Students don’t always understand what you think that they understand

Below is a figure that had a tremendous impact on me when I saw it ten years ago in a paper written by Carl Wieman and Kathy Perkins (figure adapted from work done by Eric Mazur at Harvard). The figure shows two  problems designed to test the same basic physics concept, namely how current flows in circuits. Determining the current through the various resistors in part (a) requires solving a pair of equations, and as a teacher a reasonable assumption is that if students can do the question correctly then they understand the concepts. However, what Mazur found is that many students could solve this challenging problem but were unable to solve the (apparently) much simpler conceptual problem in part (b) asking about how the brightness of the light bulbs will change when the switch S is closed.

The students were simply using a “recipe” to solve the problem given in (a), indicating that they would quickly become confused when attempting to apply their knowledge outside of the artificial realm of the problems that they had practiced. This realization played a significant role in my decision to spend three months as a Christine Mirzayan Fellow at the National Academics with the Board on Science Education , where I became convinced that active learning approaches could help students with these conceptually challenging topics.


My New Year’s Resolution

For the last few years I have  joked that my New Year’s Resolution was to start using Facebook. I have had an account for many years, but I only log on once a year, and I have to confess that I find the whole thing rather mystifying. As a professor at MIT this is all a bit embarrassing, so this year my resolution was to at least update my personal website, which hasn’t changed for ten years. This blog is the result.

Part of my motivation has also been the excellent blog by my friend Arjun Raj. We were postdocs together in the van Oudenaarden lab, and his blog has been a fun way for me to keep in touch with him (or at least to hear what he has been thinking about, since I typically don’t respond in any way).