About Me

When not at work with students, I spend my time in my room either reading, calculating something using pen and paper, or using a computer. I read almost anything: from the pornographic to the profound, although my main interests are mathematics and physics. "When I get a little money I buy books; and if any is left I buy food and clothes." -Erasmus

Saturday, January 22, 2011

Peer Instruction and the Need To Walk Around

(I had too much work to post anything this week, and I still have a pile of papers to mark. So here, at last, is where my meandering mind has brought me:)

I use a modified version of Mazur's Peer-Instruction in teaching physics. The idea behind Peer-Instruction is that the traditional lecture-- where the professor writes on the board and talks, with little or no interaction with students-- is an ineffective way of getting our students to learn. A better way is to get our students to read the book, and then use class time for deepening our students' understanding.

During class-hours, I give short summaries of the material and then ask questions using a multiple choice format, where the possible answers are labeled from 0 to 5. These questions, called ConcepTests by Eric Mazur, are intended to get students to talk to each other. To make them effective, the choices have to be chosen so that the wrong answers will also look attractive to students.

When I display a question, I expect all of my students to think silently on their own, without consulting their notes, books or their neighbors. I usually give them around two minutes, and if the question is extra hard, I would ask students who are still thinking to raise their hands. If there are a goodly number, I give an extension of a minute or two.

When time is up, I ask my students to close their eyes and show me their answers. They do this by placing a hand on their forehead and using fingers to indicate their choice. A closed fist stands for zero, a finger for one, and so on. A good ConcepTest gets the class evenly divided; I count the number of students who give each possible answer and I tell my students how the answers are distributed. I then ask my students to open their eyes, show their answers to their neighbors, and then try to convince their neighbors. 

If the class is evenly divided, the convince-your-neighbor phase should get students to shift from the incorrect answer to the correct answer. Students can be very good at convincing other students, so I let them do that. The variety of opinions makes for some interesting conversations. 

 As a bonus, I can immediately tell if the class has a difficulty with a particular topic. I can slow down, change tack, or try other approaches. 

I do have to walk around while my students talk to each other for a number of reasons. I need to make sure that they are actually talking about the question and not using the time for something else. Other times, there will be neighbors who have different answers who don't talk to each other. I then try to get them to convince their neighbor by asking questions. 

Sometimes there will be groups of students who happen to be right, and when such a cluster occurs, I have to go to that cluster and play Devil's advocate. This means I have to do a lot of thinking and reading to figure out how a student, who finds other choices attractive, thinks. It's  hard work-- I have to read the Physics Education Research literature to learn why students find some wrong answers attractive, in order to generate good ConcepTests.  A good ConcepTest is a question that stimulates discussion; it can't be too easy, because no one will talk; neither can it be too hard because there would not be enough correct people to help other people find the correct reasoning.  It seems chaotic, so other people might dislike the method, especially if their idea of a good class is a silent class. 

Many of my students seem to like the format; others see a lot of work because the method requires that they read before coming to class. (You can't please everybody.) One of the happier advantages of Peer Instruction is that it keeps the class awake. If I ask a question, it's easy to see who's asleep-- they don't display their answers when I ask them to. When that happens, I walk to the person and stand beside him or her. It's better than a caffeine shot. 

A confession: the traditional lecture turns out to be easier to prepare for than a class using Peer Instruction. So if you see me giving a traditional lecture, the odds are good that I wasn't able to prepare!

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