David E. Meltzer

The relationship between mathematics preparation and conceptual learning gains in physics: A possible “hidden variable” in diagnostic pretest scores

There have been many investigations into the factors that underlie variations in individual student performance in college physics courses. Numerous studies report a positive correlation between students’ mathematical skills and their exam grades in college physics. However, few studies have examined students’ learning gain resulting from physics instruction, particularly with regard to qualitative, conceptual understanding. We report on the results of our investigation into some of the factors, including mathematical skill, that might be associated with variations in students’ ability to achieve conceptual learning gains in a physics course that employs interactive-engagement methods. It was found that students’ normalized learning gains are not significantly correlated with their pretest scores on a physics concept test. In contrast, in three of the four sample populations studied it was found that there is a significant correlation between normalized learning gain and students’ preinstruction mathematics skill. In two of the samples, both males and females independently exhibited the correlation between learning gain and mathematics skill. These results suggest that students’ initial level of physics concept knowledge might be largely unrelated to their ability to make learning gains in an interactive-engagement course; students’ preinstruction algebra skills might be associated with their facility at acquiring physics conceptual knowledge in such a course; and between-class differences in normalized learning gain may reflect not only differences in instructional method, but student population differences (“hidden variables”) as well.

Transforming the lecture-hall environment: The fully interactive physics lecture

Numerous reports suggest that learning gains in introductory university physics courses may be increased by “active-learning” instructional methods. These methods engender greater mental engagement and more extensive student–student and student–instructor interaction than does a typical lecture class. It is particularly challenging to transfer these methodologies to the large-enrollment lecture hall. We report on seven years of development and testing of a variant of Peer Instruction as pioneered by Mazur that aims at achieving virtually continuous instructor–student interaction through a “fully interactive” physics lecture. This method is most clearly distinguished by instructor–student dialogues that closely resemble one-on-one instruction. We present and analyze a detailed example of such classroom dialogues, and describe the format, procedures, and curricular materials required for creating the desired lecture-room environment. We also discuss a variety of assessment data that indicate strong gains in...

Relation between students’ problem-solving performance and representational format

An analysis is presented of data on students’ problem-solving performance on similar problems posed in diverse representations. Five years of classroom data on 400 students collected in a second-semester algebra-based general physics course are presented. Two very similar Newton’s third-law questions, one posed in a verbal representation and one in a diagrammatic representation using vector diagrams, were given to students at the beginning of the course. The proportion of correct responses on the verbal question was consistently higher than on the diagrammatic question, and the pattern of incorrect responses on the two questions also differed consistently. Two additional four-question quizzes were given to students during the semester; each quiz had four very similar questions posed in the four representations: verbal, diagrammatic, mathematical/symbolic, and graphical. In general, the error rates for the four representations were very similar, but there was substantial evidence that females had a slightly higher error rate on the graphical questions relative to the other representations, whereas the evidence for male students was more ambiguous. There also was evidence that females had higher error rates on circuit-diagram problems in comparison with males, although both males and females had received identical instruction .

Investigation of students’ reasoning regarding heat, work, and the first law of thermodynamics in an introductory calculus-based general physics course

Students in an introductory university physics course were found to share many substantial difficulties related to learning fundamental topics in thermal physics. Responses to written questions by 653 students in three separate courses were consistent with the results of detailed individual interviews with 32 students in a fourth course. Although most students seemed to acquire a reasonable grasp of the state-function concept, it was found that there was a widespread and persistent tendency to improperly over-generalize this concept to apply to both work and heat. A large majority of interviewed students thought that net work done or net heat absorbed by a system undergoing a cyclic process must be zero, and only 20% or fewer were able to make effective use of the first law of thermodynamics even after instruction. Students’ difficulties seemed to stem in part from the fact that heat, work, and internal energy share the same units. The results were consistent with those of previously published studies of students in the U.S. and Europe, but portray a pervasiveness of confusion regarding process-dependent quantities that has been previously unreported. Significant enhancements of current standard instruction may be required for students to master basic thermodynamic concepts.

