This paper discusses the existing dichotomy regarding the definition of weight and its implicatio... more This paper discusses the existing dichotomy regarding the definition of weight and its implications in science education. The history and epistemology of the weight concept and its present status in instruction and students' knowledge about weight are reviewed. The rationale of the concept of gravitational weight, currently accepted in many textbooks, is critiqued. Two mutually related implications stem from this study in science teaching: a conceptual distinction between weight and gravitational force; and replacement of the gravitational definition of weight by the operational one. Both innovations may improve the quality of science education.
This paper reports on a study that was designed to investigate the knowledge about image formatio... more This paper reports on a study that was designed to investigate the knowledge about image formation exhibited by students following instruction in geometrical optics in an activity-based college physics course for prospective elementary teachers. Students were interviewed individually, using several tasks involving simple apparatus (plane and curved mirrors, lenses, and prisms). The diagrams drawn by the students and the verbal comments they made provide evidence that their knowledge can be described as an intermediate state, a hybridization of preinstruction knowledge (which is dominated by a holistic conceptualization) and formal physics knowledge. We infer from our data the core concepts and main ideas of the postinstruction students' hybrid knowledge. Finally, by comparing preinstruction and formal physics conceptualizations of image formation we argue that a strong type of knowledge restructuring (in the sense
This paper discusses the existing dichotomy regarding the definition of weight and its implicatio... more This paper discusses the existing dichotomy regarding the definition of weight and its implications in science education. The history and epistemology of the weight concept and its present status in instruction and students' knowledge about weight are reviewed. The rationale of the concept of gravitational weight, currently accepted in many textbooks, is critiqued. Two mutually related implications stem from this study in science teaching: a conceptual distinction between weight and gravitational force; and replacement of the gravitational definition of weight by the operational one. Both innovations may improve the quality of science education.
This paper reports on a study that was designed to investigate the knowledge about image formatio... more This paper reports on a study that was designed to investigate the knowledge about image formation exhibited by students following instruction in geometrical optics in an activity-based college physics course for prospective elementary teachers. Students were interviewed individually, using several tasks involving simple apparatus (plane and curved mirrors, lenses, and prisms). The diagrams drawn by the students and the verbal comments they made provide evidence that their knowledge can be described as an intermediate state, a hybridization of preinstruction knowledge (which is dominated by a holistic conceptualization) and formal physics knowledge. We infer from our data the core concepts and main ideas of the postinstruction students' hybrid knowledge. Finally, by comparing preinstruction and formal physics conceptualizations of image formation we argue that a strong type of knowledge restructuring (in the sense
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Papers by Dan Roginsky