Uri Ganiel

Potential difference and current in simple electric circuits: A study of students’ concepts

A study which was designed to identify students’ concepts of simple electric circuits is reported. A diagnostic questionnaire was administered to a sample of 145 high school students and 21 physics teachers. The questionnaire included mainly qualitative questions which were designed to examine students’ understanding of the functional relationships between the variables in an electric circuit. The main findings obtained from the analysis of the responses are current is the primary concept used by students, whereas potential difference is regarded as a consequence of current flow, and not as its cause. Consequently students often use V=IR incorrectly. A battery is regarded as a source of constant current. The concepts of emf and internal resistance are not well understood. Students have difficulties in analyzing the effect which a change in one component has on the rest of the circuit. This is probably due to the more general difficulty students have in dealing with a simultaneous change of several variables.

Macro‐micro relationships: the missing link between electrostatics and electrodynamics in students’ reasoning

In analysing students’ reasoning about simple electric circuits, it is useful to think in terms of three aspects: (a) quantitative relationships, which are defined by algebraic expressions between circuit parameters; (6) functional relationships, which involve qualitative considerations, and lead to a correct description of the interplay between circuit variables; and (c) processes involving macro‐micro relationships, where the macroscopic circuit parameters are tied with microscopic models and rules. We argue that all three aspects are necessary for a proper understanding of the topic. While there is considerable information about the first two aspects with regard to student reasoning, little is known about the third. In this study, we have investigated this aspect with students in an advanced high school course. We find that even in very simple situations, most students do not tie concepts from electrostatics into their description of the phenomena. This leads to severe inconsistencies in student answer...

Macroscopic phenomena and microscopic processes: Student understanding of transients in direct current electric circuits

Studies of student understanding of simple electric dc circuits have shown that many of them find it very difficult to apply qualitative reasoning to explain the observed phenomena. It has been suggested that these difficulties may be due to their failure to construct models of microscopic processes that lead to these phenomena. Indeed, in the traditional courses, such models have generally not been emphasized. In the present study, we compared the performance of different groups of university students in answering a questionnaire designed to probe their understanding of the relationship between macroscopic phenomena of transients in a dc circuit and the microscopic processes that can explain these phenomena. One group studied from a traditional text, the second group used a recently developed text that emphasizes models of microscopic processes. We also conducted detailed interviews with some of the students. From an analysis of the performance of these two groups, and also from a comparison with a previ...

From Fragmented Knowledge to a Knowledge Structure: Linking the Domains of Mechanics and Electromagnetism.

The traditional teaching of physics in separate domains leads to a fragmented knowledge structure that has an adverse effect on the comprehension and recall of the central ideas. We describe a new program: MAOF (“overview” in Hebrew), which relates large parts of mechanics and electromagnetism to each other via the key concepts of field and potential, and at the same time treats students’ conceptual difficulties. The MAOF program can accompany any conventional course in mechanics and electromagnetism as part of the review process. The instructional model integrates problem solving, conceptual understanding, and the construction of a knowledge structure. It consists of five stages: solve, reflect, conceptualize, apply, and link. In order to construct the relationships within a domain, students solve simple and familiar problems, reflect on their solution methods, identify the underlying principles, and represent them in visual form, forming concept maps. Additional activities deal with conceptual difficult...

Proactive and Retroactive Facilitation of Long-Term Retention by Curriculum Continuity

A longitudinal research study was designed to investigate effects of mutual interrelations between courses in sequential teaching on long-term retention of learning. This paper mainly relates to the following question: Is the retention of previously learned course material facilitated by new content taught in subsequent courses? Students were followed up for 3 consecutive years from junior to senior high school. Two groups were investigated: Both had studied the same introductory physical science course in grade 7, but only one group continued to study related physical science topics in grade 8. Analysis of longitudinally matched data detected significant proactive and retroactive effects of courses: (a) Prior knowledge acquired in grade 7 facilitated further learning in grade 8; and (b) retention of the grade 7 subject matter over a 2-year interval was higher in the group that had studied physical science continuously during grades 7 and 8. These long-lasting effects are not due to mere rehearsal, since the content of the grade 7 course is used but not retaught in subsequent courses. Explanations are provided by Ausubel’s assimilation theory. The main educational implication is that a program composed of a hierarchical sequence of learning units is superior to a discontinuous array of discrete courses.

