March 19, 2017

Slides and supplementary material from my CS-AAPT presentation

I presented the lab we recently did in class at the Chicago Section AAPT Spring meeting.  The lab was another one of my "single-sentence labs" which basically came down to:

"Measure the capacitance of a aluminum foil parallel plate capacitor as you vary the separation of the plates by using your textbook."

That may be more detailed than what I actually wrote on the board in class, or it might be less detailed.  I don't really remember.

All we did in this lab was make a capacitor by putting sheets of foil inside the physics textbook and measure the capacitance with multimeters that we had in the storeroom. The meters had the ability to measure capacitance. We were measuring capacitance in the nano-Farad range.

I thought the lab was a great learning opportunity for the students and for me, so I wanted to share that with other physics teachers.  I got a request for the materials and lab instructions that I used for the lab.  Since I do "single-sentence labs" there really isn't a set of lab instructions to share, but I put together my notes from what we did after the first time through the lab.

Here are the slides for my presentation with some extra notes added.

Here are the notes I used in class for discussing aspects of uncertainties in measurement.

Thanks to @DrDawes for the suggestion of the lab!  I'd love feedback from anyone who does this lab (or similar) since I plan to do this again in future semesters.

March 08, 2017

Traditional physics teaching is not always a virtue, but neither is being an arrogant physicist

(This turned out to be a lot longer than I expected it to be. The tl;dr version is that I agree that creativity in physics classrooms is important, but I disagree with much of the narrative of the Physics Today commentary by Ricardo Heras.)

In his Physics Today letter "Commentary: How to teach me physics: Tradition is not always a virtue" Ricardo Heras lays out all the ways in which he believes his first two years of undergraduate study have been a disappointment. He feels his professors focused too much on textbook problem solving, that he was overwhelmed with the workload which forced him to resort to memorize equations, and that the first two years had no room at all for creativity.

First, I'd like to say that it was pretty bold of Mr. Heras to characterize the entire University College of London department of physics and astronomy as a group of faculty which discourages students from engaging in deep learning and understanding of physics and to make that characterization in one of the most widely read magazines by physicists around the world. I wish him well in his last two years at UCL if he is intending to remain there. It's also a pretty bold claim to make that your creativity was stifled when in addition to the Physics Today letter, you had three manuscripts (1, 2, 3) published in the European Journal of Physics as well as one publication in a journal called New Astronomy. (I know nothing about the last journal.) I mean, every physicist has at one time in their life been accused of being arrogant, but you don't need to go out of your way to do so before finishing your undergraduate studies.

That is not to say that his experiences were not real or that his opinions do not matter. As an instructor of physics, I know full well the value of feedback that I can receive from students. I also know what feedback is meaningful and what to ignore. (Also, I know when students are hitting up the thesaurus to write a lab report. "Vicissitudes"? Really? Anyway....) But to address his points and taking them at face value, I would agree that:

1.) problem solving alone is not enough to learn physics and that
2.) we need to make more room in our curriculum for encouraging creativity

A surface reading of the commentary would yield little to disagree with.  Let's dig a bit deeper, though.

Mr. Heras quotes Feynman many times in this brief letter: five times he quotes Feynman by my count, he has two other quotes which are about Feynman and he has one quote from Noam Chomsky. Of the two main scholars he discusses (Feynman and Chomsky) both are sometimes put on pedestals, rightly or wrongly, as examples of the Lone Genius. This is not the first time that Mr. Heras has discussed his belief in the importance of physics as an individualistic pursuit. When that letter appeared in Physics Today, there was a bit of discussion online including this post at Scientific American and this response by Chad Orzel.  Both of the responses presented a more nuanced view of the history and present physics research environment; a nuance that comes, I will add, with the experience of being immersed in the physics community.

If he cares about physics education,  he should be engaging with the physics education community, which is generally not well represented in Physics Today.  Mr. Heras seems to care more about engaging with the physics community without bothering to learn about physics education reforms of the past ~40 years. On the one hand, he publishes in the European Journal of Physics (which has a mission similar to the American Journal of Physics), and he knows quite a bit about what he has published. I read the papers on the Lorentz Transformation that he authored, and there is little doubt that the physics contained within is solid. But, as evidenced by his reply to a critique of one his papers he does not show an awareness of the pedagogical content knowledge necessary to teach these topics to students seeing them for the first time. A real irony of all of his complaining about "traditional" physics instruction (with the rote problem solving methodology) is that the type of physics he is most interested in are the highly theoretical mathematical branches of physics, which lends itself naturally to solving some intense textbook problems.

