“I believe that I learned more about the machine and how… [it] actually works in more detail from that one activity… than I would ever have done had I just read somewhere about how a coffee maker works in some book.”
Have you ever considered what coffee is and how to brew the perfect cup? We invited over 1200 incoming engineering students to do just that in their first week of classes, in a “pilot” activity launching the Engineering Ideas Clinic. Intended to facilitate learning by exploration, students were first asked as a class to identify the safety hazards associated with using and then dismantling a coffee maker. This proved to be both effective—identifying many hazards that we instructors had missed—as well as “a fun and exciting way… to be introduced to WHMIS”.
Groups of students were then given either an electric drip machine or a Moka pot and asked to brew a “small amount” of coffee (usually interpreted as a full pot). Further instructions were not provided and, since a surprisingly small number of students are coffee drinkers when they arrive on campus, this caused some challenges. Where does the water go in the Moka pot? Which coffee goes in which machine? During brewing, groups were asked to consider the physical processes occurring in the machine and make a list of all the components they expected to find inside. This resulted in a number of points of contention, such as whether a drip machine must include a pump.
If this is coffee bring me tea; and if it is tea, bring coffee.* Perhaps fortuitously, the laboratory venue precluded any tasting of the resulting brews, but the groups moved on to consider what “coffee” is and its desirable characteristics, such as bitterness, acidity and colour. Characterizing coffee can be achieved as a combination of sensory perception—sight, smell and taste—and analytical measurement—we provided thermometers, pH probes and spectrophotometers.
With the coffee brewed and characterized, it was time to discover whether the guesses at the machine’s internal components were correct. While the classes differed in their zeal for disassembly (most of the machines could be re-assembled), some surprises were in store inside, such as the amount of empty space, the absence of a pump, the mystery object in one of the tubes (a one-way valve) and the single heating element serving double-duty as water and hot-plate heater. While the Moka pot was much easier to dismantle, figuring out its operation was usually more challenging. Groups prepared a sketch of the machine they had and used this to explain its operation to a group with the other machine.
Finally, the instructor brought the class back together for a rich discussion, ranging across how the machines work, measurement variability and error, communication with technical drawings, constraints and criteria for design, the concept of design specifications and answering questions such as “what is coffee?” and “how is the filter basket made?”. Led by their own inquiry and exploration, this activity provided students with an opportunity to consider what engineering design is and how it is underpinned by principles of physical science. In keeping with the spirit of the activity, I will leave the last words to the students:
“Learning how a common household object required various engineering concepts to design and construct really opened our eyes to how applicable our engineering education can be.”
“The lab was a great hands-on experience. It was very interesting to see the inner workings of coffee makers and the engineering design behind them. Hopefully we can have more labs like this one”
“The ChE 102 Coffee Lab was one of the best moments of 1A so far. I liked that we students finally got to experience a hands-on introduction to the world of engineering. Taking apart an everyday object and analyzing how different parts help the machine function as a whole was a fun way to apply engineering concepts that we’ve started learning about in class. I hope they do more of these hands-on labs since they’re a nice break from just lectures and theory.”
With thanks to Patricia Duong, Partho Mondal, Gerry Shebib, Inzamam Tahir and Geethan Viswathasan from the Engineering class of 2019 for allowing me to quote their comments on the coffee activity.
*This quote is sometimes attributed to Abraham Lincoln, though it appears to have been an old joke even in the mid-nineteenth century.
