Large lecture inquiry: How to engage students in the practices of science

by Stephanie Chasteen on March 11, 2012

I’m behind in my blogging from the AAPT Winter Meeting, but better late than never.

Fred Goldberg

I had the pleasure of meeting Fred Goldberg at this meeting, an influential teacher and education researcher.  Even without knowing that he’s an important guy, you can sense his charm and intelligence like a warm glow.  He’s very thoughtful and kind, and even gave me some useful feedback on my clicker workshops, suggesting that I ask participants to write questions focused on a particular pedagogical goal (such as “motivating to learn”) rather than around a content learning goal (e.g., “be able to apply Gauss’ law in conditions of high symmetry.”).  I just tried that technique today, and it did seem easier for people to try writing around pedagogical goals.  Thanks Fred!

But what I want to write about here is a talk he gave during PhysTEC, prior to AAPT, about facilitating large-lecture inquiry.  You can see Fred’s slides on the PTEC site here.  This is something that has been really bothering me for a while; I know all these great hands-on inquiry activities, and there has to be a way to do some of these in a lecture setting.

Fred has been heavily involved in the development of the PET and PSET curricula — small teacher-preparation classes that use small group and class discussions with hands-on labs and computer-based experiments and simulations.  The focus is on constructing and evaluating explanations based on inquiry experiences.  These are powerful ways to learn science , especially for teachers who will be helping the next generation learn how the world works.

To give you an example, one activity has students rub two nails together and notice that they are magnetized (they’ll pick up paperclips, etc.).   So what, they ask the students, do you think is going on?  Usually students will hypothesize that all the South poles (S) are on one end and all the little North poles (N) are on the other end.  Below is a drawing (from Fred’s talk) of this model:

So, what will happen if you cut the nail in half?  With that mental model, students will predict that each half piece will be either N or S.

Images (c) Fred Goldberg

They can then test that prediction, cutting the nail with strong clippers. And they’re typically surprised to find that each half acts like a little magnet.  They keep cutting the nail in half, thinking that they’ll eventually get to a small enough piece that they’ll have one N piece and one S piece.

But at a certain point, they realize that they can’t continue.  The pieces are getting too small.

So then the teacher brings out a test tube full of iron filings and they see what happens to the filings when exposed to a magnetic field; they each line up with the field.  This is a metaphor for the true model of magnetization inside the nail, where there are tiny magnetic domains that line up with the field, as below.

This is a powerful way to develop the dipolar model of magnetism, but takes about 5 hours working in small groups.

So, the question he asks, is “how can we engage students in large classes in scientific practices, like hands on experiments, drawing on evidence, developing models, evaluating explanations, and supporting arguments with reasoning?”

He’s working on developing large class versions of the PET and PSET cirricula:  Learning Physics (LEP) and Learning Physical Science (LEPS).  In these curricula, he uses instructor-guided whole-class inquiry, using videos of the different demonstrations where appropriate. For example, one might show a video of a cart being pushed, rolling, and coming to a stop.  At what point do students think the finger lost contact with the cart?  This is a great way to lead into class questioning and inquiry.  It seems you have to be rather clever with your videos to choose something where there is an essential question you can ask that will help students grasp a central concept or mental model.  I’ll note that we’ve done things like this with the PhET simulations, where you show a simulation and then ask students to predict what will happen if we do XYZ.  We don’t do that much with creating models of the physical processes, however — the simulation often represents a model itself.

In LEP and LEPS they also give groups small bags of materials so that they can do a few simple experiments at their desks.  For the nail magnetization activity, one member of each group takes a picture of the group sketch of their model of magnetism on their cell phone and emails it to the instructor.  How clever!  Now there is a way for the instructor to discuss various student ideas, but without necessarily circulating to each group in a large lecture.

He uses a lot of clicker questions so that they can get a sense of where the whole class is.  For example:

According to your group’s model, when the rubbed nail is cut in half, how would you describe each half piece?

Use a lot of clicker questions so that we can see where all class is.  For example:

According to your group’s model, when the rubbed nail is cut in half , how would you describe each half piece?

  1. Each piece is one ended
  2. Each piece is two ended
  3. One half piece is one ended and one is two ended

Choice (1) is the canonical wrong answer, but some answered (2) because this was an idea they’d heard before.

Each lesson is about 25 minutes long, so it can fit into either 50- or 75-minute lecture periods.  In contrast to the small group version, this version of the magnetism activity took about 3 hours.

This took about 3 hours, more guided.  For some aspects of the course, such as written materials, they used the calibrated peer review developed at UCLA, http://cpr.molsc.ucla.edu.  On the exam, they would typically give students a hypothetical explanation of something and ask them to evaluate that explanation.

I’m really excited by this new work and look forward to seeing more of it.  You can see Fred’s slides on the PTEC site here.  The curriculum is under construction but you can learn more about LEPS here.

 

{ 1 comment }

fengörsel October 19, 2012 at 9:21 pm

güzel bir site olmu? tebrikler…

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