What do students think about experimental physics?

Title: Students’ views about the nature of experimental physics
Authors: Bethany R. Wilcox and H. J. Lewandowski
First author’s institution: University of Colorado
Journal: Physical Review Physics Education Research 13, 020110 (2017)

While the discipline of physics consists of both theory and experiment, most physics education literature has tended to focus on theory and how students learn such theory. Equally important however, are the laboratory courses which typically provide instruction in experimental physics for students. Often, these lab courses try develop skills such as experimental design, data analysis, scientific communication, and modeling of experiments. Additionally, many lab courses hope to encourage students to develop physicist-like ideas about the nature and process of experimental physics, which is the focus of today’s paper. Specifically, the author’s of today’s paper are interested in characterizing the views of students in physics lab courses and seeing how they compare with the views of practicing experimental physicists. Additionally, the authors wanted to see how these views shift during the course of the class since previous research has found that students in introductory physics courses typically have views that are less aligned with physicist’s views at the end of the course than they had at the beginning.

To answer their results, the authors used a survey called the E-CLASS, which investigates students’ views about the nature and importance of experimental physics. The survey consists of 30 responses and the students respond to each prompt on a scale of “strongly disagree” to “strongly agree.” In addition, the student is supposed to predict how a practicing experimental physicist would respond to the same prompt. An example question is shown in figure 1.

Figure 1: Sample question on the E-CLASS. (Figure 1 in paper)

The researchers then collected responses from over 7,000 students from 130 courses at 75 different institutions. The courses were both first-year courses and more advanced courses which the authors refer to as beyond first-year courses. To analyze the data, the authors gave each student one point for each question if their response matched that of a practicing experimental physicists and no points otherwise. The same scheme was applied to the questions asking the students to predict the experimental physicist’s response. The experimental physicist’s response was formed through the consensus of 23 practicing experimental physicist’s responses to the same questions. Using this scoring scheme, the average score on the E-CLASS is the percent of statements where the student had the same view as an experimental physicist.

So what did the authors find? The authors found that before beginning their course, students in first-year courses responded the same way an experimental physicist would on roughly two-thirds of the questions while students in beyond first year courses responded the same way as an experimental physicist would on three-quarters of the questions. After completing their course, the students in first year courses responded the same way as an experimental physicist would to a slightly smaller fraction of the questions than they had at the beginning of the course. The students in beyond first year courses still responded in the same way as experimental physicists would on three-quarters of the questions. Thus, the researchers concluded that lab courses did not have a significant effect on the students’ views and in the same of the first-year classes, actually drove students to views that are less similar to those of experimental physicists.

Next, the authors wanted to see if there were any statements that most students in both first-year and non first-year courses answered significantly differently than the experimental physicists. They found four such statements:

  1.  If I am communicating my results from an experiment, my main goal is to have the correct sections and formatting.
  2. When I encounter difficulties in the lab, my first step is to ask an expert, like the instructor.
  3. When doing an experiment, I usually think up my own questions to investigate.
  4.  If I don’t have clear directions for analyzing data, I am not sure how to choose an appropriate analysis method.

For reference, an experimental physicist would agree with the third statement and disagree with the other three. Differing views on the first statement are likely due to grading practices in their courses while differing views on the other three statements are likely due to structure of the lab course. The authors note that differing views from experimental physicists on the latter three statements was not unexpected for students in first-year courses, but is unexpected and concerning for students in beyond first-year courses since working autonomously in a lab is an important skill for becoming a professional physicist, the assumed goal for students in an upper level physics lab course. Comparison of student and typical experimental physicist responses are shown in figure 2.

Figure 2: Fraction of students with the same view as a typical experimental physicist. Red corresponds to students in first year classes, while blue corresponds to students in beyond first year classes. Circles represent data from the beginning of the semester while arrows represent data from the end of the semester. Shaded region is a 95% confidence interval based on beginning of semester data. (Figure 2 in paper)

Finally, the authors wanted to compare the students’ predicted responses of experimental physicists to the typical response of an experimental physicist. They found that students in both first-year and beyond first-year courses correctly predicted the typical experimental physicist’s response over 80% of the time. Only one item was correctly predicted by students from both class types less than 50% of the time: ” If I am communicating my results from an experiment, my main goal is to have the correct sections and formatting.” The authors note that an experimental physicist would disagree with this statement, but style and structure guidelines are still very important for publications and funding applications.

So why do these results matter? First, the results suggest that lab courses are not effective in helping students to develop views about the nature of experimental physics that are consistent with how physicists view experimental physics. Nevertheless, students are fairly good at predicting the views of experimental physicists, even if the student doesn’t have the same viewpoint. Second, since the individual lab courses are not effective in helping students to develop “experimental-physicist like” views, any attempt to achieve improvements will likely require changes in a physics department’s curriculum as a whole rather than in a few individual courses as is typical for introducing physics education research inspired reforms.

Figures used under Creative Commons Attribution 4.0 License.


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