Robert J. Dufresne

Classtalk: A Classroom Communication System for Active Learning

TRADITIONAL METHODS for teaching science courses at the post-secondary level employ a lecture format of instruction in which the majority of students are passively listening to the instructor and jotting down notes. Current views of learning and instruction challenge the wisdom of this traditional pedagogic practice by stressing the need for the learner to play an active role in constructing knowledge. The emerging technology of classroom communication systems offers a promising tool for helping instructors create a more interactive, student-centered classroom, especially when teaching large courses. In this paper we describe our experiences teaching physics with a classroom communication system calledClasstalk. Classtalk facilitated the presentation of questions for small group work as well as the collection of student answers and the display of histograms showing how the class answered, all of which fed into a class-wide discussion of students’ reasoning. We foundClasstalk to be a useful tool not only for engaging students in active learning during the lecture hour but also for enhancing the overall communication within the classroom. Equally important, students were very positive aboutClasstalk-facilitated instruction and believed that they learned more during class than they would have during a traditional lecture.

The relation between problem categorization and problem solving among experts and novices.

These investigations were conducted to examine the relationship between problem-solving ability and the criteria used to decide that two classical mechanics problems would be solved similarly. We began by comparing experts and novices on a similarity judgment task and found that the experts predominantly relied on the problems’ deep structures in deciding on similarity of solution, although the presence of surface-feature similarity had a clear adverse effect on performance. The novices relied predominantly on surface features, but were capable of using the problems’ deep structures under certain conditions. In a second experiment, we compared groups of novices, at the same level of experience, who tended to employ different types of reasoning in making similarity judgments. Compared to novices who relied predominantly on surface features, novices who made greater use of principles tended to categorize problems similarly to how experts categorized them, as well as score higher in problem solving. These results suggest that principles play a fundamental role in the organization of conceptual and procedural knowledge for good problem solvers at all levels.

Using qualitative problem‐solving strategies to highlight the role of conceptual knowledge in solving problems

We report on the use of qualitative problem‐solving strategies in teaching an introductory, calculus‐based physics course as a means of highlighting the role played by conceptual knowledge in solving problems. We found that presenting strategies during lectures and in homework solutions provides an excellent opportunity to model for students the type of concept‐based, qualitative reasoning that is valued in our profession, and that student‐generated strategies serve a diagnostic function by providing instructors with insights on students’ conceptual understanding and reasoning. Finally, we found strategies to be effective pedagogical tools for helping students both to identify principles that could be applied to solve specific problems, as well as to recall the major principles covered in the course months after it was over.

Solving physics problems with multiple representations

We present a teaching strategy to encourage flexible, non algorithmic problem solving. Students create several problem representations to answer questions about a single problem situation. Through reflection students learn the value of non algebraic representations for analyzing and solving physics problems.

Assessing-To-Learn: Formative Assessment in Physics Instruction

Assessment designed to enhance teaching and learning is called “formative assessment.” During formative assessment, teachers and students seek information about the state of student learning and then use the acquired information to adapt teaching and learning to meet student needs. “Classroom formative assessment” (CFA) requires that teachers explicitly engage in formative assessment during classroom learning activities. At a basic level, CFA occurs naturally and is a common part of most instructional settings. Nevertheless, the systematic practice of CFA is rare in secondary and post-secondary science education. Here we provide suggestions for those interested in formative assessment for use in teaching introductory physics. A simple model of classroom formative assessment is presented. Included are examples of formative assessment activities and suggestions for implementation.

Marking sense of students' answers to multiple-choice questions

A detailed example is used to illustrate the difficulties making sense of students’ answers to multiple-choice questions. We explore how correct answers can be false indicators of student knowledge and understanding. We caution against excessive reliance on multiple-choice questions for instructional decisions.

Promoting active learning in large classes using a classroom communication system

We provide an overview of an instructional strategy aimed at promoting active learning in introductory physics courses. Although a classroom communication system called Classtalk was used to facilitate the interactions among students, and between the students and the instructor, the use of Classtalk is not essential for implementing the instructional strategies described herein. A major focus of this article is a discussion of the types of questions that we have found work well in generating group, and class-wide discussions of physics concepts. We also discuss the types of reasoning used by students to answer specific conceptual questions.

How novice physics students deal with explanations

An extensive study was conducted of students’ explanations written in response to ‘what if...?’ questions in elementary mechanics. The study showed that the structure of students’ explanations yields roughly the same ranking of students as do problem‐solving tests, but in addition provides a wealth of insights into (1) context dependence and categorization in students’ use of concepts, (2) the effect of misconceptions on context dependence, and (3) the types of explanations that students tend to produce. A follow‐up study, in which students were presented with pairs of pre‐written explanations to ‘what if...?’ questions and asked to indicate a preference, showed that students do not necessarily prefer the types of explanations they write, and have greater difficulty assessing the correctness of explanations that are counter to preference type. Evidence is presented that, for many students, the links between physics thinking and real‐world thinking are all too tenuous.

Springbok: The physics of jumping

The physics of jumping is explored for a simple spring-loaded toy. The toy is easy to make and easy to analyze using an elementary Hooke’s law model. Possible uses in introductory physics are described. Conceptual and pedagogical issues are discussed

A coordination class analysis of judgments about animated motion

We use the coordination class construct to analyze interviews in which college students judged the realism of animated depictions of balls rolling on a set of tracks. We find the elements of coordination classes (readout strategies and the causal net) useful for understanding the interviewed students’ decision‐making processes. We find limited evidence for integration and invariance, the performance criteria of coordination classes.