For another example, see the special course he taught last summer on Classical Electrodynamics and Symmetry principles in Maxwell’s Equations. He claims that "Electrodynamics is a very exciting subject to learn. Unfortunately, Maxwell’s equations...are often taught in a rather dull manner, which usually involves solving a lot of mostly uninteresting problems without emphasizing the pivotal role symmetry principles play..."  The class is described as appropriate for advanced undergrads and beginning graduate students. The recommended textbooks include EM books by Griffiths, Jackson, and Schwinger, among others! And this is supposed to be a summer course? I find it hard to believe that this course can be successful in helping more

He points out that he learned more by pursuing a topic he was interested in than by calculating the electric field of a spherical charge. Yet he shows little awareness of WHY students are asked to pursue simple models such as spherical charge configurations. (It's baffling to me, for example that someone so enamored with special relativity would not see the usefulness of exploring the electric field of a charge configuration). In my classes I am constantly reminding students to ask themselves what they learn by doing the problems we choose.  Some of our best students are limited by what they are not even aware that they don't know - developing metacognitive skills is a critical part of a student's growth which does not show up in any physics syllabus, yet is important for reaching full potential as a physics major.

Mr. Heras is probably not a typical physics student. He spent some of his pre-college years teaching himself physics. I have no way of knowing how firm his conceptual understanding of basic physics concepts was before starting his university studies. But I have met several students through my teaching career who were honors students and had tried teaching themselves advanced physics before getting to college. There is, of course, nothing wrong with this, but occasionally the student has to un-learn some wrong ideas they thought they knew before getting to my class. It may be possible that the "time crunch of the heavy course load" Mr. Heras experienced was exacerbated by having to undo some misconceptions that he carried into those classes. But more importantly, students that have spent so much time before starting college learning physics do not represent the vast majority of college physics students. It is unreasonable to call out the physics professors for not tailoring their classes to a single student's preferred methods of learning on the

I have some additional thoughts about the context of a few of the Feynman quotes that he included in the letter, but I feel like I've already said plenty.

I feel bad for any student who has a disappointing experience learning physics. But every day is an opportunity to engage in learning and being creative. He has some valid points, but I feel that he is not representative of the vast, vast, vast majority of physics students in the first two years, nor does he have the experience or knowledge of current physics classroom techniques to be criticizing how physics is typically taught.

March 07, 2017

Calc III and me - still thinking about what I learned.

I have an idea for a series of posts where I write down all the stories that I end up repeating frequently to my students.  At the encouragement of @profnoodlearms on twitter, I'm writing down a story that I tell my students (and sometimes colleagues) based on an experience I had as an undergrad taking a math class at the University of Northern Iowa.  Here it goes:

Calc III was the first math class where I needed to copy down everything the prof wrote on the board. It was the second math class I took in When I got to class on the first day, the professor walked in and started to fill up the blackboards with notes. Seeing boards filled multiple times wasn't what was new to me. What was new was that I was in a math class, and the notes had as many full sentences as there were equations. In a one hour class, the professor probably filled four sets of full-sized boards at least three times.

That first week, I just wrote down a few things that I thought were important. I was trying to use the strategy of listening closely, paying attention to what I thought were the most important points and writing those down in addition to anything that didn't make sense. I felt that strategy was compatible with how I had previously learned math, so I figured it should work for Calc III as well.

There was a quiz at the end of the first week. I got the quiz back on Monday of week 2. When I saw how poorly I did, I thought to myself: “Message received!” I changed my note-taking and studying habits. I immediately started copying down EVERYTHING that the professor put on the board. My hand was hurting with the amount of writing I was doing. But, the changes I made in class and in studying paid off. I did much better on later quizzes and exams.

A week or two before finals I was waiting for class to start and I overheard two students talking behind me. “I haven’t been to class for awhile. What’s going to be on the final?” one asked. The other said, “I don’t know, I haven’t been here for awhile either.” I was blown away. I could not comprehend missing a single class and being able to keep up, yet somehow these other students felt they could miss several classes in a row.

