No Arabic abstract
A goal of Introductory Physics for Life Sciences (IPLS) curricula is to prepare students to effectively use physical models and quantitative reasoning in biological and medical settings. To assess whether this goal is being met, we conducted a longitudinal study of the impact of IPLS on student work in later biology and chemistry courses. We report here on one part of that study, a comparison of written responses by students with different physics backgrounds on a diffusion task administered in a senior biology capstone course. We observed differences in student reasoning that were associated with prior or concurrent enrollment in IPLS. In particular, we found that IPLS students were more likely than non-IPLS students to reason quantitatively and mechanistically about diffusive phenomena, and to successfully coordinate between multiple representations of diffusive processes, even up to two years after taking the IPLS course. Finally, we describe methodological challenges encountered in both this task and other tasks used in our longitudinal study.
Energy is a complex idea that cuts across scientific disciplines. For life science students, an approach to energy that incorporates chemical bonds and chemical reactions is better equipped to meet the needs of life sciences students than a traditional introductory physics approach that focuses primarily on mechanical energy. We present a curricular sequence, or thread, designed to build up students understanding of chemical energy in an introductory physics course for the life sciences. This thread is designed to connect ideas about energy from physics, biology, and chemistry. We describe the kinds of connections among energetic concepts that we intended to develop to build interdisciplinary coherence, and present some examples of curriculum materials and student data that illustrate our approach.
In an Introductory Physics for Life Science (IPLS) course that leverages authentic biological examples, student ideas about entropy as disorder or chaos come into contact with their ideas about the spontaneous formation of organized biological structure. It is possible to reconcile the natural tendency to disorder with the organized clustering of macromolecules, but doing so in a way that will be meaningful to students requires that we take seriously the ideas about entropy and spontaneity that students bring to IPLS courses from their prior experiences in biology and chemistry. We draw on case study interviews to argue that an approach that emphasizes the interplay of energy and entropy in determining spontaneity (one that involves a central role for free energy) is one that draws on students resources from biology and chemistry in particularly effective ways. We see the positioning of entropic arguments alongside energetic arguments in the determination of spontaneity as an important step toward making our life science students biology, chemistry, and physics experiences more coherent.
An important goal of introductory physics for the life sciences (IPLS) is for those students to be prepared to use physics to model and analyze biological situations in 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 in a standard course (N = 34), and some in an IPLS course (N = 61), both taught with active learning and covering the same core physics concepts. We found that the IPLS students were dramatically more successful at building a model combining multiple ideas they had not previously seen combined, 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 calculations, at statistically indistinguishable rates. Further study is needed to determine whether IPLS students are more expert problem-solvers in general or solely in biological settings.
Laboratory courses are key components of most undergraduate physics programs. Lab courses often aim to achieve the following learning outcomes: developing students experimental skills, engaging students in authentic scientific practices, reinforcing concepts, and inspiring students interest and engagement in physics. Some of these outcomes can be measured by the Colorado Learning Attitudes about Science Survey for Experimental Physics (E-CLASS), a research-based assessment that measures students views about experimental physics. We used E-CLASS at the University of Colorado Boulder to measure learning outcomes during a course transformation process in which views about experimental physics were reflected in the learning goals. We collected over 600 student responses per semester from the large introductory laboratory course, both before and after implementing the course transformation. While we observed no statistically significant difference in overall post-instruction E-CLASS scores before and after the transformation, in the transformed course, student responses to three E-CLASS items that related to the goals of the transformation were more favorable than in the original course.
Mathematical reasoning skills are a desired outcome of many introductory physics courses, particularly calculus-based physics courses. Positive and negative quantities are ubiquitous in physics, and the sign carries important and varied meanings. Novices can struggle to understand the many roles signed numbers play in physics contexts, and recent evidence shows that unresolved struggle can carry over to subsequent physics courses. The mathematics education research literature documents the cognitive challenge of conceptualizing negative numbers as mathematical objects--both for experts, historically, and for novices as they learn. We contribute to the small but growing body of research in physics contexts that examines student reasoning about signed quantities and reasoning about the use and interpretation of signs in mathematical models. In this paper we present a framework for categorizing various meanings and interpretations of the negative sign in physics contexts, inspired by established work in algebra contexts from the mathematics education research community. Such a framework can support innovation that can catalyze deeper mathematical conceptualizations of signed quantities in the introductory courses and beyond.