Catálogo de publicaciones - revistas

<jats:p>We describe a dual-class authentic learning experience (ALE) in which undergraduate upper-division physics students develop low-cost instruments, which are then used by students in a lower-division course to monitor water quality in rivers. The ALE bridges the experiences of lower- and upper-division physics majors by involving students across different stages of their college careers in a collaborative project. Lower-division physics students characterize, calibrate, and troubleshoot the instrument prototypes developed by their upper-division peers, and their work informs instrument modifications in future upper-division physics classes. This paper describes the first iteration of this project along with student perceptions. We find that lower-division students report an increase in their awareness of possible upper-division projects, an increased sense that their coursework has real-world applications, and a heightened understanding of how physicists can play a role in research on environmental issues.</jats:p>

<jats:p>Climate change issues have become far more complex and better studied over the last few years. Making sense of how the causes and effects of climate change create a coherent framework can empower learners to engage in productive discourse and to ask deeper questions. Historical contexts, current approaches to mitigate climate change, and future demands are all a part of the ongoing research and efforts. This global, social justice issue will only become more pressing, and we need to support students in making informed decisions about their actions going forward. It is for this reason that we (a physics instructor and an energy consultant) have joined together to create a list of topics that all students should consider as they move through our educational programs.</jats:p>

<jats:p>We present an experiment investigating the physics of the atmospheric greenhouse effect that can be performed by undergraduate physics students. The students construct a three-channel spectral photometer to observe the infrared heat flux in the atmosphere. With this spectral photometer, the students observe the difference in heat flux between the portion of the IR spectrum that is absorbed by water vapor and carbon dioxide and the portion that is not absorbed by atmospheric constituents. The students discover that Earth's surface is warmed by radiation from the greenhouse gas absorption bands, and the radiation of heat to space is retarded by the absorption bands. One component of the experiment is performed on the ground and the other component is performed in the atmosphere using a high-altitude balloon. The students then compare their results to a simulation of infrared radiation transport in the atmosphere.</jats:p>

<jats:p>Footprints provide a way to estimate the relative impact of processes and products on the global climate. Including footprint analysis in a course on energy simultaneously provides students with an understanding of this tool and a quantitative guide to approaches that address climate change. College-level classroom activities for (primarily) process-based life cycle carbon footprinting are discussed.</jats:p>

<jats:p>I present a discussion of the effect of increasing carbon dioxide on planetary climate, at a level suitable for insertion as a module into an upper-level Physics course. The treatment includes two key ingredients that are often missing from more elementary discussions, yet are amenable to analytic methods: First, that convection implies a dependence of surface temperature on the height of the outermost infrared-thick layer; and second, that increasing the level of CO2 closes spectral windows of absorption. These themes are applicable not only to an industrializing Earth but also to our neighboring planets.</jats:p>

<jats:p>Simple models for Earth's climate sensitivity (i.e. its temperature response to radiative forcing) are developed by combining the time-tested idealization of one-dimensional radiative-convective equilibrium (RCE) with simple yet quantitatively reasonable models for CO2 forcing and the water vapor feedback. Along the way, we introduce key paradigms including the emission level approximation, the forcing-feedback decomposition of climate sensitivity, and “Simpson's law” for water vapor thermal emission. We also discuss climate feedbacks unaccounted for in this RCE framework, as well as differing variants of climate sensitivity, all of which may be ripe for their own chalkboard treatments.</jats:p>

<jats:p>The ability to track flows of energy in complex and dissipative contexts is essential to understand many aspects of sustainable energy and climate change. Traditional physics instruction largely fails to develop that ability. This work argues that one plausible contributor to this deficiency could be an overemphasis on cases that lend themselves to quantitative calculation. Drawing on examples and data from a small sample of college physics students in a class on sustainable energy, it proposes that practice in semiquantitative energy tracking, using suitable visual and/or manipulable representations, can help develop students' skills in using energy reasoning in real-world, dissipative contexts.</jats:p>