Michael Dubson

PhET: Interactive Simulations for Teaching and Learning Physics

The Physics Education Technology (PhET) project creates useful simulations for teaching and learning physics and makes them freely available from the PhET website (http://phet.colorado.edu). The simulations (sims) are animated, interactive, and game-like environments in which students learn through exploration. In these sims, we emphasize the connections between real-life phenomena and the underlying science, and seek to make the visual and conceptual models of expert physicists accessible to students. We use a research-based approach in our design—incorporating findings from prior research and our own testing to create sims that support student engagement with and understanding of physics concepts.The Physics Education Technology (PhET) project creates useful simulations for teaching and learning physics and makes them freely available from the PhET website (http://phet.colorado.edu). The simulations (sims) are animated, interactive, and game-like environments in which students learn through exploration. In these sims, we emphasize the connections between real-life phenomena and the underlying science, and seek to make the visual and conceptual models of expert physicists accessible to students. We use a research-based approach in our design—incorporating findings from prior research and our own testing to create sims that support student engagement with and understanding of physics concepts.

Developing and researching PhET simulations for teaching quantum mechanics

Quantum mechanics is counterintuitive, difficult to visualize, mathematically challenging, and abstract. The Physics Education Technology (PhET) Project now includes 18 simulations on quantum mechanics designed to improve the learning of this subject. These simulations include several key features to help students build mental models and intuition about quantum mechanics: visual representations of abstract concepts and microscopic processes that cannot be directly observed, interactive environments that directly couple students’ actions to animations, connections to everyday life, and efficient calculations so that students can focus on the concepts rather than the mathematics. Like all PhET simulations, these are developed using the results of research and feedback from educators, and are tested in student interviews and classroom studies. This article provides an overview of the PhET quantum simulations and their development. We also describe research demonstrating their effectiveness and discuss some i...

Island‐to‐percolation transition during growth of metal films

Metal films grown on nonwetting substrates evolve from an early stage of isolated compact islands to a later stage of elongated islands and percolation. Results are presented of a scanning electron microscopy study of Pb on SiO2 showing that the critical island radius Rc at which this crossover occurs is strongly dependent on temperature and weakly dependent on deposition rate. The experimental results are semiquantitatively described by a kinetic freezing model, in which the rate of island coalescence due to surface diffusion competes with the rate of island growth due to deposition.

Research‐based Practices For Effective Clicker Use

Adoption of clickers by faculty has spread campus‐wide at the University of Colorado at Boulder from one introductory physics course in 2001 to 19 departments, 80 courses, and over 10,000 students. We study common pedagogical practices among faculty and attitudes and beliefs among student clicker‐users across campus. We report data from online surveys given to both faculty and students in the Spring 2007 semester. Additionally, we report on correlations between student perceptions of clicker use and the ways in which this educational tool is used by faculty. These data suggest practices for effective clicker use that can serve as a guide for faculty who integrate this educational tool into their courses.

The Design and Validation of the Colorado Learning Attitudes about Science Survey

The Colorado Learning Attitudes about Science Survey (CLASS) is a new instrument designed to measure various facets of student attitudes and beliefs about learning physics. This instrument extends previous work by probing additional facets of student attitudes and beliefs. It has been written to be suitably worded for students in a variety of different courses. This paper introduces the CLASS and its design and validation studies, which include analyzing results from over 2400 students, interviews and factor analyses. Methodology used to determine categories and how to analyze the robustness of categories for probing various facets of student learning are also described. This paper serves as the foundation for the results and conclusions from the analysis of our survey data.

Atomically flat gold films grown on hot glass

The results of a scanning tunneling microscope (STM) study of the morphology of Au films thermally evaporated onto heated glass substrates are presented. Au films of thickness 20–80 nm were evaporated onto Corning glass cover slips at temperatures of 20–465 °C. Before the evaporation, the glass substrates were prebaked at 300–400 °C for 12 h to remove surface contamination. Grain size and surface roughness of the films have been measured, and the best results were obtained with Au films 80 nm thick evaporated onto 300 °C substrates. These films have 250‐nm‐diam grains with large, atomically flat tops exhibiting step‐free terraces as large as 200×200 nm2. These results are comparable to the best reported results for Au grown on heated mica and show that epitaxial growth is not required for the production of films with large atomically flat regions. This study of Au on glass was motivated by failed attempts to produce flat films of gold on mica using recipes in the literature. Possible reasons for the poor ...

Transforming Upper‐Division Quantum Mechanics: Learning Goals and Assessment

In order to help students overcome documented difficulties learning quantum mechanics (QM) concepts, we have transformed our upper‐division QM I course using principles of learning theory and active engagement. Key components of this process include establishing learning goals and developing a valid, reliable conceptual assessment tool to measure the extent to which students achieve these learning goals. The course learning goals were developed with broad faculty input, and serve as the basis for the design of the course assessment tool. The development of the assessment tool has included significant faculty input and feedback, twenty‐one student interviews, a review of PER literature, and administration of the survey to two semesters of QM I students as well as to a cohort of graduate students. Here, we discuss this ongoing development process and present initial findings from our QM class for the past two semesters.

Simple, variable‐temperature, scanning tunneling microscope

We describe a simple scanning tunneling microscope (STM) which works well from room temperature to 4 K. It is relatively easy to build, repair, or modify, and works very reliably. An unusual feature of our STM is that it is assembled without glues or solders. A list of suppliers of the components used in our STM is included in the references.

The use of concept tests and peer instruction in upper‐division physics

Many upper‐division courses at the University of Colorado now regularly use peer instruction in the form of clicker questions during lectures. Particular attention has been paid to developing and implementing clicker questions in junior‐level E&M and Quantum mechanics. These transformed classes largely follow traditional local norms of syllabus and content coverage, but are designed to address broader learning goals (e.g developing math‐physics connections) that our faculty expect from physics majors in these courses. Concept‐tests are designed to align with these goals, and have altered the dynamic of our classes. Coupled with other course transformations, we find measurable improvement in student performance on targeted conceptual post‐tests. Here, we discuss classroom logistics of upper‐division clickers, purposes of clicker questions, aspects of student engagement facilitated by concept‐tests, and observations of and challenges to sustainability of this activity.

Faculty Disagreement about the Teaching of Quantum Mechanics

To guide research‐based transformation of upper‐division physics classes, it is useful to identify learning goals that are broadly supported by the faculty. Our efforts to transform our junior‐level EM (2) the treatment of measurement in QM (in particular, the collapse of the wave function); and (3) the physical interpretation of the wave function (matter wave vs. information wave vs. something else).