Lillian C. McDermott

Research on conceptual understanding in mechanics

Over the past decade, physicists, psychologists and science educators have been conducting research that has yielded detailed information about how students learn physics. Some investigators have used physics as a context for examining cognitive processes and approaches to problem‐solving. For others, the primary emphasis has been on conceptual understanding in a particular area of physics such as mechanics, electricity, heat or optics. Regardless of the motivation behind the research, the results indicate that similar difficulties occur among students of different ages and ability, often in spite of formal study in physics. The persistence of these difficulties suggests that they are not easily overcome, and need to be addressed explicitly during instruction.

Resource Letter: PER-1: Physics Education Research

The purpose of this Resource Letter is to provide an overview of research on the learning and teaching of physics. The references have been selected to meet the needs of two groups of physicists engaged in physics education. The first is the growing number whose field of scholarly inquiry is (or might become) physics education research. The second is the much larger community of physics instructors whose primary interest is in using the results from research as a guide for improving instruction.

Student difficulties in connecting graphs and physics: Examples from kinematics

Some common errors exhibited by students in interpreting graphs in physics are illustrated by examples from kinematics. These are taken from the results of a descriptive study extending over a period of several years and involving several hundred university students who were enrolled in a laboratory‐based preparatory physics course. Subsequent testing indicated that the graphing errors made by this group of students are not idiosyncratic, but are found in different populations and across different levels of sophistication. This paper examines two categories of difficulty identified in the investigation: difficulty in connecting graphs to physical concepts and difficulty in connecting graphs to the real world. Specific difficulties in each category are discussed in terms of student performance on written problems and laboratory experiments. A few of the instructional strategies that have been designed to address some of these difficulties are described.

Research as a guide for curriculum development: An example from introductory electricity. Part I: Investigation of student understanding

A method of and apparatus for determining the quantity of phenols in an aqueous solution after treating the solution to remove interfering impurities therefrom. The treated aqueous solution is electrolytically alternately converted so as to be either acidic or basic with preselected and controlled pH values. These acidic and basic solutions are subjected to ultraviolet radiation at a preselected wavelength so that the amount of radiation passing therethrough at the preselected pH values can be measured. The measured amounts of ultraviolet radiation passing through the acidic and basic solutions are compared to determine the concentration of phenols in the aqueous solution.

Investigation of student understanding of the concept of velocity in one dimension

This paper describes a systematic investigation of the understanding of the concept of velocity among students enrolled in a wide variety of introductory physics courses at the University of Washington. The criterion selected for assessing understanding of a kinematical concept is the ability to apply it successfully in interpreting simple motions of real objects. The primary data source has been the individual demonstration interview in which students are asked specific questions about simple motions they observe. Results are reported for the success of different student populations in comparing velocities for two simultaneous motions. It appears that virtually every failure to make a proper comparison can be attributed to use of a position criterion to determine relative velocity. Some implications for instruction are briefly discussed.

Investigation of student understanding of the concept of acceleration in one dimension

This paper describes a systematic investigation of the understanding of the concept of acceleration among students enrolled in a variety of introductory physics courses at the University of Washington. The criterion for assessing understanding of a kinematical concept is the ability to apply it successfully in interpreting simple motions of real objects. The main thrust of this study has been on the qualitative understanding of acceleration as the ratio Δv/Δt. The primary data source has been the individual demonstration interview in which students are asked specific questions about simple motions they observe. Results are reported for the success of different student populations in comparing accelerations for two simultaneous motions. Failure to make a proper comparison was due to various conceptual difficulties which are identified and described. Some implications for instruction are briefly discussed.

Oersted Medal Lecture 2001: “Physics Education Research—The Key to Student Learning”

Research on the learning and teaching of physics is essential for cumulative improvement in physics instruction. Pursuing this goal through systematic research is efficient and greatly increases the likelihood that innovations will be effective beyond a particular instructor or institutional setting. The perspective taken is that teaching is a science as well as an art. Research conducted by physicists who are actively engaged in teaching can be the key to setting high (yet realistic) standards, to helping students meet expectations, and to assessing the extent to which real learning takes place.

Research as a guide for curriculum development: An example from introductory electricity. Part II: Design of instructional strategies

This is the second of two closely related articles that together describe how results from research can be used as a guide for curriculum development. The first article shows how the investigation of student understanding of electric circuits by the Physics Education Group has contributed to the building of a research base. This second article describes how the group has drawn on this resource both in developing a curriculum for laboratory‐based instruction and in adapting this curriculum to fit the constraints of a traditional introductory course. Also discussed is how, in turn, development and implementation of the curriculum have enriched the research base.

An investigation of student understanding of the real image formed by a converging lens or concave mirror

Student understanding of the real images produced by converging lenses and concave mirrors was investigated both before and after instruction in geometrical optics. The primary data were gathered through interviews in which undergraduates taking introductory physics were asked to perform a set of prescribed tasks based on a simple demonstration. The criterion used to assess understanding was the ability to apply appropriate concepts and principles, including ray diagrams, to predict and explain image formation by an actual lens or mirror. Performance on the tasks, especially by students who had not had college instruction in geometrical optics, suggested the presence of certain naive conceptions. Students who had just completed the study of geometrical optics in their physics courses were frequently unable to relate the concepts, principles, and ray‐tracing techniques that had been taught in class to an actual physical system consisting of an object, a lens or a mirror, and a screen. Many students did not...

A perspective on teacher preparation in physics and other sciences: The need for special science courses for teachers

This article proceeds from the premise that one of the major reasons for the perceived crisis in science education is the failure of our colleges and universities to provide the type of preparation that precollege teachers need to teach science effectively. The perspective taken is based on many years of teaching physics and physical science to prospective and practicing teachers at all grade levels. The inadequacy of the present system of preparing teachers is examined and an argument is presented for offering special physics courses for teachers. Experience at the University of Washington provides the basis for a discussion of the type of intellectual objectives and instructional methods that should characterize such courses.