# Spring 2012: Electromagnetism (PHYS2217)

This was a course for freshman physics students (as well as a few engineers who were interested) at Cornell University. The majority of the students in this course were freshman, although a few sophomores also joined in. I was a TA for this course, which involved running a weekly section, as well as grading. I served as a substitute lecturer for a week early on in the semester when the professor was away, and I also asked to lecture the special relativity component of the course, which occurred in the last week of the course.

Download Worksheet## Recitation Sections

This semester was interesting, because I was taking a course in teaching and learning in higher education, and attempting to incorporate what I learned in that course into my teaching. For the most part, I gave an overview of the concepts and equations that I wanted to look at, and then had the students work in groups, often at the blackboard. I made a worksheet one week for groups to work on together. The idea was for groups to work through some aspects of electromagnetic waves. Unfortunately, when I said "Get into groups and go!", the students all sat in their seats like it was an exam and were deadly quiet as they worked through the questions. Next time, I'll start by making groups!

## Guest Lecturer

I gave three lectures on Gauss' Law and the electrostatic potential to the students. The content and pace was essentially set from notes from previous years, and so it was not too intensive to prepare. I toyed with various teaching methods, including getting students to perform calculations in the lecture, which received positive feedback. Overall, anonymous student responses were very positive from these lectures.

## Special Relativity Lectures

I thought you were a good lecturer, and showed an obvious love of the subject.

I learned more in the last week with Jolyon than I did the entire rest of the semester (no exaggeration), especially with regard to the fundamental structure of the theory.

I attempted to teach special relativity as it applies to electromagnetism in three lectures. I was under the impression that the students were mostly in their fourth semester of undergraduate, had seen vector calculus, differential equations, and linear algebra; alas, most were freshmen, and had not seen linear algebra yet, which made life a little hard. I was informed that the students should have seen special relativity before, in their mechanics course, and so in the lectures, I focussed on introducing index notation, and casting the formalism of special relativity into that language. However, even without introducing special relativity, it was still slow going, and I felt like I was pushing forward about twice as fast as I should have been (mostly to the detriment of examples). Regardless, we covered all of the important material, and most people seemed to get it, so I was quite pleased. After the final lecture (on the last day of semester), four students asked if I had time to give them a lecture on general relativity. An hour and a half later (and the basics of general relativity), they were asking about subject recommendations for pursuing a physics major.

Download Notes Download Solutions[The notes] are thorough, well-written, and I will hold on to them throughout my education. I loved them. SO great! Jolyon should write textbooks! Although I needed the lectures and the notes to fully understand the notes, he answered all my questions as they popped up and gave nice exercises throughout the notes.

I wrote a 23 page handout to go with my lectures, which went through all of the calculations I brushed over in lecture. The handout was intended to be a first glance at this aspect of physics, and I was very clear about which aspects of the notes I considered to be important for them to understand, and which parts I just wanted to give them a first exposure to, but not necessarily completely understand. Students seemed to appreciate the comprehensiveness of the notes. A page of simple problems was at the end, and I also wrote up full solutions for the students.

In the recitation section for special relativity, the first half of the tutorial was spent fielding questions on notation, while the second half was spent discussing the infamous barn paradox. We cast the barn paradox into the notation that I had introduced, and did calculations there. At the end of the section, most of the students agreed that they now understood it, whereas it had confused them when they were exposed to it for the first time. Although I didn't have a chance to assess their understanding of the material, I got the impression that the students got a lot out of that section.

I did [go to office hours]. They were very, very helpful. I think you really did well with the small group and getting us all involved. Your enthusiasm was inspiring and engaging. They were by far the most productive office hours I've ever been too, and I think anyone who didn't go really missed out on a great introduction to special relativity / index notation.

To help students understand the material, I held special office hours one day, from 3:30 to 5:00 pm, which six students attended. The first hour or so was mundane, covering material from lectures in more detail. However, then the students started asking me to give them sneak peaks for the final lecture. We continued, getting more and more enthusiastic and interested in the material, until we discovered we were an hour overtime, and I had to leave for a meeting. This was a particularly exhilirating experience, and one I hope to replicate a number of times throughout my career.

Download Beatles NotesI began the lectures with a motivating question, based on the Beatles measuring charges in different reference frames. The final lecture finished with the resolution of the apparent paradox that the motivating question contained. Students asked me to write up the discussion, which I've included here.

## Reflections

I think I did a reasonably good job of teaching the sections, as well as the guest lectures. With regards to the special relativity component, I'm glad I had the opportunity to plan, prepare, and present an entire module. I found that I had no intuition for how much material I could cover in a lecture, and that I also need to work on my use of the blackboard (write smaller!). If I had the opportunity to teach special relativity again, I'd probably try to cut back on some of the material, and insert a number more examples instead. In particular, I thought the students had a background in linear algebra, which most apparently didn't. This assumption meant that I needed to go slower in a number of places and use examples to elucidate what I was doing, rather moving on. It would be much better to give this section of the course five lectures instead of three. Regardless, I'm proud of the notes that I wrote for the students, and I would certainly use those again. At the end of the day, I know that I managed to excite at least half a dozen students on the subject matter, and expanded the horizons of the best students, hopefully without leaving the poorer students behind.

## Evaluations

I did enjoy the last three lectures that you gave. The whole course would have been less interesting without them. Your lecture notes helped me to appreciate the material better. I like them.

The standard evaluations for this course are available here. As far as student evaluations are concerned, I think this is glowing.

I also ran a special survey for my special relativity lectures, in order to get some specialized feedback. The results are available here. Most students found the lectures clear, the material interesting, and the presentation followable. As I identified in my own reflections, I should have gone a little slower for the students, although I was a little surprised that a few students thought I was going too slow! A number of students would have liked more examples, which I also identified in my reflections. The lecture notes I wrote received glowing reviews. Students particularly liked when I asked them to take a few minutes to do a calculation, or think about a problem, before I went over it in class. The vast majority of students claimed that they learnt something, ranging from just the concepts I stressed through to "everything". Most people rated my lecturing as "excellent".