It has been a while since my last list post, and I feel like focusing more on my mission for this blog. With this in mind, I would like to share a list of my favorite resources for physics teaching and physics education research (PER). Hopefully some of these are familiar, and if you use others, let me know in the comments section.

• MIT Open Courseware
  • A growing collection of course materials from MIT. I find these to be most useful as a reference to see what other students are seeing in Physics. There can be a lot of flexibility in a curriculum and as a young professor, I like to see what other people are doing in their courses. There are a lot of reasons that I can’t use these courses verbatim, but it’s nice to see what is happening at a leading institution.
• Concept Tests (PER@C)
  • One of the easiest things you can do for your course in Physics is to check student conceptual understanding. It is most insightful to pre- and post-test and it’s important not to use these as for-credit exams. This is a test of your abilities as a teacher more than a test of your students… the sooner you come to terms with this idea the better.
• NCSU Concept Test links
  • Another list of concept tests for a wide variety of courses.
• PhET Java-based Concept Simulations
  • Ever thought there had to be a better way to teach a new concept? Sometimes all it takes is a good simulation and giving students a chance to tinker around with some different scenarios. Many of the PhET sims are designed to help students build intuition as a preparation to a more thorough understanding.
• PER Central
  • A general resource for Physics Education Research.

I’m sure there are many other good sites, but these are the ones I end up referring to quite a bit. In the future, I will discuss these topics in other posts, so feel free to contact me with any questions about how I’ve used these resources.

GNU Octave

I have been interested in GNU Octave for a while, although never bothered to play much since I had access to recent Matlab releases while I was at Duke. Now that I am managing my own software budget, and trying to keep it to $0, I have a new found appreciation for Open Source Software. Of course, I like regular free-as-in-beer software too, but I’ve always preferred to use work that is licensed in an open way.

For anyone else who has been hesitant, Octave is now mature enough to be a Matlab replacement. You may even be impressed to find comparable toolboxes… also for free (as in speech and beer). I want to get to know Octave enough to use it in the classroom. At Pacific, we use Maple a fair bit and in the introductory courses, Excel is a stand-by for quick one-off data plots. Both of these tools are well suited to some tasks, but lack some of the features that a package like Octave offers. One definite advantage to Octave in the classroom: students who learn Octave will effectively know Matlab and can add that to their resume.

I expect a certain amount of resistance when it comes to teaching students using a CLI, but honestly, it can’t be as frustrating as some of the strangeness in Maple’s document interface. I like Maple for doing integrals, algebra, and plotting functions, but generating data and importing data to process aren’t as much fun.

I’ve also been looking into SciPy, a python-based toolset with a Matlab feel (less a few exceptions). At this point, I find SciPy to be a good tool for me as a programmer and researcher. However, as a teaching tool, it requires too much familiarity with Python and programming in general. The IPython shell, and some other offerings like the Enthought Python Distribution, have the potential to change that. With matplotlib, IPython can be pretty close to Matlab; the biggest difference is how to deal with arrays and ranges.

The best part about it, is that Octave Forge now packages Octave.app (and Gnuplot.app) into drag-and-drop installers. Since the mac is my platform of choice (and the platform used in one of our teaching labs), this is a big deal for me. Note: the Gnuplot.app is located in the “Extras” folder when you download Octave.app. Simply drag both into /Applications and you are off to the races.

photo credits: ladyada @flickr

This fall Physics 364 (Electronics) will have a project component. Pacific has chosen Sustainability as a campus-wide theme for this academic year, and with this in mind, I will encourage the class to consider projects that explore the application of technology (electronics, physical computing, etc.) to improving sustainability. This can be challenging as technology is often viewed as a culprit in the current global crisis. One major challenge for the project, is to transcend this view and demonstrate ways technology can help us in a global sense.

I’m always open to suggestions, although I do have a few ideas on ways electronics can be applied to alternative energy (power system control and optimization). One example would be an automated solar panel gimbal that would optimize the direction of the panel for highest power generation. I’m sure these exist already, but it would be a fun thing to make. I also know of at least one well-documented project using an Arduino to automate a home garden (the Garduino, see MAKE 18). If you’ve run across anything that fits the bill, or would inspire this sort of project, please let me know.

A brilliant tip on how to mash up CiteULike and BibDesk (two of my favorite tools). It helps that my article-search workflow is identical to the author’s. If you browse and post to CiteULike, this is a great way to bring those articles into BibDesk.

Academic Productivity » CiteULike + BibDesk: Sync your references and live smarter

Take a look at physics.aps.org for my Viewpoint article on Efficient All-Optical Switching Using Slow Light within a Hollow Fiber by Bajcsy et al. The work demonstrates an all-optical switch that was built by inserting cold Rubidium atoms into the hollow core of a photonic-crystal fiber. These fibers have been used in a wide range of nonlinear optics experiments and this is yet another interesting application.

