Assessing the impact of introductory physics for the life sciences on students’ ability to build complex models

A central goal of introductory physics for the life sciences (IPLS) is to prepare students to use physics to model and analyze biological situations, a skill of increasing importance for their future studies and careers. Here we report our findings on life science students’ ability to carry out a sophisticated biological modeling task at the end of first-semester introductory physics. Some students were enrolled in a standard course ($N=34$), and some in an IPLS course ($N=61$); both courses were taught with active learning, used calculus, and included the same core physics concepts. Compared to those who took the standard course, we found that the IPLS students were significantly more successful at building a model that combined ideas in a manner they had not previously seen, and at making complex decisions about how to apply an equation to a particular physical situation, although both groups displayed similar success at solving simpler problems. Both groups identified and applied simple models that they had previously used in very similar contexts, and executed straightforward calculations, at statistically indistinguishable rates. We report both our findings and the rationale behind the development of the task, in the hopes that others may find this task either a valuable tool or a starting point to develop other such tasks. Further study is needed to determine the basis for the IPLS students’ stronger performance—namely, what aspects of the IPLS course support these students to be better prepared to do such modeling—as well as whether biological settings are important for IPLS students to succeed in flexible model building, and whether the ability to employ models flexibly persists over time.

Figure 1

Part (a) of the fluids problem. Photo from Wikimedia Commons, Miroslav Ducacheck, CC BY-SA 3.0. The full task (including instructions preceding the fluids problem, the thermodynamics problem, and the list of equations) is provided in the Supplemental Material [25].

Figure 2

Part (b) of the fluids problem. The full task is provided in the Supplemental Material [25].

Figure 3

Part (c) of the fluids problem. The full task is provided in the Supplemental Material [25].

Figure 4

Rubric scores for problems requiring implementing a model that had been previously used in class, from non-IPLS students (blue envelope around black dots) and IPLS students (green envelope around black dots): (a) part (a) of the fluids task (code in Table 1), (b) parts (a) and (b) of the thermodynamics task (code in the Appendix). Each student’s score is represented by a black dot, and the median score is represented by a yellow dot; “ns” stands for not significant and means $p>0.05$. Bayesian odds ratios in favor of the null hypothesis were (a) 2.8 and (b) 2.3.

Figure 5

Total calculation rubric scores for non-IPLS students (blue envelope around black dots) and IPLS students (green envelope around black dots). Each student’s score is represented by a black dot, and the median score is represented by a yellow dot; “ns” (not significant) means $p>0.05$.

Figure 6

(a),(b) Rubric scores on part (b) of the fluids task from non-IPLS students (blue envelope around black dots) and IPLS students (green envelope around black dots): (a) total score over all rubric elements, (b) score for justification and coordinating models. (c) For comparison, scores on part (c) of the thermodynamics task, which required some modeling as discussed in the text. One non-IPLS student skipped part (b) of the fluids task and completed the other parts, hence different $N$ values. Each student’s score is represented by a black dot, and the median score is represented by a yellow dot; “ns” stands for not significant and means $p>0.05$; **** indicates $p<0.0001$.

Figure 7

Overall rubric scores for coordinating equations to physical situations from non-IPLS students (blue envelope, black dots) and IPLS students (green envelope, black dots) from parts (a) and (b) of the fluids task. Each student’s score is represented by a black dot, and the median score is represented by a yellow dot. *** indicates $p<0.001$.