July 20, 2010

The usefullness of solution sets

I'm teaching a intensive introductory physics course this month. We cover a quarter of intro physics (algebra based) over a 3 week span. I have been handing out problem sets every day, which students work on every other day in recitation-style sessions.  None of the problems are graded, although the students are strongly encouraged to complete all the problems as part of studying for quizzes and exams.

I was a little surprised to learn that the instructor for the previous course (I'm teaching the middle course) provided complete solution sets to the students. It's not something I had planned to do. So on the first day of class, I was asked if there would be solutions provided.  I agreed to try posting solutions to the course Blackboard page.  Of course, this meant writing out solutions in addition to preparing for the next day. Since I had only written down the answers to the first set and needed to prepare the second set, I posted the answers to the first set and the solutions to half of the second set. By today, I was ready to post a full solution set to third set of problems.

I thought I was being generous.

Generally, I would not provide a solution set to a class.  I believe that students develop a false sense of security by relying on having solutions for all their problems.  Because, eventually I will give them an exam. And there will be no solutions for them. It's a bit like someone learning to ride a bike using training wheels.  You don't go from always using training wheels one day to entering a bike race the next day.

But a few of my students gave some clear reasons why they wanted full solutions.  The reasons ranged from "sometimes I don't know how to start the problem" to "if I'm getting the wrong answer, I can use them to check my work" and everything in between.  So, I'm going to try to post as many solutions as possible.  We'll see how it goes.

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