Confused at a higher level

The view from Carleton College's physics department

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We’re looking for a 2-term visitor

Posted by Arjendu on December 11, 2014

Please let students/post-docs know:

The Department of Physics and Astronomy at Carleton College is seeking applications
for a temporary, two-term position at the Assistant Professor level for the 2015-2016
academic year. We seek a recent PhD in physics or astronomy with a strong commitment
to teach in a liberal-arts environment. The position will involve teaching 4 courses over
two terms (either September 1, 2015 through mid-March 2016 or January 1, 2016
through mid-June 2016). The ideal candidate will be comfortable teaching astronomy as
well as physics. There may be opportunities for involvement of undergraduate students in
research, but it is not required for this position. Carleton College is a highly selective
liberal arts college with about 2000 undergraduates located 45 miles south of
Minneapolis/St. Paul and is on a three term per year schedule. Our eight-member
department strives to provide a challenging yet supportive environment for our
enthusiastic and intellectually demanding students. For further information on the
department, visit our web site at
To apply, complete the online application by February 15, 2015 at . The online application should include a cover letter,
curriculum vitae, and a statement of teaching experience and how it has influenced your
teaching philosophy. In addition, you will be asked to submit contact information for
three individuals who can serve as references.
Carleton College does not discriminate on the basis of race, color, creed, ethnicity,
religion, sex, national origin, marital status, veteran status, actual or perceived sexual
orientation, gender identity and expression, status with regard to public assistance,
disability, or age in providing employment or access to its educational facilities and
activities. We are committed to developing our faculty to better reflect the diversity of
our student body and American society. Women and members of minority groups are
strongly encouraged to apply

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AAPT recommendations for undergraduate physics laboratory curriculum

Posted by Melissa on November 23, 2014

Over the past year and a half, I’ve had the opportunity to work on a subcommittee of the AAPT Committee on Laboratories to develop a set of recommendations for undergraduate physics laboratories, both introductory labs and labs beyond the first year.  Working on this project has been a lot of fun, and I hope our report provides a useful and flexible framework for faculty at a variety of different institutions.  The report was just endorsed by the AAPT Executive Board, and it’s now available online. While the written report is finished, the members of the committee hope to find  ways to allow lab instructors to continue the discussion about, and contribute specific examples to, the matrix that is at the end of the document.

If you find yourself needing to escape from that particularly annoying uncle or cousin over Thanksgiving, I’d encourage you to step away from the festivities and read the report!

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Remembering Piotr

Posted by Melissa on October 28, 2014

This coming weekend my alma mater is celebrating the life of Piotr Decowski, a beloved member of Smith’s physics department who passed away in May. Sadly, I won’t be able to make it back to Northampton for the symposium. Piotr made an indelible mark on me. I had only one class with him while I was at Smith — Modern Physics in fall term of my first year. Just out of a high school, unsure of my next steps, possibly interested in physics, but also deeply attracted to history and philosophy, I entered Modern Physics filled with equal parts unbridled enthusiasm and immense uncertainty. Would my high school physics background prove sufficient as I jumped into a 200-level college physics course? Did I really want to study physics, and did I even know what physics was? (I come from a family that has a strong humanities bent to it.) Would I fit in at Smith and could I ever live up to the legacy of outstanding women that the institution had produced?

Piotr was exactly the professor I needed to encounter in my first encounter with Smith physics. He was filled with joy and gentleness, and upon setting foot in his classroom, one could not help but share the wonder at just how amazing the physical world could be. Physicists can be egotistical people, who like the exclusivity of the club to which they belong. Not Piotr. He was warm and welcoming. The beauty, the strangeness, the wonder of physics were at the center of Piotr’s classroom. I remember Piotr with an eternal twinkle in his eye. I felt like I was walking with a guide, who, despite significantly more experience and knowledge, still held a quiet, joyous wonder about the world. And that joyous wonder was contagious.

Near the end of my semester in Modern Physics, the department organized a dinner before one of the Five College physics symposium talks. I think the dinner was at Piotr and Ineke’s house, though I’m not certain. It was November, a week or two before Thanksgiving break, but dinner consisted of turkey and cranberry sauce and all the Thanksgiving fixings. Eating Thanksgiving dinner with the junior and senior majors, faculty, and classmates in Modern Physics, I distinctly felt that I was “home”. And Piotr was the person who had welcomed me into that family. More than 15 years since graduating from Smith, I still have not found a group of physicists that feel so comfortably like family as the Smith physicists, and so this weekend my heart will be with the Smith physics family as they gather to remember Piotr.

