from wine. I had students compile and share their data with each other so they could analyze differences in carbon dioxide formation based on their inoculate sources. Now that we’ve returned to in-person teaching, students are still welcome to bring in their own materials (or request materials from our department) to design their own experiments, such as selecting different light sources, inoculation sources, and alternative liquids to grow sourdough in. Students appreciated the opportunity to explore what they each found interesting, which motivated them to sustain their sourdough starters throughout the six-week experimental module.

Embrace Inquiry-Based Lab Instruction

Despite the first iteration of this sourdough lab being taught remotely and with an inquiry-based approach, students responded positively to it. I surveyed my students that semester of Fall 2020, and almost all the students who responded reported that they learned a considerable amount and ranked the lab as excellent overall. While I initially wasn’t sure how students would respond to the open-ended nature of the experiments, by the end of the course, about half of the students I heard from shared their appreciation for this aspect specifically.

Advice for Instructors and the Future of Teaching at Columbia 

Challenge seeming contradictions.

The pandemic challenged me to reconsider whether chemical engineering labs can be taught remotely and still be hands-on. It was only when I accepted and worked with the constraints that I had little to no control over while embracing the advantages that the remote conditions presented that I was able to envision and design this remote, hands-on lab module. I encourage other faculty to similarly reconsider what can and cannot be done in our classrooms, and interrogate the assumptions underlying why we think they cannot be done. 

Check in with students regularly.

At the end of each iteration of the six-week lab module, we surveyed our students to identify the pain points they experienced in the lab, and used those responses to improve the lab for the next round. For example, it was through soliciting feedback from students that I realized it was hard for some students to dedicate kitchen or bathroom space in their homes for a six-week project. As such, we started making adjustments with each new iteration of the lab to make the experience more and more accessible for students.