Direct Measurement of the Impact of Teaching Experimentation in Physics Labs

While there have been many calls to improve the quality of instructional physics labs, there exists little research on the effectiveness of lab instruction. This study provides a direct comparison between labs that have goals to reinforce physics content to those that emphasize experimentation skills. In this controlled study, all students attended the same lecture and discussion sections, had the same homework and exams, but attended labs that had one of two aims: teaching experimentation or reinforcing content. We compare students’ engagement with experimentation during the lab as well as the impacts on students’ exam performance and attitudes and beliefs about experimental physics. We find no measurable differences between lab conditions on students’ exam performance. Nonetheless, we find measurable and significant improvements in students’ engagement in expertlike experimentation practices and attitudes and beliefs about experimental physics for students in the experimentation labs. The benefits of the experimentation labs are stable across two subsequent semesters of implementation, as measured via standardized assessments. The results provide direct evidence of the extensive benefits of using labs to teach experimentation while directly demonstrating that shifting instructional goals and structure in labs can occur without cost to performance on course exams.

Popular Summary

Despite many calls to improve the quality of physics-lab instruction, little research has been done to demonstrate the effectiveness of different goals and pedagogies. We aim to change that. In our investigation, we find direct evidence of the negative impacts of traditional labs and the compelling positive impacts of nontraditional labs on students’ attitudes and engagement in high-level experimentation skills, with no measurable differences in students’ exam performance.

Our controlled study compares the impact of traditional, highly structured labs that aim to reinforce physics concepts from lectures (“content-reinforcement labs”) with more open-ended, inquiry-based labs that aim to teach experimentation skills (“experimentation labs”). We compare students in the same lecture course in the same semester for a direct and isolated comparison of the impacts of lab instruction.

Despite concerns about content coverage, the type of lab does not measurably impact students’ exam scores, even though the labs have no intent to reinforce the content introduced in the rest of the course, and the number of concepts explored in the lab are cut in half. This “no harm” outcome goes hand in hand with improvements to students’ engagement with experimentation and their attitudes and perceptions of experimental physics, with consistent measurable benefits. The results also demonstrate that content-reinforcement labs may be causing measurable harm by deteriorating students’ attitudes and not engaging students with high-level scientific thinking.

This work lays the groundwork for replication studies and for physics educators to critically evaluate the roles and unique affordances of lab courses in physics education.

Figure 1

The fraction of groups in semesters 1 and 2 proposing and carrying out changes to their experiments (left, purple) and identifying and interpreting model disagreements (right, green) in their lab notes indicates that students extensively engage in these behaviors, with variation across activities and semesters. Lab activities (indicated on the $x$ axis) are ordered sequentially and correspond to weeks listed in Table 1.

Figure 2

Pairwise comparisons of exam scores by lab condition (left), major (center), and gender (right) for semester 1 show similar distributions between lab conditions, except on midterm II, but suggest different distributions between physics and nonphysics majors and between women and men on all exams. All exams are scored out of 100.

Figure 3

E-CLASS scores by lab condition (left), major (center), and gender (right). These results should be interpreted along with Table 5.

Figure 4

Model diagnostic plots using E-CLASS scores of students in semester 1.