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Old Friends New Territory

Posted by Arjendu on October 27, 2014

So I am currently at Quantum Optics VII a formerly Latin American Quantum Optics conference that currently is about 1/2 not Latin American and mostly not about Quantum Optics (though it is about quantum mechanics, which is is how I landed up here, invited to give a talk about my recent work).

This conference is organized by, among others, Juan Pablo Paz, who I’ve known for a long time, but met only a few times, and so it’s been nice to see him, and catch up even if briefly as well as with other people I’ve gotten to know from conferences and talks over the years like Andre Carvalho, Carlos Pineda, Martin Plenio … and I know Aephraim Steinberg is around, so all that should be fun as well. This is also my first trip to South America (though so far I’ve barely seen anything particularly given the generic nature of airports and hotels of a certain kind) and it’s my first time pretending to be a quantum optician.

So. The usual term-time conference stuff: Tired trying to get things set up so I could leave for a bit, and from the long long haul here, somewhat — make that very — nervous about my own talk, looking forward to immersing myself in ‘state of the art in quantum mechanics’ after a few months hiatus, and trying to stay caught up on professional and personal emails in the post-conference evenings. But it was hard to resist the invitation, and I am glad I’m here.

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Teaching without writing

Posted by Arjendu on October 24, 2014

Last Sunday I dislocated my right shoulder. Nothing dramatic, no fistfights over the meaning of the 2nd law or interpretations of quantum mechanics or priority for research, nor because my students were mad at me for my supposedly short exam that turned out to be not-so-short … just a simple fall coming up some stairs, combined with a previously unstable shoulder (6 dislocations in the past) that a surgery didn’t seem to have made *that* stable. It was painful for a bit but once it got shoved back in at the ER (‘reduced’ in the medical terminology) I barely felt it.

But I did lose some time sleeping off the anesthesia, and have had to leave my arm in a sling for a while. I’m right-handed, so this made it very difficult to write or grade or do that Ph.D. dissertation external examiner thing I had scheduled for the weekend. I tried ‘voice-to-text’ software, and that wasn’t too bad for most things, but (a) it made me speak like an American — I haven’t purchased the fancier trainable software — and (b) had no idea what to make of words like ‘non-Markovian’, or any other technical jargon I was using around. I managed, somehow, for all those things, and leaned on my family greatly — it’s a nice place to be in life when your child can do your laundry for you instead of the other way around! The silly accident made an already crowded schedule just that much harder for the last few days.

But you know what wasn’t an increased challenge, really, not much anyway ? Teaching my thermal/statistical physics class. This week, I’ve walked in with the printout of questions the students have generated overnight from the reading, told them to go through the questions AND then repeat their transit over the chapter in small groups. They throw questions out to me when needed while I wandered around the class kibbitzing during the discussions, and periodically summarized verbally the central points of each section. It means we’ve marched just fine through the material, finishing with working on some problems in the same small groups. It’s helped slightly that for this part of the term I have the students signed up for short teaching presentations (to get them ready for larger presentations as part of their senior graduation requirement). So I’ve had students do a (previously-prepped) derivation on the board for me as needed. But that was only about 5 minutes out of each class.

Carleton physics students are so used to this sort of reading+questions+classroom-discussion-based format (and I am so used to it myself) that things seem just … normal. And it’s far cry from the ‘chalk and talk’/lecture-intensive world from my own undergraduate (and actually, graduate school, too, now that I think of it) days. I have no real idea how rare this sort of format is for the bulk of physics teaching out there in the world today, but I’d bet it’s rare enough.

You know what was challenging, surprisingly enough? Talking to my collaborators in California via skype. Turns out I use my hands to argue a lot more than I think I do, when it’s about dynamical systems and phase-space in particular. They thought it was pretty funny when I’d get frustrated by my inability to convey what I wanted using only one hand.

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Experimenting with electronic lab notebooks

Posted by Melissa on October 7, 2014

I’m using tomorrow’s Global Physics Department discussion of electronic lab notebooks with Ed Price as a kick in the pants to finally write the post on electronic lab notebooks (ELNs) that I’ve been meaning to write since last spring. Unfortunately, Wednesday nights are busy on the homefront so I’m not sure I’ll be able to join the GPD discussion. Instead, I’ll throw out a few thoughts here, and hopefully catch the GPD recording later.

