Keeping it Real: Using Unconventional Real-World Examples to Explain Concepts
Keith Hohn, PhD
Professor, Chemical Engineering - Kansas State University Engineering educators are dedicated to providing their students with rigorous training in engineering fundamentals that will enable them to become capable practitioners. To do this, most engineering professors follow a similar script: first, introduce and derive the fundamental equations describing some physical phenomenon and, second, apply these equations to a specific practical situation. This approach, a deductive approach to teaching, is logical and organized and effective for many engineering students. However, it has the disadvantage of being disconnected from physical examples; abstract theory is described before students are presented with concrete examples. An alternative is to use an inductive approach where examples are first presented, and then fundamental theories and equations are described. Prince and Felder (2006) reviewed the literature on the effectiveness of various inductive teaching methods, and concluded that, “Induction is supported by widely accepted educational theories such as cognitive and social constructivism, by brain research, and by empirical studies of teaching and learning” (p. 123). In the past few years, I’ve been using the inductive approach to teach chemical reaction engineering concepts in an upper-level course, with a twist. Rather than using technical examples to introduce a new topic, I use examples from everyday life that are familiar to students, but appear to have little relationship to chemical reaction engineering. I’d like to share two examples of these before talking about why I think this is an effective way to teach technical topics. A first example I have used is a game of musical chairs, where people walk around a set of empty chairs until the music stops, at which time they all try to sit down. The complication, of course, is that there are fewer chairs than there are people so someone will be left without a chair. I use this example to introduce a number of concepts related to reactions on solid surfaces, where instead of people competing for empty chairs, we have molecules competing for empty sites. For example, we discuss how the competition for surface sites means that not all molecules can be adsorbed on a catalyst surface (just like all people don’t get a chair when the music stops), which impacts the ultimate reaction rate on that surface. A second example I have used is the rubber duck races that are often used to raise money for charity. In such an event, hundreds of rubber ducks are poured into a flowing waterway. These ducks are dispersed into the flowing water, and quickly assume some shape depending on the flow pattern in the waterway. I use this example to introduce the concept of residence time distribution in chemical reactors: the idea that molecules spend different amounts of time inside reactors and the distribution of those times is related to mixing in the reactor. I use the rubber duck example to describe how flow patterns in reactors lead to different residence time distributions and how the residence time distribution can be measured experimentally. For both of these examples, I show a video, ask the students to describe what they saw in the video, and then open a discussion on how the video relates to the chemical reaction engineering concepts. This has three substantial benefits for student learning. First, enhances learning for students who favor an inductive approach. Second, the videos act to draw student attention. Videos of people playing musical chairs or floating rubber ducks are not the norm in upper-level engineering course, so when my students see these videos, they are immediately engaged and interested in the resulting discussion. I believe that students are better able to understand the mathematical details of the physical phenomenon after I have grabbed their attention with the unconventional example. Finally, the unconventional, but real-world example provides a hook to student’s prior knowledge that helps students build new knowledge (Zull, 2002, 2011). I am sure that there are examples like these that could be used to explain technical or theoretical concepts in other disciplines. I encourage you to consider whether unconventional examples – from games, movies, literature, pop news – could be used in your class to grab students’ attention and enhance their learning. References Prince, M.J, & Felder, R.M. (2006). Inductive teaching and learning methods: Definitions, comparisons, and research bases. Journal of Engineering Education, 95, 123-138. Zull, J. E. (2002). The art of changing the brain: Enriching the practice of teaching by exploring the biology of learning. Sterling, VA: Stylus Publications. Zull, J. E. (2011). From brain to mind. Sterling, VA: Stylus Publishing This blog entry is derived from material originally presented at the 2014 SPOTLIGHT K-State event, held the evening of March 31, 2014.