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Interactive Teaching Techniques: An Interview with Professor Eric Mazur

ANDREA RIVERA, Harvard College '22

THURJ Volume 13 | Issue 2


Datkanski Professor of Physics and Applied Physics and Area Chair of Applied Physics at Harvard University, Member of the Faculty of Education at the Harvard Graduate School of Education, and Past President of the Optical Society, Professor Eric Mazur is a leader in the fields of ultrafast optics, condensed matter physics, and peer instruction. He is widely known for his research and work on Peer Instruction, an interactive teaching method aimed at engaging students in the classroom and beyond. He has been awarded the Presidential Young Investigator Award by President Ronald Regan, the Esther Hoffman Beller Medal by the Optical Society of America, and selected as one of 75 most outstanding American physicists by the American Association of Physics Teachers. THUR] writer Andrea Rivera had the chance to talk to Professor Eric Mazur about Peer Instruction and how it has changed during distance learning as well as his current research.


AR: Thank you so much for agreeing to speak with me. Could you please tell us about your education and your career so far as well as how you got involved with both physics and education?
EM: It has been such a long trajectory. Growing up in the Netherlands, my mother was an art historian and my father was a theoretical physicist so I was constantly torn between the arts and the sciences. However, I developed a passion for astronomy very early on in my life. That means that when I went to Leiden University, I chose astronomy as my major, but that didn't last very long because it was taught so poorly that I lost track of the bigger picture. Everything was about plugging numbers into equations and making calculations, but the bigger picture was gone. After that, I switched to physics only to discover that it was no different from what I had experienced in Astronomy. I was very disillusioned for a long time, until I joined a research group. That's when I rediscovered the beauty of doing science. Now, rather than replicating what people had done before, I was discovering how nature works and if it hadn't been for that, I would have probably dropped out and my life would have been very different. I went on to complete my Ph.D. at the same institution and the same research group I worked with during undergrad. After graduating, I really wanted to work in industry because my parents were academics and I desperately wanted to do something different. My father, however, encouraged me to postpone my job offer at Phillips to go study in the US for a couple of years and learn more about lasers and optics. I got an offer from Harvard and here I still am, believe it or not. I was only supposed to stay at Harvard for two years, but they offered me an assistant professor position. Six years later, I got tenure and instead of going into industry, I ended up in academia.

AR: We know that you are an avid advocate for peer instruction and interactive teaching. How do you think this approach to teaching is different and how do you implement it in your teaching style?
EM: When I started teaching, I naively thought that because I learned physics by listening to lectures, that my students were going to learn physics by listening to me and I never questioned the underlying assumption that's there. For me, it was so obvious that that’s how you teach. To make matters worse, I started getting very high evaluations so I thought I was doing a great job. it wasn't until 1990 that I read an article in the American Journal of Physics that claimed that students learn next to nothing in an introductory physics course that I began to question my teaching style. The research consisted of a short test given to a large number of non-physics majors and physics majors at the beginning of a semester-long introductory physics course as well as at the end, and then they later compared the scores and the results showed that there's hardly any difference between the initial and final scores. They also showed that the scores did not correlate with teaching evaluations.
When I read that article I was very skeptical about it because I thought there was no way that this would apply to my class. I was determined to show that in my class, my students would ace the post-test. That was a transformative moment in my career because the results were in fact no different from the research findings. That led to quite a bit of
soul searching and it helped me discover that the students became very good at solving the computational problems at the end of the course, but when they were word-based questions they would flunk completely because they had no underlying conception of the topics. As I was discussing the test with my students, I could tell by their confused faces that they didn't understand my explanation. So I said to them, why don't you just discuss the questions with each other? Something happened that I had never seen in my lecture- based classrooms: they convinced each other of the right answer in less than two minutes. It made no sense to me. I, the expert, spent more than 10 minutes explaining it without any effect and the students just talked to each other for two minutes and got it. Later, I realized that it's because I learned the subject a long time ago. For me, it's so obvious that I can no longer imagine what the difficulties are in learning the material. And that's what gave rise to peer instruction. The students are more likely to convince their peers than the professor who is in front of the class because they understand better what's going on in their brain. Although I never intended to create a new instructional technique, it took off from there.
AR: That's really interesting. Given the pandemic, what was the biggest barrier bringing this approach virtually?
EM: The peer instruction that we do now in the classroom is completely asynchronous. | found that by trying this approach synchronously many students would not have enough time to fully think about the problems in the allotted time while others would fly through the questions. That's why we divided the students into I believe in learning, by doing whether it's for instruction or anything else. I think that's the key point in the virtual approach.
AR: That’s a great approach! In your introductory physics course this year, your students present their class projects to high school students all over the world. What inspired this idea?
EM: Before the pandemic, we had the class project fairs in a public space on campus. I would ask colleagues to come from Harvard and MIT to be the judges. When we went online, I found it very difficult to recruit colleagues because everybody was so preoccupied with keeping their own courses running. In retrospect, I'm laughing about this because even though we were on zoom I was still looking for local judges when it doesn't matter where you are as long as it's an accessible time zone. People can be
anywhere so I started to invite colleagues from universities in Europe, Brazil, and so on. However, over the summer, thought that we should really open this up to a much broader public. I'm actually the Pl on a grant for the National Science Foundation, which essentially attempts to improve high school physics education as well as high school
science education in general. Through this project, we have found that many teachers are struggling to find ways to keep their high school students busy and learning the material in creative ways, not just in the US but all over the world. And that's when I thought, let's see if we can give back some of the things we do in the classroom to high school students. it also gives my students a sense of a higher purpose. Adding a component of empathy or social goods makes it so much more engaging for the learner.