Last spring I taught our advanced lab course (Contemporary Experimental Physics), which is typically taken by majors in the spring of the junior year. For the first time, I asked students to keep an ELN instead of a paper lab notebook. I spent quite a bit of time exploring options (OneNote, Evernote, GoogleDocs) before finally settling on LabArchives. Although not free for students to use, students only pay $10 for an account, which is not that much more costly than  a traditional paper notebook, and I found the software features and the technical support from LabArchives to effectively meet my needs.

Why did I make the switch to ELNs?

I’ve heard more and more professionals (in national labs, in companies, in university research labs) say that they are using ELNs, and I want to prepare my students for type of experiences that they will encounter in their professional lives. However, I also switched to ELNs for a variety of pedagogical reasons.

  • It’s easier to collaborate with ELNs. Students in a lab group can share their lab notebooks with each other and write comments in each others notebooks. And in some experiments, where each group builds on the work of previous groups, students can access the lab notebooks of those who went before them, without needing to physically borrow the notebook. Additionally, the software logs which students are making comments, and when, so I can see how each member of a group is contributing to the lab notebook.
  • ELNs make it easier for me to keep track of what students are doing. Particularly in the advanced lab course, where final projects take four weeks, it’s inconvenient to collect the lab notebooks from students to see how things are going. (Plus,I hate lugging around a stack of 20 lab notebooks!)  With ELNs, I can check in on the lab notebooks at any time, and for extended projects where much of the work takes place outside of designated lab time, ELNs allow me to track project progress in a less intrusive manner.
  • Because the software time stamps everything, I can tell if the lab notebook is a genuine record of the work as it is being done or if the lab notebook is filled out after the fact.
  • More and more work is being done on the computer so why not keep the records electronically.  It seems strange to require students to print out spreadsheets and graphs and Mathematica notebooks to paste them in a paper notebook.

What worked well with the ELNs?

  • All of the above: easy sharing of notebooks with peers; easy instructor tracking of student contributions and project progress, particularly for work done outside of scheduled lab time; more real-time record keeping. Perhaps most importantly, I sensed that the notebooks were a more genuine record of student work than what I have seen with physical lab notebooks.

What didn’t work well with the ELNs?

  • The lab notebooks contained fewer sketches (particularly sketches of the experimental set-up, physical models, etc) than a traditional lab notebook. Next time, I am going to encourage students to do more sketching on whiteboards, or on paper, and then use their phones to take pictures of those sketches. LabArchives has an app for phones that makes it easy to upload pictures directly into folders in your LabArchives notebook, but I didn’t highlight that feature and few students used it.
  • Although I looked at the student notebooks several times each week, I didn’t comment in the notebooks frequently. More often, I would use my observations of items in the lab notebooks to start conversations during the scheduled lab time. However, in course evaluations, students mentioned that they would have liked more comments from me in the lab notebooks.

What am I ambivalent about with the ELNs?

  • I asked students to bring their own devices to lab for their record-keeping.  Depending on the particular experiment (and the associated  instrumentation, lab space, etc), at times it was awkward to have three laptops close by so that each student could be taking notes in their lab notebooks. As tablets become more widespread, I think this issue will become less of a concern.
  • Although LabArchives allows students to export their notebooks as a PDF so they can have a “permanent” record of their work, I’m not sure how many of my students actually exported their notebooks. Once again, I could have helped address this issue by being more insistent that all my students export their notebooks at the end of the term.

What features was I looking for when selecting an ELN?

  • Each student had to have his or her own notebook, with the ability to share the notebooks with others in the class. I also wanted students to be able to comment in each others notebooks, as well as for me to comment in student notebooks.
  • I wanted to be able to populate the lab notebooks with some materials at the beginning of the term, and I wanted to be able to push out materials to the student lab notebooks during the course of the term, without overwriting anything that students had done in their lab notebooks.
  • Since students were using their own devices, the software had to work on laptops and tablets with a variety of operating systems. I also wanted the option for a phone app so that students could take photos with their phones and import them easily into the notebook.
  • The software had to be able to handle equations.
  • I didn’t want my students to pay much more for the ELN than the would have for a traditional paper lab notebook.

What did the students think about ELNs?

  • Students initially had a hard time figuring out how to organize the ELN, but eventually, each group came up with a slightly different organizational approach. Once that was established, the student response was mostly positive.