Explaining the Unexplainable: Translated Scientific Explanations (TSE) in public physics lectures

This paper deals with the features and design of explanations in public physics lectures. It presents the findings from a comparative study of three exemplary public physics lectures, given by practicing physicists who are acknowledged as excellent public lecturers. The study uses three different perspectives: the lecture, the lecturer, and the audience (high school physics teachers and students). It concludes with a grounded theory explanatory framework for public physics lectures. The framework demonstrates that a “Translated Scientific Explanation” (TSE) draws upon four clusters of explanatory categories: analogical approach, story, knowledge organization, and content. The framework suggests how the lecturer fits the content of the presentation to the audience’s knowledge throughout the lecture, taking into account the listeners’ lack of necessary prior knowledge.

Scientific argumentation in public physics lectures: bringing contemporary physics into high-school teaching

This article presents an approach to integrating public e-lectures on contemporary physics into a traditional high-school syllabus. This approach was used in a long-distance professional development course for in-service physics teachers. Each lecture was related to a specific obligatory syllabus chapter, and was accompanied by learner-centred activities. We provide a detailed description of an activity that explicates the scientific arguments that were presented in the lectures. Teachers appreciated the approach and reported that the lectures and activities updated and broadened their knowledge of physics and contributed to their understanding of the nature of science (NOS).

Explanatory Framework for Popular Physics Lectures

Popular physics lectures provide a ‘translation’ that bridges the gap between the specialized knowledge that formal scientific content is based on, and the audiences informal prior knowledge. This paper presents an overview of a grounded theory explanatory framework for Translated Scientific Explanations (TSE) in such lectures, focusing on one of its aspects, the conceptual blending cluster. The framework is derived from a comparative study of three exemplary popular physics lectures from two perspectives: the explanations in the lecture (as artifacts), and the design of the explanation from the lecturers point of view. The framework consists of four clusters of categories: 1. Conceptual blending (e.g. metaphor). 2. Story (e.g. narrative). 3. Content (e.g. selection of level). 4. Knowledge organization (e.g. structure). The framework shows how the lecturers customized the content of the presentation to the audiences knowledge. Lecture profiles based upon this framework can serve as guides for utilizing...

Designing and using an open graphic interface for instruction in geometrical optics

Abstract Graphic representations are the main and sometimes the only effective way of communication in the domain of Geometrical Optics. Many of the conceptual difficulties students have in this domain are related to the interpretation of these representations. RAY is an open graphic interface that was designed to address these problems, serving as a teaching aid in class and as a learning environment for students. The program enables the user to create and to control various optical components such as mirrors, lenses and prisms, to produce simulated ray diagrams and to analyze them with a set of graphic tools. Since any optical setup can be easily created and explored, extensive qualitative analysis can be performed during the study, dealing with many examples of ray diagrams. Program design enables the implementation of various approaches to learning and teaching, including the ability to combine the theory and its formal representations with real demonstrations and experiments.

Electrostatics and electrodynamics‐A case of micro Versus Macro

Students’ reasoning about simple electric circuits is discussed. Following a short review of previous research findings, we report on a study which focused on how advanced high school students conceptualize the microscopic processes taking place in such circuits. We find that even in very simple situations, most students do not ties concepts from electrostatics into their description of the phenomena.Formal definitions, even when quoted correctly, are not utilized operationally. Consequently, a consistent picture of the mechanisms is usually lacking. This may explain why students cannot conceptualize the electric circuit as a system and appreciate the functional relationships between its parts.