Resource Letter ALIP–1: Active-Learning Instruction in Physics

This Resource Letter provides a guide to the literature on research-based active-learning instruction in physics. These are instructional methods that are based on, assessed by, and validated through research on the teaching and learning of physics. They involve students in their own learning more deeply and more intensely than does traditional instruction, particularly during class time. The instructional methods and supporting body of research reviewed here offer potential for significantly improved learning in comparison to traditional lecture-based methods of college and university physics instruction. We begin with an introduction to the history of active learning in physics in the United States, and then discuss some methods for and outcomes of assessing pedagogical effectiveness. We enumerate and describe common characteristics of successful active-learning instructional strategies in physics. We then discuss a range of methods for introducing active-learning instruction in physics and provide references to those methods for which there is published documentation of student learning gains.

Initial understanding of vector concepts among students in introductory physics courses

We report the results of an investigation into physics students’ understanding of vector addition, magnitude, and direction for problems presented in graphical form. A seven-item quiz, including free-response problems, was administered in all introductory general physics courses during the 2000/2001 academic year at Iowa State. Responses were obtained from 2031 students during the first week of class. We found that more than one quarter of students beginning their second semester of study in the calculus-based physics course, and more than half of those beginning the second semester of the algebra-based sequence, were unable to carry out two-dimensional vector addition. Although the total scores on the seven-item quiz were somewhat better for students in their second semester of physics in comparison to students in their first semester, many students retained significant conceptual difficulties regarding vector methods that are heavily employed throughout the physics curriculum.

Age dependence of Olympic weightlifting ability

There is increasing interest among Masters athletes in standards for comparing performances of competitors of different ages. The goal of this study was to develop one such age-comparison method by examining the age dependence of ability in Olympic-style weightlifting. Previous research on the deterioration of muscular strength and power with increasing age offers only limited guidance toward this goal; therefore, analysis of performance data was required. The variation of weightlifting ability as a function of age was examined by two different methods. First, cross-sectional data corresponding to two separate populations of Masters weightlifters were analyzed in detail. Then, a longitudinal study of 64 U.S. male Masters weightlifters was carried out, with performance versus age curves resulting from the two methods were very similar, reflecting approximately 1.0-1.5% x yr-1 deterioration rates. These curves were characterized by common features regarding the rate of decline of muscular power with increasing age, in apparent agreement with published data regarding Masters sprinters and jumpers. We tentatively conclude that Olympic weightlifting ability in trained subjects undergoes a nonlinear decline with age, in which the second derivative of the performance versus age curve repeatedly changes sign.

Student learning of thermochemical concepts in the context of solution calorimetry

Student understanding of heat and thermal phenomena has been the subject of considerable investigation in the science education literature. Published studies have reported student conceptions on a variety of advanced topics, but calorimetry - one of the more elementary applications of thermochemical concepts - has apparently received little attention from science education researchers. Here we report a detailed analysis of student performance on solution calorimetry problems in an introductory university chemistry class. We include data both from written classroom exams for 207 students, and from an extensive longitudinal interview series with a single subject who was herself part of that larger class. Our findings reveal a number of learning difficulties, most of which appear to originate from failure to understand that net increases and decreases in bond energies during aqueous chemical reactions result in energy transfers out of and into, respectively, the total mass of the resultant solution.

Student ideas regarding entropy and the second law of thermodynamics in an introductory physics course

We report on students’ thinking regarding entropy in an introductory calculus-based physics course. We analyzed students’ responses to a variety of questions on entropy changes of an arbitrarily defined system and its surroundings. In four offerings of the same course we found that before instruction, no more than 6% of all students could give completely correct responses to relevant questions posed in both general and concrete contexts. Nearly two-thirds of the students showed clear evidence of conservation-type reasoning regarding entropy. These outcomes were little changed even after instruction. Targeted instruction that guided students to recognize that entropy is not a conserved quantity appears to yield improved performance on qualitative questions related to this concept.

The future of physics education research: Intellectual challenges and practical concerns

of e a ch of ning During the World Year of Physics, much effort is bein made to celebrate the unprecedented advances in our u standing of the physical world made during the past cent However, we have not yet seen comparable advances in understanding of student learning of our discipline. One p sible explanation is that learning is inherently more comp than most physical processes. Although this explanatio plausible, we have not made similar systematic efforts understand student learning. The enormous effort expen by many physics instructors over the past century was harnessed in a way that made cumulative progress likely Lillian McDermott has observed, ‘‘Unless we are willing t apply the same rigorous standards of scholarship to is related to learning and teaching that we regularly apply more traditional research, the present situation in phy education is unlikely to change.’’ 1