Gas station without pumps

2013 February 12


Filed under: Circuits course — gasstationwithoutpumps @ 21:45
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Grant Wiggins, in his post Autonomy and the need to back off by design as teachers, talks about the need for teachers to withdraw scaffolding so that students can learn to do stuff on their own:

Everywhere I go I see way too much scaffolded and prompted teaching – through twelfth grade. By high school, Socratic Seminar, Problem Based Learning, and independent research ought to be the norm not the exception: you have no hope for success in college or the workplace without such independence. Yet, practically no district curricula are written to signal, explicitly and by design, the need for increased student decision-making and independence in using their growing repertoire as courses and years unfold. Rather, the work just gets harder but is still highly directed. Endless worksheets, prompts, reminders, and ongoing feedback keep co-opting the development of student autonomy.

Unfortunately, the problem does not stop at 12th grade.  A few years ago, I had a particularly weak group of programmers in my senior bioinformatics class, and I was talking with them about their prior education.  It turned out that most of them had never designed a program before—they had coded, but always within a scaffold provided by the instructor, and they had no idea how do divide a problem into sub-problems, which I see as the very essence of engineering and of programming.  Now, if these students had only had the first Java programming class, I would have been sympathetic, but they had had this level of scaffolding all the way through an upper-division class called “Advanced Programming”.  (They’d also had the same teacher for all their programming courses—a good instructor, but one who scaffolds too much, and so a better teacher for the lower-level courses.)

I complained to a member of the computer-science department who cares deeply about teaching, and he promised to speak with the instructor.  Things were better in subsequent years, but this year I was again hearing from the seniors that all their programming courses involved writing code inside scaffolds provided by the faculty.  The gradual withdrawal of support doesn’t seem to have sunk in as an essential part of the pedagogy of the department (or of that particular instructor, at least).

In my circuits course, I’ve been trying to get the students to do things on their own, without having to be led every step of the way.  I’m making some progress on some aspects of the problem (they are no longer asking “is this right?” all the time in lab, but are taking to heart the “try it and see!” answer I nearly always give them), but progress is slow—I still see no evidence of them reading the assigned material before coming to class, or finding lab partners before the day of the lab, or even doing the prelab design assignments without my explicitly telling them to do so.

I do scaffold the lab assignments, with gradually increasing design complexity and autonomy over the quarter.  (Though I’m thinking of re-ordering some labs next year, so that they get more scaffolding on using gnuplot to model and fit data—that hit them too hard in the electrode lab this year.)

I keep expecting them to want to take things into their own hands and come up with things they want to try, but they all seem to approach labs as ritual exercises in performing pre-determined protocols—the legacy of badly designed physics, chemistry, and molecular bio labs. I need to kick them out of this “ritual magic” view of laboratory work.  Having them do designs before coming to lab to build and test them should help (it certainly did with the audio amp lab)—I’ll have to see if I can work that into the earlier labs more.  That might be easier when I split some of the labs, so that measuring a component is done in one lab, then designing with it before the next.

I am worried that some this year will not be able to do the more detailed design of the last three labs (the class-D power amp, the instrumentation amp for strain-gauge pressure sensors, and the EKG amplifier), even if they understand all the concepts needed and can design each block that goes into the final design.

I’ve started to notice that they are afraid to commit to an answer to an exercise or a design problem even when they do, in fact, know how to do the problem.  If they bring that extreme hesitancy to the final labs, where they have to make several design decisions, they’ll shut down before they get the design done.  They have enough resources (op amps, instrumentation amps, resistors, capacitors, PC board space, …) that they don’t need to come up with anything close to an “optimal” design.  There are lots of “good enough” designs that will do just fine for this course.  I think I need to do some more scaffolding of system-level design (like the block diagram for the audio amp), but I need to withdraw that scaffolding before the EKG lab.

I’m hoping that this week’s tinkering lab will encourage more open-ended exploration of a design space for them, and get them over their fear of not knowing the “right” answer. There is no “right” answer for the tinkering lab.  I did explore the space a little to make sure that there were some easy-to-find designs that were interesting—I don’t want them flailing in a design space that is too difficult to explore.  I also provided scaffolding in the form of systematic exercises in modifying the oscillator (like looking at the effect of adding resistors or capacitors between any pair of nodes—it helps that the initial circuit has only 4 nodes). But I’m not going to try to direct the students to any particular design—I really hope they come up with different designs from each pair of lab partners, and that someone comes up with some wildly different ideas that I did not even explore.

I plan to have the students coming out of the circuits course capable of doing some useful electronics design and of writing readable design reports—goals that are much harder to meet than the “pass a test on some circuits concepts” goal of the EE 101 course.  I’ll be pushing the students pretty hard in the class, because I know that they can do it, even if they are still not convinced of it.

I think that these students have been short-changed in the past by teachers who had low expectations of them. Because the bioengineering students take so many intro courses in so many different sciences, they’ve had little time for the advanced courses that might have stretched them—I’m having to do a lot of stretching them all at once, which is not comfortable for them or for me.

I wish we could have a year to develop the engineering practices at a saner pace, but 10 weeks of circuits is all they get, so I’m trying to make the most of it.

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