Teaching Journal Week 5 and 6

Once again, a little behind on the update of the teaching journal.  This week’s excuses: tests in E&M and my introductory particle physics class, in addition to grading the first round of lab reports plus the re-writes.  We’re definitely in the thick of the semester now, but at least I have spring break to look forward to in a week.  Of course, I have to make it through my quantum midterm before then, but that’s a different story.

Now, on to the Teaching Journal:

Week 5

Coming up with a good problem for this type of discussion is difficult.  You want to make it doable, but not too simple.  You want to encourage critical thinking, but you have to give the students enough to grasp onto, or they will freeze up, and look to the TA to tell them what to do.  It’s a tough balance.  That’s why I’m glad that writing these problems is not my responsibility.

I bring this up, because the problem for this week straddled a lot of these lines.  The thing that I liked best about it is also the thing that the students hated the most: it was an open-ended problem, with no set answer.  There were many assumptions that the students had to make, and there were several quantities that they could examine to help decide if the situation presented (involving a superhero, naturally) was realistic or not.

I like this type of problem, because it shows how a physicist has to think.  They are not canned problems, with an answer that you can check in the back of the book.  You can’t even look at the title of the chapter to see what concepts might be involved.  It’s just you, your toolbox of concepts and equations, and your creative approach.

The students hate this.  They ask me what assumptions they need to make, what concepts or quantities I want them to look at, or, worst of all, they ask what equations to use.  I tell them as little as I can, but if I’m too mysterious, I get blank looks, and the students just sit there, telling me they don’t get it.  As a result, I end up directing them down a path more than I would like.  The problem with this is that it perpetuates the idea that there’s a certain way to solve the problem that they need to figure out, and the mysterious cues that lead to my approach can remain obscure.

I wonder if these types of problems would go over better with students who are more intersted in physics for its own sake.

Teaching Journal Weeks 3 and 4

I’ve gotten a little behind on these updates.  What can I say, the Jackson E&M problem sets are really starting to get hard.  Plus, this past week, I had to grade 217 quiz problems from the first quiz.  But there’s no rest for the weary in this business…

Don’t forget the latest installment of Adventures of the Learning Assistant over at Morning Coffee Physics.

Week Three

The discussion session for week three was a group quiz.  The students, working in the same groups that they’ve been in for the past two weeks, work on a problem that will count as the first question of their quiz, which they finish in class the next day.  It’s nice for the TAs, since we don’t have to answer any questions or help the students like we normally do, so we can just relax (or work on problems from Jackson).

The group problem was a pretty straightforward problem in kinematics, and most of the groups did pretty well.  I have to admit feeling somewhat of a sense of pride as I eavesdropped on the students while they were working.  The group problem solving and approach to physics problems have come a long way in a fairly brief time.

I began the lab in week three by handing out a sheet describing my general expectations for lab reports and going over it a little bit.  I then strongly hinted that the lab that day would be the lab that they would be writing up for the first paper, so they should do a good job on it.  In general, they’re not supposed to know ahead of time which lab they’re writing up, so that they’ll be forced to take good data for every lab they do, but I figured it would be helpful to give them a little break on the first one.

The lab itself was on the normal force and frictional force, with the standard block-sliding-down-ramp setup.  Unfortunately, this lab came a little earlier than the topic of friction in the lecture, which always throws students off, even if, as a TA, you cover the relevant issues in the pre-lab discussion.

I haven’t graded many of the reports yet, so we’ll see how that goes.  The first lab report is always going to be pretty bad, as the students try to feel out my expectations and develop an understanding for what sort of things should go into a lab report.  That’s why they get to re-write the first one.  Uncertain Principles has some interesting discussion about the role of lab reports in undergrad labs that you should check out.

Teaching Journal, Week 1

I am a TA again this semester, teaching the first semester of Physics for Biology and Pre-Medicine, which consists mostly of mechanics.  I decided to start keeping a weekly journal of the experience, how well I feel the students are learning, which things are working well, and what I need to do to improve.

Jasper over at Morning Coffee Physics apparently had the same idea that I had, and the class that he is teaching seems to be along the same lines as mine, so I will link to his posts for an interesting comparison.

Chad at Uncertain Principles is doing a similar thing for his modern physics course, so be sure to check it out for a look at what professors go through when teaching a lecture class.

Background Info:

The class is required for a variety of different majors in biology- and health/medicine-related areas, and is in many ways typical of “physics for pre-meds” classes offered at campuses all around the country.  However, the course is nominally calculus based, unlike many versions of the subject that I am familiar with.  (However, students can get by with very little knowledge of calculus, as most of it is contained in derivations, and even then, it’s mostly simple derivatives.)  Also, the professors make some effort to relate the material more directly to biological problems, even if these efforts sometimes fall flat.  I will comment on these efforts as they come up during the semester.

I teach two sections of 17 students each during a two-hour weekly lab and a one-hour weekly discussion session.  The lab topics cover the standard introductory lab topics, but with somewhat of a twist: the labs are supposed to be collaborative problem solving, rather than strictly canned labs.  This essentially boils down to the students having to decide how many data points they must take to confirm or disprove their prediction.  In addition, we’re not supposed to tell the students exactly the equations that their data are supposed to fit, although later in the last semester, I often broke down and derived the equation for them at the beginning of the lab, and explicitly told the students to check these equations.

The discussion sessions are also collaborative problem solving endeavors.  The groups are given a problem that is intended to be too involved for any of the students to solve individually.  Through collaborations, approximations, and some prodding from their TA, the students are to do their best to solve the problem.  If necessary, I will finish the session by reviewing the key topics the students were supposed to think about, and perhaps sketch a solution to the problem.  About every third week, the problem will be the first question of their quiz, which they will complete on the following day.

Grading…

I’ve been grading lab reports for the class that I TA this week.  Sometimes I don’t know how teachers handle it… seeing the same mistakes repeatedly just gives you a terrible outlook on the abilities of undergrads, and by extension, the whole world.  PhD comics has had a running commentary on my thoughts about this:

(I hope this qualifies as fair use of this image.  If not, I will take it down and link to the page.)

Now, in reality I know that they’re not really that bad (the ones I’ve taught, anyway), but grading will make you lose sight of this, at least temporarily.  That’s why I found it was a bad idea to grade for an hour and a half before going to teach my lab.  Doesn’t quite put you in a “go get-em” sort of mood.  I got over it, though.

Grading the First Quiz

The forecast for rain in the morning followed by sunshine turned into rain in the morning followed by more rain and clouds, so I decided today would be a good day to tackle my first grading assignment as a TA.  The physics for biological sciences class had their first quiz, and I was scheduled to grade one of the four problems.  And after four hours of work, they are all graded, and the grades have been reported.

I’ve gotta say, I’m glad that I graded one of the problems on the first quiz, because I have a feeling that easier problems are easier to grade.  The easiest grades to assign are “perfect” and “zero,” because you usually don’t have to spend much time trying to decipher what the student meant to write, what they were trying to do, how close that is to a correct approach, and finally, how many points that work is worth.  Since this was a pretty straightforward unit conversion, there were lots of perfect responses, which I’m sure greatly reduced the amount of time I spent on the grading.

My method was to quickly go over each paper, sorting them into piles that roughly correspond to grades A-F.  Since there were about 200 papers, this took me about an hour, for an average of about 18 seconds per paper.  The first checkpoint was getting the right numerical answer for both parts (which would have taken me even less time if students knew how to box their answers!  I’m not mad, though.  I’m not bitter).  Students with two right answers go in the A pile, students who only answered one part go in the D or F pile, and I have to look a little more closely to separate the B’s and the C’s.