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My evil plot *July 30, 2010*

*Posted by mareserinitatis in education, physics, science, teaching.*

Tags: graphs, physics, TA

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Tags: graphs, physics, TA

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I have TAed four different labs throughout my academic career thus far: physics labs for soft-science majors, optics core lab for physics and engineering majors, circuits I, and introductory geology.

The physics labs were my first experience TAing, and it was a bit of a shock. I hadn’t realized how difficult some of the students would find physics. I was especially shocked as these students were primarily bio- and social science. While I didn’t expect them to be extremely numerically inclined, I was surprised at some of the basic skills they were lacking as potential scientists.

In light of the recent calculator discussion, I thought about another issue that’s moderately related: plotting graphs. My first semester of teaching physics lab, I was pretty lenient about how I dealt with data plotting. A couple students would ask to run to the library so they could plot their data and hand back the lab before they left for the day. (These were the kind of labs that required taking data and short answer, not a full-fledged written report.)

I was so frustrated with my students after the first semester, I completely changed my focus. My students, if they learned only one thing from being in my physics lab, better know how to make and use a graph. As science majors, they are going to need to know how to read charts, assays, histograms, etc. They need to understand how graphical models of data are read and used to interpret results.

I began the semester with a handout that showed everything I wanted on graphs: individually labeled data points, best fit line, equation for the line, and labels including units. I went through this example plot in meticulous detail. Thereafter, each plot was worth 30-50% of the lab grade.

Yeah, harsh. And not wildly popular among the students.

One of my computer-using students didn’t seem to have too much difficulty with the new procedure, but his labmates did. Even though I had gone through a very detailed explanation of how to find the slope of the line, they still struggled. They were used to using the equation-fitting function in Excel because their lab partner had shown them how.

The rest of the class fared no better. The first couple weeks were filled with questions about how to draw a best-fit line and how to determine the slope of the line. I am still shocked that somehow the majority of students missed this information in high school. By the end of the semester, I’m pretty sure there were still a couple students who hadn’t figured it out. I think that for the most part, however, the endeavor was generally successful in terms of getting them to understand how graphs are supposed to work. I’m not as sure about how they did on the interpretation of such data.

The experience also made me think more about the purpose of science courses in university education. I realized that semester that a lot of students would walk out of those classes only being glad that they never had to take physics again. The majority will probably also never be interested in learning or using physics as a field itself later in their careers.

I realized that, for most people, the point of a physics general education class isn’t to learn physics. Physics classes are really a vehicle to teach mathematical thinking and reasoning skills to those who need it. Once I realized that physics wasn’t really the main point of the class, I was able to try to use the topics in physics to reinforce other very useful skills that the students would need later in their academic and professional careers. Most non-major physics courses should really be about teaching people qualitative reasoning skills that can be applied to nearly every other field of interest. I just wish that the students would have realized that as I believe they would have gotten considerably more out of the class that way.

If physics isn’t the point, then they really should be taking some sort of class in applied statistics. However, if they haven’t even mastered the basic skill of figuring out the slope of a line (isn’t that grade 9 math?), then what they really should be taking is a remedial math course so they have the appropriate prerequisites to succeed in other classes.

To need to teach slopes in a physics class is quite a surprise. The only other time I’ve heard of such things in university is in introductory courses in economics.

Why do students need to run to the library to plot data? Did they need to use the computer? I still remember plotting out data by hand on log-log paper back in my freshman days. It was quite satisfying.

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My son did slopes this year, in algebra. So yeah…8th or 9th grade.

Keep in mind that this was also an algebra-based course.

Honestly, I think that some of them learned it and forgot it because they really hadn’t used it. However, they were going to need to use it in the future, so I felt that I should really focus on that.

But I do think that a lot of people need to take physics not because of the fact that they need physics. Honestly, most people really don’t…but I do think that everyone would benefit from learning quantitative reasoning. I think physics is probably the best class that could ever do that because it shows how to approach a physical problem using math. I think the math folks forget the physical problem aspect, and most other sciences just don’t have the math to them.

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There’s a lot of math that science students (and science majors) should know when they get to college, but don’t. There’s math that could be in intro geology courses (and should be in upper level geology courses), but the students don’t come to college with the math skills, and some of the missing skills involve connecting the concrete science problems with the abstract reasoning used by mathematicians (which is what “mathematical reasoning” means to a lot of the math faculty I’ve talked to), and it’s not much fun to teach math in a geology class.

I’ve been helping pilot a program that’s trying to provide another tool to deal with the problem: The Math You Need (http://serc.carleton.edu/mathyouneed/index.html). It has online explanations and worked problems that deal with applying simple math to geologic problems. It’s not physics, but some of the modules might be useful for scientists outside geology. (There’s an explanation of slopes, for instance.)

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Personally I felt that the physics part in an intro physics course is more difficult than the math part (having never taken physics in high school). It’s like word problems you first see when you do algebra, arithmetics becomes secondary if you don’t know what the question asks for.

And in terms of math, I agree that a statistics course seems to be more appropriate, since people can find projects that would relate more to their major or interest, thus making math more relatable.

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