By the end of the semester, when I heard that conversation between the other two students, I realized that I was thankful the professor had made it clear I needed to study from the start of the term. It forced me to keep up right from the beginning of the term.  I also learned (in retrospect -- I didn't appreciate it at the time) that sometimes you have to adjust your study and learning habits in order to be successful. The sooner you can make that realization the better off you will likely be.

When I relate this story to colleagues, I have two main points that I think are important:

1.) There is value in giving an assessment and getting it back to the class as soon as possible. Students will have a chance to realize they need to adjust their studying sooner rather than later.

2.) When colleagues talk about how students today don't study as hard as they did in their undergrad years, I point out that probably when they were in class there were more students like the ones I overheard than students who were as studious as they were. After all, we are the ones who became faculty.

So that's it!  Part 1 of N in a series of stories I often tell my classes or colleagues.  Now all I need is a catchy name for this series...


September 12, 2016

Day 11 - PHYS 201 and PHYS 110; A favorite physics puzzle


Last Thursday was Day 11 in Physics 201. We have wrapped up discussing vectors, so the next topic is projectile motion. To start this topic, we got out the ballistic cart apparatus and had the class investigate: traveling on a horizontal track vs. on an inclined track AND dropping the ball vs. launching the ball from the cart.

This is one of my favorite physics puzzles to explore in introductory physics. I heard at least two groups talk about how their trial "didn't work right" because the cart caught the ball when it was going down the incline.  So, they made the angle larger and then tried again - and again were surprised when the cart caught the ball. Great investigation technique here by the students - now we have to work on the analysis.

In Physics 110 we finished up talking about the first five conceptual objectives - including talking about homework questions and practice assessment questions. In terms of new material - we defined longitudinal and transverse motion of coupled oscillating systems. In the previous class we had the air table out (no photos) but this day we used the PhET simulation to explore coupled oscillators:

Normal Modes


Click to Run

We also got out the snaky springs to discuss basic wave behavior.  Working as pairs, the class explored the following ideas:
  • A wave pulse, showing the transfer of energy.
  • Reflection of wave pulses
  • Transverse vs. longitudinal
  • Frequency
  • Wavelength
  • Speed
  • Wave speed depends on the media.
  • Interference.
  • Standing waves.
  • Generation of harmonics.


September 07, 2016

Day 10 - PHYS 201

Today in Physics 201 we finished discussing all the TIPERs related to vectors.  One of the questions involved considering the orientation of the coordinate system.  We had good class discussions about that question.

Also, I shared my version of the "Problem Solving Process" including this poster hanging in the front of the room:

I guess it is clear that I'm not a graphical designer. ¯\_(ツ)_/¯

September 06, 2016

Day 9 - PHYS 201 and PHYS 110

What happened to Day 8?  I forgot and the Labor Day holiday happened, that's what. :/ (Last class was starting vectors, finishing the intro to coding, and doing the first assessment.)

Today in Physics 201 we started vectors in the 8:00 am section and got both sections going with the nTIPERs related to vectors.  I used the PhET simulation for vector addition to get the discussion going, then turned the class loose on the nTIPERs.

Here's one student's artwork with the sim:















I like it!

In the 10:00 am section we had a bit of time to discuss misconceptions from last weeks assessment.  I showed some photos of answers given by students on the assessment.  Surprisingly to me, the students self-identified their own work.  I hope the discussion was positive and productive.

In Physics 110 we looked at coupled oscillators, including getting out the air table for looking at pucks and springs coupled together.  We also finished the work with the IOlab devices and measuring the spring constant with them.  We finished up class by doing some end-of-chapter problems from the first two chapters. First assessment in this class will be next Tuesday.

Onward!

August 31, 2016

Day 7 - PHYS 201

Today in Physics 201 the 8:00am section finished up the TST activities and then did some nTIPERs related to the 1-D motion.

In the 10:00am section we looked at python for the first time.  I stole material from Rhett Allain's introduction to coding - starting with the class looking at constant velocity and constant acceleration motion.  We used trinket.io, which I think I'm going to stick with as long as possible.  Here's the code we started with:


One note - there was a bit of trouble running the code on the classroom laptops. I'm not sure if it is becuase we use Internet Explorer or because I chose to use GlowScript instead of straight python. I'll need to look at this more.