Bridges to Learning Sometimes Fall Down

One of the biggest challenges I face as a University Lecturer is keeping large student groups engaged for extended periods of time. This semester I am lecturing to groups of up to 500 students for as much as two hours in a row. Moreover, these students often have back-to-back lectures, meaning that they might be in a lecture room for four or five hours at a stretch. How can anyone stay focused and engaged for that period of time?

In this week’s FULT module, we learned about strategies, activities, and resources for keeping students engaged in the lecture hall. I was particularly interested in a video describing the seminar-style lectures of Giuseppe Carabetta, a Senior Lecturer in the Business School at the University of Sydney.

Carabetta demonstrates great skill in managing the give-and-take of a seminar in a traditional classroom setting. Although he makes it look easy — interacting with students, posing discussion questions, going with the natural flow of the lecture — it actually requires considerable mastery to steer a lecture like this towards your learning goals.

While it is natural, as a first-time lecturer, to focus on content rather than process, Carabetta notes that “effective process feeds content”. What this means in practice is that interactive activities and video clips are a great way of guiding your students through complex content in an engaging way. And even though there is always a risk when trying something new, a lecturer can prepare back-up activities in the event that things don’t work out as plans.

So how can I bring this kind of activity-driven “guided exploration” to my own lectures?

I would like to bring more interactive activities into the lecture hall: live demonstrations (with online polls to see what student think will happen); videos (with think/pair/share discussions); pop quizzes (with instant feedback via online tools like poll2go.com); and question-and-answer sessions. These kinds of activities also vary the rythme of the lecture, so that students get a bit of a breather from time-to-time.

As an exercise, I designed a more interactive teaching strategy for teaching engineering students the concept of resonance in mechanically forced systems, using the Toohey (1999) model as a guide to structure my lecture:

Introduce the topic: Ease students into the concept with a 5 minute notes-free discussion of the effect of resonance in mechanically forced students, and then open up the lecture to questions from the students.

Get to know it: Next, work through a mathematical example to see the phenomenon of resonance from both the engineering/physical perspective and the mathematical perspective.

Try it out: The students are then given a pop quiz with an example mechanical system and asked to identify the natural frequency and predict what will happen when the system is forced resonantly. The students are asked to first work independently, then to pair up and compare answers and help each other (think/pair/share).

Get feedback: The students can then submit their answers online and get live feedback to see how they did.

Reflect and adjust: Have the students think about where they might have gone wrong in their calculations, and point out easy pitfalls.

Use it: Finally, finish the lecture with a real-world example that exhibits the features we have seen in class, for example: Nicholai Tesla’s “Earthquake machine” or an opera singer breaking a wineglass by singing at the resonant frequency.

Interestingly, the same week we were covering Teaching Strategies in FULT, I was lecturing on this topic and opened up the discussion to the class. In my interaction with students, I was surprised to discover that an overwhelming majority of students had been taught this material in some form or another in the past and they had all been given exactly the same misleading anecdote of resonance in the real world. One student asked if I would be showing a famous video of the Tacoma Narrows Bridge, which collapsed in strong winds in 1940. Curious, I asked how many students had already seen this video. Nearly every hand in the room went up. Here is the video:

What was astonishing about this is that the Tacoma Narrows bridge collapse is not an example of resonance. As the Wikipedia entry for the disaster explains,

The bridge’s collapse had a lasting effect on science and engineering. In many physics textbooks, the event is presented as an example of elementary forced resonance, with the wind providing an external periodic frequency that matched the bridge’s natural structural frequency, though the actual cause of failure was aeroelastic flutter.

The lesson I learned from this is that students are not blank slates, but come into the classroom with preconceived ideas, some of which are inaccurate or simply wrong. This well-known phenomenon is captured by this marvelous video of Harvard graduates explaining the origin of the seasons (apologies for the quality):

These students (some of whom are physics majors!) incorrectly attribute the seasons to changes in the distance of the Earth from the Sun as it orbits. In fact, the seasons are caused by the Earth’s tilt : Earth’s orbit is almost circular and has little or no effect on the seasons. I wonder how these students would explain why it is winter in Australia when it is summer in the US, and vice versa!

What is remarkable about this example is that it can be traced back to a single figure, printed in almost every high school level science textbook, showing a picture of the Earth-Sun system at an angle that dramatically exaggerates the ellipticity of Earth’s orbit.

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Students carry these kinds of misconceptions into the classroom with them all the time. When we teach content, we are not simply filling an empty vessel. This is, for me, why the idea of teaching “effective process” is so appealing as a teaching strategy. I would much rather teach students how to think for themselves, and stop trying to fit an elliptical peg in a circular hole.

References:

Toohey, Susan. Designing courses for higher education. Open University Press, 325 Chestnut Street, Philadelphia, PA 19106, 1999.

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