I will certainly continue using ELNs when I teach the advanced lab course, and I plan on sticking with LabArchives unless I find something that is a better fit. However, I know that discussions about ELNs elicit strong feelings and I’m interested in hearing about the experiences that others have had. Let me know in the comments if you have you used ELNs in your classes or research lab. If so, what software did you use and how did you like it?  Finally, consider joining the GPD discussion on Oct 8th at 8:30 pm CDT about ELNs.

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The 2nd Law of Thermodynamics

Posted by Arjendu on October 3, 2014

The 2nd Law of Thermodynamics: Without it there would be no time, no birth, no death. It cannot be ‘derived’ and hence is an article of faith, and we follow its dicta every day, every minute. It is the source of some of the more enduring mysteries of physics. It is the reason for any ‘energy crisis’ we might face in the future. It is also my favorite candidate for divinity within physics.

You can present the 2nd Law in a relatively straightforward manner, but it gets very puzzling and confusing if you think about it for long or in detail. I asked my students to write up a non-technical version of the 2nd Law and share it with someone who didn’t know about it*. Most found it an interesting exercise, particularly in showing where the weaknesses were in their understanding (‘not being able to hide behind the technical material made me think really hard and carefully’).

One semi-colloquial version of the 2nd Law that I like is ‘S happens’. So it’s a rather profane divinity we’re talking about, and generally applicable, eh ?

So here I go, glad to have survived another week. Starting to get the rhythm of teaching again, but boy it’s exhausting.

(* Yes, my facebook friends know there was more to it than this)

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Have I recently said how much I love this gig ?

Posted by Arjendu on September 26, 2014

I huffed and puffed my way on bicycle up the 2nd Street hill on the way in to teach this morning, coming in early enough that there was barely anyone else on campus. I wasn’t really focused on the sights, typical enough for an American college campus: Trees changing color, calm greens, expectant academic buildings. I was distracted by how I was going to approach today’s class, which was on the 2nd Law of Thermodynamics. The actual content was simple enough, and could be summarized easily, and in fact I had barely enough material to cover 2 whiteboards when I did write it down in class. But I knew the ideas were troublesome, and needed careful discussion, since as always the students had emailed questions about the readings (the last one had come in after 2AM, which meant that at least one student wasn’t going to get much sleep before my 8:30AM class) so I knew what the lay of the land was (and none of it was surprising, really). In one of my pockets lay a handful of dice, which were going to be used in one of my ‘demos’ about ‘typical states’. And, well, given how much I have enjoyed understanding this deeply subtle and immensely powerful idea that governs the behavior of the Universe (‘Entropy increases’), perhaps it wouldn’t be surprising to characterize my state of mind, as I pulled in to lock my bike and catch my breath, as: happy. Happy to be struggling with these ideas, happy to be anticipating my class of majors as I get to know them, happy that the book I had gambled with seemed to be doing fine. Happy.

It’s been very fun but challenging as well to return to the Carleton classroom. So I would be lying if I didn’t mention that, of course, I was happy that it was Friday.

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Thermodynamics and statistical mechanics

Posted by Arjendu on July 19, 2014

This fall I will be teaching Carleton’s junior level thermal/statistical physics course. It’s an annually offered course and for various reasons has been one of the courses furthest from equilibrium in our Department. That is, it has always been at least partly or fully required (let’s not get into how we manage to partly require something, that’s a whole different story) but its format, placement in the curriculum, instructor, syllabus: all of those state variables have fluctuated greatly since I came to Carleton.

The topic itself allows for such a wide variety of interpretations and paths. Looking at its place in the curriculum, the possible uses to which this knowledge will be put in future classes or professions, my sense of the course is that it must follow and connect both the macroscopic empirical approach of thermal physics and the microscopic bottom-up approach of stat mech. And also, even though I’ve mainly been presented this material as a ‘methods + models’ theory course, it’s increasingly clear to me that it must include some real world considerations (such as energy efficiencies, etc).

So — as I return to the Carleton classroom after 4 years away — the questions I have been brooding over include: How should I teach it? What should what path do I take? I’ve taught it once before but that was seven years ago, and I’m definitely starting from scratch in building a syllabus, and that almost always comes down to selecting a text. All this apart from format — how much lecture versus discussion? what kinds of open-ended problems, and when?

