Gauging What Students Understand -- In Class, at American Association of Physics Teachers Winter Meeting (New Orleans, LA), Monday, January 5, 1998
Promoting Innovations in Learning: PBL, TBL, and Learning Catalytics, at Center for Promotion of Excellence in Higher Education Workshop, Kyoto University (Kyoto, Japan), Thursday, October 10, 2013:
How the mind tricks us: visualizations and visual illusions, at Gordon Conference on Visualization in Science and Education, Queens College, Oxford University (Oxford, UK), Tuesday, July 22, 2003:
Flat space, deep learning, at Team-Based Learning Collaborative Annual Conference (St. Petersburg, FL), Thursday, March 6, 2014
Qualitative versus quantitative reasoning: Are we teaching the right thing?” In Motivating Science: Science communication from a philosophical, educational and cultural perspective, , Pp. 139–141. The Panteneto Press. Publisher's VersionAbstract. 2005. “
This paper is a reprinting of an article that first appeared in Optics and Photonics News in 1992. The article deals with the eye-opening experience that made me completely change my approach to teaching.
Interpreting Assessments of Student Learning in the Introductory Physics Classroom and Laboratory”. Publisher's VersionAbstract. 2012. “
Assessment is the primary means of feedback between students and instructors. However, to effectively use assessment, the ability to interpret collected information is essential. We present insights into three unique, important avenues of assessment in the physics classroom and laboratory. First, we examine students’ performance on conceptual surveys. The goal of this research project is to better utilize the information collected by instructors when they administer the Force Concept Inventory (FCI) to students as a pre-test and post-test of their conceptual understanding of Newtonian mechanics. We find that ambiguities in the use of the normalized gain, g, may influence comparisons among individual classes. Therefore, we propose using stratagrams, graphical summaries of the fraction of students who exhibit “Newtonian thinking,” as a clearer, more informative method of both assessing a single class and comparing performance among classes. Next, we examine students’ expressions of confusion when they initially encounter new material. The goal of this research project is to better understand what such confusion actually conveys to instructors about students’ performance and engagement. We investigate the relationship between students’ self-assessment of their confusion over material and their performance, confidence in reasoning, pre-course self-efficacy and several other measurable characteristics of engagement. We find that students’ expressions of confusion are negatively related to initial performance, confidence and self-efficacy, but positively related to final performance when all factors are considered together. Finally, we examine students’ exhibition of scientific reasoning abilities in the instructional laboratory. The goal of this research project is to explore two inquiry- based curricula, each of which proposes a different degree of scaffolding. Students engage in sequences of these laboratory activities during one semester of an introductory physics course. We find that students who participate in the less scaffolded activities exhibit marginally stronger scientific reasoning abilities in distinct exercises throughout the semester, but exhibit no differences in the final, common exercises. Overall, we find that, although students demonstrate some enhanced scientific reasoning skills, they fail to exhibit or retain even some of the most strongly emphasized skills.
Losing it: The Influence of Losses on Individuals' Normalized Gains.” In . PERC. Publisher's VersionAbstract. 2010. “
Researchers and practitioners routinely use the normalized gain (Hake, 1998) to evaluate the effectiveness of instruction. Normalized gain (g) has been useful in distinguishing active engagement from traditional instruction. Recently, concerns were raised about normalized gain because it implicitly neglects retention (or, equivalently, "losses"). That is to say, g assumes no right answers become wrong after instruction. We analyze individual standardized gain (G) and loss (L) in data collected at Harvard University during the first five years that Peer Instruction was developed. We find that losses are non-zero, and that losses are larger among students with lower pre-test performances. These preliminary results warrant further research, particularly with different student populations, to establish whether the failure to address loss changes the conclusions drawn from g.
Teaching and physics education research: bridging the gap.” Reports on Progress in Physics, 77, Pp. 032401–032417. Publisher's VersionAbstract. 2014. “
Physics faculty, experts in evidence-based research, often rely on anecdotal experience to guide their teaching practices. Adoption of research-based instructional strategies is surprisingly low, despite the large body of physics education research (PER) and strong dissemination effort of PER researchers and innovators. Evidence-based PER has validated specific non-traditional teaching practices, but many faculty raise valuable concerns toward their applicability. We address these concerns and identify future studies required to overcome the gap between research and practice.
Simultaneous Observation of Molecular Tilt and Azimuthal Angle Distributions in Spontaneously Modulated Liquid-Crystalline Langmuir Monolayers.” Phys. Rev. Lett., 82, Pp. 759–762. Publisher's VersionAbstract. 1999. “
We carried out the first quantitative measurements of correlated modulations of molecular tilt and azimuthal angles in two-dimensional (2D) smectic C Langmuir monolayers using simultaneous linear- and circular-polarized reflected light microscopy. For spontaneously formed stripes and higher-order point defects, the tilt angle varies nearly sinusoidally at twice the spatial frequency of the azimuthal rotation. The tilt modulation grows as the second power of the modulation wavenumber and leads to a large escaped core for the point defect. Our results can be explained by an extended Landau theory of tilted smectics.
Two steps forward, one step back.” Nature Physics, 10, Pp. 402–403. Publisher's VersionAbstract. 2014. “
Among physics students there exists a wide variety of misconceptions, generally thought to be robust and resistant to change. But our analysis of the path of progress has changed our conception of how students learn physics.
