Teaching

“The value of an education… is not the learning of many facts, but the training of the mind to think something that cannot be learned from textbooks.” – Einstein

I’ve had the chance to teach a variety of undergraduate physics courses as a teaching assistant (TA) and as supervisor. I love teaching and have learned a great deal from interacting with students and professors, as well as from reading articles on science education research. Below you will find the courses I have taught for, some of my views on teaching, and a bunch of fun exercise problems. More educational resources can be found on the Links page.

Courses taught

  • 2018
    • Supervisor for Part IB Physics A: 2nd year Natural Sciences, Cambridge, 2018-19
      Experimental methods, Waves, Quantum physics & Condensed matter physics
      Held weekly supervisions for a small group of students
  • 2016
  • 2015
    • TA for PHYS 2213: Electromagnetism (engg majors), Cornell, Fall 2015
      Instructed discussion and lab sections, managed Q&A forum on Piazza, designed new demonstrations (with Jenny Wurster), graded
      Student evaluations: find here
      Course instructor: Kyle Shen
    • TA for PHYS 1203: Physics of Heaven and Earth (non-science majors), Cornell, Spring 2015
      Instructed discussion section, graded
      Student evaluations: find here
      Course instructor: David Kronreich
  • 2014
    • TA for PHYS 2208: Fundamentals of Physics II (pre-meds), Cornell, Spring 2014
      Instructed three discussion sections, prepared quiz problems, graded
      Student evaluations: find here
      Course instructor: Matthias Liepe
  • 2013
    • TA for PHYS 2208: Fundamentals of Physics II (premeds), Cornell, Spring 2013
      Instructed discussion sections, prepared quizzes, graded
      Student evaluations: find here
      Course instructor: Matthias Liepe
  • 2012
    • TA for PHYS 2207: Fundamentals of Physics I (premeds), Cornell, Fall 2012
      Instructed discussion and lab sections, prepared quizzes, graded
      Student evaluations: find here
      Course instructor: Kathy Selby

Views on teaching (physics)

I enjoy teaching – its a challenging and rewarding exercise. My ideas about teaching keep evolving, but here are some of the things I have learned thus far and try to follow:

  • To be a good teacher, one needs to be enthusiastic about the subject oneself and be able to share some of that excitement with the students (think Feynman!), in a way which makes them think and ask questions. Recent studies have shown this has a measurable impact.
  • It takes time! Learning how to teach is a process of trial and error and requires a lot of effort. Similarly, students need time to absorb what they are being taught. Too often teachers and students are in a hurry to “get things done” which compromises learning.
  • Catering to students from different backgrounds in a large class is challenging. Still, one should strive to empathize with the students and use evidence-based approaches (such as active learning) to better accommodate all students.
  • Most of us learn physics (or science in general) by seeing, thinking, and doing. Therefore one should try to promote these activities, e.g., by designing puzzles and conceptual exercises, engaging with demonstrations, holding open discussion forums etc.
  • Students often come with preconceived ideas, or there is a disconnect between what they believe and what they know “should” be the answer (think Newton’s 3rd law!). Thus it can be useful to discuss why something doesn’t work, rather than simply giving the right answer.
  • Teaching should be a dialogue between the teacher and the students. Thus the teacher should have an open mind and be willing to learn from the students. I often learn new ways of thinking about a problem from interacting with students.
  • Its good to keep reinventing. Whenever I teach, I like to come up with new exercises which illustrate a concept (you’ll find some examples below). Not only is the process enjoyable, but you invariably learn something new about the subject yourself.
  • Student feedbacks are useful – not only at the end of a course, but on a regular basis throughout the course – for better learning and improving as a teacher.
  • Teaching outcomes can be measured and should be studied scientifically. Indeed, physics education research has developed into a field of its own and is shedding light on what works and what doesn’t. One should try to incorporate these findings as much as possible.

Resources

Below is a collection of exercise problems, animations, and notes I prepared – those which I had reason to write up and save for posterity! More resources can be found on the Links page.

Exercise problems

These were largely motivated by my interactions with students who asked some very intriguing questions! They are also influenced by the books that I read.

  • Concepts-based problems on Special Relativity: These were designed to be clicker questions in an introductory course on special relativity (see above). Their goal is to illustrate that not everything is relative and that the bizarre predictions of the theory, such as time dilation, length contraction, and relativity of simultaneity, are all necessary for logical consistency. The problems were greatly inspired by two excellent thought-provoking books by David MerminSpace and Time in Special Relativity and Its About Time, two of the best expositions I have read on the logical coherence of Special Relativity.
  • Numerical problems on Electromagnetism: These were used as homework problems in an advanced E&M course for undergraduate physics majors (see above). They are more focused on gaining insight into electromagnetism than on numerics. Although they were designed for beginners in Mathematica, other programming languages should work fine.
  • Exercise Notebooks (6.6 MB): These Mathematica (version 11) notebooks were used as exercise problems in the above E&M course, both for learning Mathematica and using it to investigate problems which cannot be solved analytically.
  • Mechanics problems: Quizzes given to freshman physics majors (see above).
  • Quiz problems on Electromagnetism: These were used in a course for pre-meds (see above).
Fun animations
  • We are taught in electrostatics that all free charges reside on the surface on a conductor. But (how) do they always reach such a configuration? Turns out there are two crucial factors – dimensionality and energy dissipation: [pptx (4.5 MB)] [key (5 MB)].

    In particular, they can self-organize into beautiful patterns!

  • Imagine a charged pendulum in a vertical magnetic field. Depending on the field strength and how you release the pendulum, it can undergo different types of oscillations, forming beautiful trajectories: zip file (can be played in Mathematica or the free CDF Player).
  • As seen from Earth, Mars and other planets move backwards every once in a while. This retrograde motion puzzled astronomers since the time of Copernicus. See how it emerges in this interactive simulation: zip file (playable in Mathematica or the free CDF Player).
Notes
  • I try to paraphrase Einstein’s first “derivation” of E = mc2 in a simple language: pdf.
  • Frequently asked questions in an introductory course on electromagnetism: pdf.