AR: I completely agree. As a student in the course, | am really glad that we get to share what we learn with younger students. I am curious as to how you think instruction will change after being a whole year online? And if you think that there are any lessons that we can learn?
EM: I love this question. it is a really great question. In fact, it's keeping me awake at night right now because we just received the news that Harvard is planning to bring everybody back to campus in August and I feel a sense of both relief and worry. I'm connected to my students in a way that I have never been connected to. Teaching is not just about delivering knowledge, it’s so much more. There's a human connection to it. Strangely enough, the way I teach now is so much stronger. The data that I've collected in my classes shows that our approach now is significantly better than it was a year ago when we were on campus. The learning is better, the feeling of being part of a community is higher, and the sense of growth and autonomy is larger. So I think that in a sense, I have seen the way to a better future. One of the things I've discovered with online platforms is that every student is sitting in the front row. The engagement can be so much better if you do it in a smart way. Now, I'm not, advocating that we do everything online from now on. However, we really need to sit down and evaluate what has worked and what has it because it hasn't all been bad. For some activities, I actually am starting to believe that the pandemic has shown us a way to the future that would otherwise have taken maybe another hundred years or so.
AR: I agree. Although we're all eager to go back to. in- person instruction, we definitely need to reflect on what has worked during the past year. However, I wanted to quickly talk about your work before we finish. Could you briefly describe your research?

EM: There are three parts of my research group. One part focuses on education research and ways to improve education using data we've collected in AP50 and other courses. The other two parts are in biophotonics and nanophotonics.
Nanophotonics is the field that deals with the manipulation of photons particles of light at the nanoscale. Most of our modern technology including smartphones, computers, etc. all manipulate electrons at the nanoscale. However, electrons are very power-hungry’ and most of the energy they use is wasted on heat rather than actual computation. This means that if we are able to replace computation with electrons, by computation with photons we would solve an energy problem. The problem is that we don't have a very good ability to manipulate light at the nanoscale, at least not in a way that's easily scalable. Part of my group works on developing materials that permit the manipulation of light at the nanoscale. Although we are still far from application, technology moves fast and we are very happy with what we have been able to do so far.
The biophotonics part of my research group uses light to manipulate living matter. We started by conducting research on the viscoelastic properties of fibers in collaboration with a professor from Harvard Medical School. In essence, we created a technique to do subcellular surgery by developing a scalpel that permits you to go inside the cell and make a cut without killing the cell or damaging the cell membrane. Light is actually perfect for that because you can focus it very tightly so that the cell membrane is not in the focused part of the beam, but rather whatever organelle you want to hit inside the cell. This was just the beginning, right now we are focusing on using light to deliver cargo to cells. For example, there are many techniques to deliver cargo to cells, either a fluorescent marker or CRISPR-Cas9, and the way that these techniques typically do so is through electroporation, which ends up killing a lot of cells. This is why we developed a technique that is completely optical and that permits you to actually tolerate and deliver cargo to a very large number of cells in parallel. In fact, we keep discovering new ways and substrates to facilitate this technique. It’s incredibly exciting because even though we know the technique works and we can make it work, the exact mechanism is still unclear, which is of course both frustrating and exciting. It's frustrating because we'd like to understand exactly how it works but it's exciting because it means there's something to be discovered here.
AR: That sounds amazing! I hope that readers who are interested in these fields can learn something new through this important research being conducted by the Mazur group. To conclude, what advice do you have for aspiring scientists and researchers?
EM: All human beings are born scientists. We're all innately wired to want to understand the world around us from a very young age. We all have an innate desire to want to know why. And science is all about asking why. That's why I think to be a successful scientist it’s important to never give up on the inner child in you. My advice would be to never lose that innate curiosity. Nothing is more fulfilling than discovering how something works, regardless of whether or not somebody else has already thought of it.
AR: That is an amazing way to view science and some of the best advice I've heard for aspiring researchers as well! Thank you so much for taking the time to talk to me and answer my questions.
EM: You're welcome, Andrea. I really appreciate your questions. Thank you!

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