I am wrapping up  my first year and recently faced the most difficult decision of my time here. Of course, there have been easy decisions and hard decisions all year, but they were all things that I expected from deciding to fail a smart student who turns in no homework to how do I respond to the top student who is still worried about passing despite having a 99.4% average. Many challenges arise in a given year, but last week I had to grapple with a tough one: how to tell a student that despite their academic strengths and interest in my research, I don’t have enough research positions in the lab this summer.

To elaborate, I have funding for three summer students. Two have committed and there are two more who are very interested. I have to choose between two students who are both sophomores, both do well in class (almost identical scores), both have recently declared as physics majors; who do I turn away? I realized that out of respect for their summer plans, I needed to decide quickly to give them a chance to find something else. Telling a deserving student that they can’t participate in research is not something I’m good at, but I guess it is part of our “current economic climate.”

I can always hope for unlimited funding in the future, and perhaps avoid the same situation. I’m very glad that I didn’t have trouble finding good students, but I would love to give everyone an opportunity to participate in research. It was such a pivotal experience for me, I hate to turn people away for silly reasons like money. With that, I’ll toast to an increased budget at NSF and the hope for increased opportunities for students; after all, they are the reason I’m here.

I’ve decided to use the Arduino in my electronics class this fall. The Arduino is an “open-source electronics prototyping platform based on flexible, easy-to-use hardware and software.” Even from the description it sounds like just what an electronics course needs. I finally had some time to tinker with it today, and after a few minutes I had it’s LED blinking away, and then after another few minutes it was an oscilloscope. A few minutes later it was playing a pulse-width-modulated (PWM) melody. Not bad for an hour’s work.

With a little inspiration, and my new-found confidence, I took to my first project in hopes of having a little demo to show the intro students to recruit them for my class in the fall. An hour and a half later (including fielding questions about homework and our exam tomorrow) I had a photo-resistor theramin up and running. The basic idea is to use a photoresistor as half of a voltage divider and tell the Arduino to read the voltage and output a PWM tone whose frequency depends on the voltage. This way the pitch can be controlled by blocking or unblocking the light at the photoresistor.

int speakerOut = 9;

void setup() {
  pinMode(speakerOut, OUTPUT);
}

int tone = 0;
long input = 0;
int maximum = 500;
int minimum = 400;
float range = 100;

void loop() {
    input = analogRead(0);
    if (input > maximum) maximum = input;
    if (input < minimum) minimum = input;
    range = maximum-minimum;
    tone = 9090*float(1-float((input-minimum)/range));
    //tone is the period, so large means high frequency.
    // when using analogRead, this means a high voltage gives a low sound.

    digitalWrite(speakerOut,HIGH);
    delayMicroseconds(tone / 2);

    // DOWN
    digitalWrite(speakerOut, LOW);
    delayMicroseconds(tone / 2);
}

Enjoy!

Over the next few months I am hoping to develop a course on the Physics of Sound and Music. Although this course isn’t on the books yet, it has been offered in the past, and it would fit into the new core model at Pacific. We have adopted a program that replaces the old “pick two courses from each column” breadth requirement. The new model is based on focal studies, which are course clusters containing coherent, cross-discipline content. To bring more non-majors through the department, and also to extend our overlap with the music and arts departments, it would work well to have a sound and music course, and a light and vision course.

For the time being, it looks like we will split up our two four-credit non-majors courses into four two-credit courses. This will let us tailor the topic more directly to the students, and in particular, to the focal study they elect to take. The result of this split will likely be: sound and waves; optics and photography; atoms, electrons, and fields; and mechanics. There are some obvious things missing, like thermodynamics, so we are going to have to consider this approach carefully. I’m happy to hear from people who have tought or taken sound/music classes from physics departments. Any things you liked or didn’t like?

There was one reason I used Safari rather than Firefox, and it has recently evaporated. I read a lot of PDF files (>20 per day browsing papers etc) so I was tired of the extra files accumulating in my download folder. You may know that Safari uses Appe’s PDFkit to display PDF files in your browser window, no muss no fuss. Until recently, the options in Firefox were the Adobe plugin (slow) or a privately developed solution tht requires an Intel machine. Enter a fantastic add-on, available at firefox-mac-pdf – Google Code.

Last semester, in Waves and Optics, we discussed Rayleigh scattering. I described some simple examples, including the famous blue sky, and orange sunset. Earlier in the semester, I had coincidentally noticed that Squirt soda in a clear glass tends to be a little blue in hue, and not surprisingly, looks orange if held in front of a white light. So it turns out that in addition to milk drops in water, Squirt soda also exhibits this effect.

Later in the semester, one of the students brought in a bottle of squirt to test my suggestion and did the demo for the whole class. After a little tinkering, it works best cut in half with water. This is for a large glass, so if you want to use a fishbowl or tank, you may have to dilute it even further.