Noah S. Podolefsky

The Perceived Value of College Physics Textbooks: Students and Instructors May Not See Eye to Eye

This paper describes a study of student textbook use in four introductory college physics courses. Students were surveyed to find out how much they read their physics textbook, when they read, what effect (if any) this had on their performance, and if different instructors/textbooks made a difference. Survey results indicate that while over 97% of our students buy the required textbook, less than 41% regularly read, 60% read after lecture rather than before, and there is little (or no) correlation between reading habits and course grade. Further analysis of how and why students read indicates little or no variation in the perceived value of the textbook for course components tightly coupled to grades. We found that these results were strikingly similar across conceptual-, algebra-, and calculus-based courses with different instructors and textbooks.

Can Computer Simulations Replace Real Equipment in Undergraduate Laboratories

This paper examines the effects of substituting computer simulations in place of real laboratory equipment in the second semester of a large‐scale introductory physics course. The direct current (DC) circuit laboratory was modified to compare the effects of using computer simulations with the effects of using real light bulbs, meters and wires. Three groups of students, those who used real equipment, those who used computer simulations, and those who had no lab experience, were compared in terms of their mastery of physics concepts and skills with real equipment. Students who used the simulated equipment outperformed their counterparts both on a conceptual survey of the domain and in the coordinated tasks of assembling a real circuit and describing how it worked.

Affordances of play for student agency and student-centered pedagogy

While guided instruction can successfully focus students on concepts to be learned, this instructional approach can also reduce student agency and ownership of learning. Over the last two years, we have implemented PhET interactive computer simulations in middle school (MS) classrooms and found that “open play” can allow increased student agency and simultaneously lower barriers for student-centered pedagogy. In these MS classes, activities begin with 5-10 minutes of open play where students use the simulations without instruction. A moderately-guided, inquiry-based activity follows. In a study of classes with play versus no-play, we found that with play, the teacher focused on student ideas and science content, while without play the teacher employed more direct instruction.

Guiding without feeling guided: Implicit scaffolding through interactive simulation design

While PhET interactive simulations (sims) were historically designed for college students, they are used at lower grade levels, and we are currently developing sims targeted at middle school (MS). In studying how MS students interact with and learn from these sims, we have been extracting insights about design for the middle-grade-levels and across K-16. This collection of work has highlighted the importance of implicit scaffolding, a design framework that reduces the amount of explicit instruction needed to facilitate learning. We present a case study of redesigning a sim – Energy Skate Park (ESP) – for effective use in MS. We conducted think-aloud interviews with MS students to identify successful features, sources of confusion or unproductive distraction, as well as features inconsistent with gradeappropriate learning goals. Drawing on these data and the principle of implicit scaffolding, we developed Energy Skate Park Basics (ESPB). Interviews on ESPB demonstrate increased usability and learning for M...

Dispersion of capillary-gravity waves: a derivation based on conservation of energy

Waves on fluids provide an excellent context for introducing some important topics in fluid dynamics. In this paper we first discuss the behaviour of standing surface waves and present their special properties. Next the dispersion relation of surface waves is derived in a novel way by applying the conservation of energy to the case of standing waves.

Computer simulations to classrooms: tools for change

This paper situates PhET computer simulations (sims) in a socio‐cultural‐historical context. Sims are cultural tools designed to embody certain norms and practices of the physics community, particularly learning through exploration. We focus on interactions between three scales of tools: representations, materials, and environments. We examine critical features of tools across these three scales which support student learning through engaged exploration. We support our claims with data from studies of use of sims in introductory physics laboratories.

Salience of Representations and Analogies in Physics

This paper focuses on the dynamics as students reason using analogies. We describe analogical scaffolding, a model of cognitive processes by which students can use prior knowledge to learn new material, and apply this model to demonstrate its utility in describing the dynamics of student reasoning about EM waves in an interview. The present finegrained analysis confirms prior large‐scale findings, that representations play a key role in student use of analogy.

Capillary-gravity waves and the Navier-Stokes equation

Water waves are a source of great fascination for undergraduates and thus provide an excellent context for introducing some important topics in fluid dynamics. In this paper we introduce the potential theory for incompressible and inviscid flow and derive the differential equation that governs the behaviour of the velocity potential. Next we obtain the harmonic solutions of the velocity potential by a very general argument. These solutions in turn yield the equations for the velocity and displacement of a water element under the action of a harmonic wave. Finally we obtain the dispersion relation for surface waves by requiring that the harmonic solutions satisfy the Navier-Stokes equation.

How Abstract is Abstract? Layering meaning in physics.

External representations, including pictures, graphs, text, gestures, and utterances, are key components of all curricular materials in physics. Such representations play a key role in cognitive function, particularly insofar as individuals interpret the meanings of and apply meanings to these representations. We previously proposed a model of how individuals can make meaning of and with external representations through layered analogies and applied this model to learning abstract ideas in physics, i.e. EM waves. [1] [2] We extend this model in two ways. (1) We distinguish individuals’ interpretations of representations, which can be highly variable and fleeting, from the physics community’s agreed upon interpretations, which are more stable and coherent. (2) We describe these two dimensions of representation use: abstraction based on the community consensus of concepts and salience based on readily accessible pieces of knowledge for an individual.

Characterizing Complexity of Computer Simulations and Implications for Student Learning

Interactive simulations can be engaging tools for student learning, allowing students to explore phenomena by asking questions and seeking answers through use of the sim. PhET simulations allow this process to happen dynamically so that students can continuously probe and explore the underlying science. For students to use simulations productively, understanding the science in the simulation must be challenging enough to maintain students’ interest, but not so challenging that students are overwhelmed. A key aspect of achieving a good balance is the complexity of the simulation for students. We have formulated an initial model to quantify complexity based on the number, range, and effects of controls and representations within a simulation. We account for students’ prior knowledge by adjusting the measured complexity depending on how students interpret the representations and conceptual connections within the simulation. Implications for simulation design and student engagement will be discussed in light ...