Great Ideas in education
I recently watched a Ted Talk given by Derek Muller, creator of one of my favorite YouTube channels, Veritasium. (If you've never heard of Veritasium, go check it out right now. You will not regret it!) In this presentation, Muller described his research on how to make a video that effectively teaches physics. He gave the students a pretest on a physics concept, showed them a video that explained the concept, and then retested the students after the video. What he found was that, contrary to conventional wisdom, videos that presented physics concepts in a clear, easily understood way did not improve student learning. In fact, watching videos that presented concepts in a clear, concise manner resulted students who were more confident but just as lacking in their understanding. As he put it, “A clear, expository summary is worse than no instruction at all.”
Muller found that when he instead presented each concept as a question and gradually revealed the answer through the process of a dialogue or in the context of an investigation, students said the videos were confusing… and their test scores doubled. When asked how much mental effort they exerted while watching the expository film and the dialogue film, students indicated that they exerted significantly more mental effort in watching the latter of the two films.
I interpret these results as evidence that cognitive dissonance is necessary for constructing knowledge. Students need to wrestle with a physics concept before they really understand it. The best examples of this are when a student is presented with a phenomenon that contradicts the student’s “gut feeling” or intuition: the lead weight falls just as quickly as the aluminum weight; the balloon inside the car leans forward, not backward when you accelerate; the spinning bicycle wheel stays upright even when hanging from a string attached to one side, etc. These kinds of puzzling cognitive experiences are what drive discovery in physics for doctorates and high school students alike. When faced with the bizarre reality of the natural world, human beings are forced to either justify it or look at it in a different way.
One challenge in presenting students with these kinds of dissonant cognitive experiences is that students can sometimes justify the phenomenon using a faulty conceptualization rather than reconstructing their knowledge. They reimagine the data to agree with their theory rather than reimagining their theory to agree with the data. One way to guide students along the path of sound scientific reasoning is to make use of what Harvard Physics Professor, Eric Mazur, calls “Peer Instruction.” Using this method, teachers give students the opportunity to explain their conceptualizations to one another and discuss their ideas, much in the same way that scientists discuss ideas with each other. More often than not, students end up at a sound, logical conclusion when they have the chance to bounce their ideas off of each other and engage in scientific discourse. Dialogue is crucial to constructing scientific knowledge.
Another challenge with teaching a physics class the way that Muller teaches through his YouTube channel is that cognitive dissonance takes time. It is a much slower approach to learning physics. That said, it is much more effective than simply throwing ideas at students from the front of the room and expecting the ideas to stick in students’ minds like cooked spaghetti to a wall. I think it might be worth it to have students learn physics at a slower pace in order for them to develop a deeper, more solid understanding. I want my kids to be enthralled with the beauty and wonder of the natural world – I want them to love physics for the inquisitive, existential journey that it is rather than memorize equations for a final exam. I don’t necessarily want to produce physicists; I want to produce people who can think like physicists.