Here’s where I stand: I have personally been lead through some wonderful treatments (the Kittel and Kroemer version as a 3rd year student at St. Stephen’s College with the great Dr. Popli was where I had the most fun, and I am familiar with paths through Reif, Pathria, etc, etc). I also spent about 5 years as part of the Center for Statistical Mechanics at Austin though my own research has intersected with statistical mechanics on rather abstract issues about the behavior of entropy and signatures of chaos and irreversibility and decoherence, etc. If anything, as a (semi-)specialist, it is harder to gauge what topics should be considered absolutely necessary, and I am less clear about what is intuitive (I don’t remember the bliss of my ignorance that well anymore!), what the right pace is for going over fundamental laws versus doing applications, etc, etc.

In the last few weeks I have been reading/skimming multiple textbooks, reading up on approaches, getting a sense of pace. My short-list for texts — and it’s likely all three books will remain open on my desk for the next few months — are Kittel and Kroemer (‘Thermal Physics’), Schroeder (‘Introduction to thermal physics’), and Stowe (‘An Introduction to Thermodynamics and Statistical Mechanics’). Whichever I go with, it’s going to be a close call and the choice depends — whether I like it or not — as much on things like what works best as the core for my 9.5 week term, and where Carleton students are in particular, as on the approach. Despite K+K’s name, it’s really much more stat-mechy in its approach, which is both where I am happiest and also what I am trying to avoid. Both Schroeder and Stowe weave stat mech and thermo together, and I think the integration is more seamless but also idiosyncratic in Stowe. I have also considered doing one book as the core text and another as supplemental reading, but that’s rather unlikely.

Something I like to do when brooding over a course like this is to find a good layperson’s treatment first if possible, to remind me what it’s all about, and to broaden my vocabulary for connecting equations and intuitions. I picked up Peter Atkins’s slim 100-page treatment (“The Laws of Thermodynamics: A Very Short Introduction”) and got through 3/4 of it while on idle during some parentally required down time. I’d recommend it to anyone looking for an excellent stripping down of thermodynamics and statistical mechanics to the absolute basics. He moves between the microscopic and the macroscopic very nicely. And his chemists perspective is really helpful for me in ‘keeping it real’.

The ideas, rules, and relationships of this area are among the most subtle and counter-intuitive and yet foundational. What’s more foundational than the Second Law, about which Einstein said: “It is the only physical theory of universal content, which I am convinced, that within the framework of applicability of its basic concepts will never be overthrown” ? And yet one bumps into these ideas when thinking about day-to-day issues such as engines and work and chemical reactions.

It should be an interesting fall, particularly given that I will be doing an Argument and Inquiry Seminar on energy issues at the same time.

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Ramblings on teaching measurement uncertainty

Posted by Melissa on July 15, 2014

A couple of my colleagues and I have curricular development funds this summer to explore how we can better integrate computational and experimental activities in our curriculum. One of the topics that came up in our discussions yesterday was uncertainty: teaching propagation of uncertainty, getting students to appreciate what the uncertainty associated with a measurement really means, and the role of uncertainty in computational as well as experimental problems. As someone who teaches a lot of lab courses, I can’t tell you how often students will see two values, and their associated uncertainties, and say, “These values don’t agree because they don’t overlap within the uncertainty.” Argh!

As a department, we could probably do a better job making the discussion of uncertainty more coherent throughout our curriculum, and I know that I could do a better job of reinforcing the importance of the uncertainty in the classes I teach. One of my colleagues writes homework and exam problems regularly that require calculations with uncertainties. On the other hand, when I am not in the lab, I rarely include uncertainties in the problems that I ask students to tackle, which I think sends a message that uncertainty is peripheral.

Looking at the broader physics education landscape, when it comes to teaching uncertainty, there seem to be two groups: those who have heard of the current international standard (Evaluation of Measurement Data – Guide to the Expression of Uncertainty in Measurement – known as GUM and published in 1993) and those who haven’t.  GUM only appeared on my radar two or three years ago. This spring was the first time I introduced students in our advanced lab course to the GUM method for handling uncertainty.  If you aren’t familiar, Andy Buffler and Saalih Allie at the University of Cape Town and Fred Lubben at the University of York have developed some nice curricular materials for introducing the GUM approach in introductory physics classes (Curriculum and TPT article).

I wonder if GUM will ever gain a more significant following. It hasn’t made many inroads beyond the metrology community, and among educators, the implementation is not particularly widespread, despite the clarity with which I think it helps students navigate the maze of measurement uncertainty. For all you physics educators out there, have you heard of GUM? Do you use it in your curriculum? And if you do, what do you see as the benefits and drawbacks?

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