Examining issues of underrepresented minority students in introductory physics”. Publisher's VersionAbstract. 2010. “
In this dissertation we examine several issues related to the retention of underrepresented minority students in physics and science. In the first section, we show that in calculus-based introductory physics courses, the gender gap on the FCI is diminished through the use of interactive techniques, but in lower-level introductory courses, the gap persists, similar to reports published at other institutions. We find that under-represented racial minorities perform similar to their peers with comparable academic preparation on conceptual surveys, but their average exam grades and course grades are lower. We also examine student persistence in science majors; finding a significant relationship between pedagogy in an introductory physics course and persistence in science. In the second section, we look at student end-of-semester evaluations and find that female students rate interactive teaching methods a full point lower than their male peers. Looking more deeply at student interview data, we find that female students report more social issues related to the discussions in class and both male and female students cite feeling pressure to obtain the correct answer to clicker questions. Finally, we take a look an often-cited claim for gender differences in STEM participation: cognitive differences explain achievement differences in physics. We examine specifically the role of mental rotations in physics achievement and problem-solving, viewing mental rotations as a tool that students can use on physics problems. We first look at student survey results for lower-level introductory students, finding a low, but significant correlation between performance on a mental rotations test and performance in introductory physics courses. In contrast, we did not find a significant relationship for students in the upper-level introductory course. We also examine student problem-solving interviews to investigate the role of mental rotations on introductory problems.
Qualitative versus quantitative reasoning: Are we teaching the right thing?” Optics and Photonics News. Publisher's VersionAbstract. 1992. “
For the past eight years I have been teaching an introductory physics course for engineering and science concentrators at Harvard University. Teaching this class, which does not include any physics majors, is a challenging experience because the students take this course as a concentration requirement, not because of a genuine interest in physics. At the same time it can be a very rewarding experience when, at the end of the semester, students show much more appreciation for the subject matter. I used to teach a fairly traditional course in an equally traditional lecture-type of presentation, enlivened by classroom demonstrations. I was generally satisfied with my teaching during these years my students did well on what I considered pretty difficult problems and the feedback I received from them was positive. About a year ago, however, I came across a series of articles by David Hestenes of Arizona State University, which completely and permanently changed my views on teaching.
Principles & Practice of Physics, Pp. 1275. Pearson. Publisher's VersionAbstract. 2014.
The Principles and Practice of Physics is a new calculus-based introductory physics textbook that uses a unique organization and pedagogy to allow students to develop a true conceptual understanding of physics alongside the quantitative skills needed in the course. The book organizes introductory physics around the conservation principles and provides a unified contemporary view of introductory physics. The result of this reorganization is a groundbreaking new book that puts principles first, thereby making it more accessible to students and easier for instructors to teach. To request an examination copy of the complete book, please visit the book web site ISBN-13: 9780136150930
Assessing and Enhancing the Introductory Science Course in Physics and Biology: Peer Instruction, Classroom Demonstrations, and Genetics Vocabulary”. Publisher's VersionAbstract. 2003. “
Most introductory college science courses in the United States are taught in large lectures with students rarely having the opportunity to think critically about the material being presented nor to participate actively. Further, many classes focus on teaching rather than learning, that is, the transfer of information as opposed to actual student understanding. This thesis focuses on three studies about the assessment and enhancement of learning in undergraduate science courses. We describe the results of an international survey on the implementation of Peer Instruction (PI), a collaborative learning pedagogy in which lectures are interspersed with short conceptual questions designed to challenge students to think about the material as it is being presented. We present a portrait of the many instructors teaching with PI and the settings in which it is being used as well as data on the effectiveness of PI in enhancing student learning in diverse settings. The wide variety of implementations suggests that PI is a highly adaptable strategy that can work successfully in almost any environment. We also provide recommendations for those considering adopting PI in their classes. Classroom demonstrations are an important aspect of many introductory science courses, but there is little evidence supporting their educational effectiveness. We explore the effect of different modes of presentation on enhancing student learning from demonstrations. Our results show that students who actively engage with a demonstration by predicting the outcome before it is conducted are better able to recall and explain the scenario posed by that demonstration. As preliminary work for the creation of an inventory of conceptual understanding in introductory biology, we discuss results from a survey of vocabulary familiarity and understanding in an undergraduate genetics course. Students begin introductory classes with significant gaps in their understanding, some of which are retained beyond instruction. Further, they overstate their knowledge, and the degree to which they exhibit overconfidence increases over the period of instruction.
Testing the test: Item response curves and test quality.” Am. J. Phys., 74, Pp. 449–453. Publisher's VersionAbstract. 2005. “
We present a simple technique for evaluating multiple-choice questions and their answer choices beyond the usual measures of difficulty and the effectiveness of distractors. The technique involves the construction and qualitative consideration of item response curves (IRCs) and is based upon Item Response Theory from the field of education measurement. Item response curves relate the percentage of students who select each possible answer choice to overall ability level. To demonstrate the technique, we apply IRC analysis to three questions from the Force Concept Inventory (FCI). IRC analysis allows us to characterize qualitatively whether these questions are efficient, where efficient is defined in terms of the construction, performance, and discrimination of a question and its answer choices. Such analysis can be useful both in the development of future multiple-choice examination questions and in the development of a better understanding of results from existing diagnostic instruments such as the FCI.