Light propagation and visual patterns: Preinstruction learners' conceptions

Abstract

This study formed part of a project aimed at revising the instructional approach for geometrical optics in the 10th grade. The instructional intervention was based on the extensive use of a diagrammatic representation as a descriptive, explanatory, and problem-solving tool in the domain. The purpose of this study was to elicit the conceptions and representations of light propagation, image formation, and sight typical to preinstruction learners, with special attention to identifying precursors of problematic features of postinstruction students' knowledge. The premise for this study was that the difficulties students have before, during, and after traditional instruction with respect to representing optical phenomena have their origins in the fragmented prescientific knowledge constructed on the basis of experience. We believe that the difficulties persist because the key factors leading to fragmentation are not usually addressed and remedied. The main findings of the study indicate that (a) preinstruction students display some familiarity with optical systems, light propagation, and illumination patterns; (b) student-generated graphical representations describing and explaining optical phenomena display some features of formal ray tracing; (c) preinstruction students have not developed a consistent descriptive and explanatory model for light propagation; and (d) the context of sight seems to have a confounding effect on the establishment of a unified prior model for optical phenomena.

Teaching and learning geometric optics in middle school through the Turning Eyes to the Big Sky project

“…7,12 Students are better able to interpret the propagation of light when they consider it independently of sight. 20 While extending one's vision is the purpose of using a telescope, it is possible to investigate the interaction of the telescope with light without tackling how the eye sees.…”

Is it harder to know or to reason? Analyzing two-tier science assessment items using the Rasch measurement model

“…While there is a rich literature on students' conceptions (Duit 2009), science educators have realized that teachers do not have many , 1983;Fetherstonaugh and Treagust 1992;Galili and Hazan 2000;La Rosa et al 1984;Langley et al 1997). Thus, using TTMC items affords teachers access to results of this literature for uncovering students' pre-instructional understanding and reasoning about the phenomena or concepts.…”

“…Developing TTMC items draws on literature on students' alternative conceptions that have been conducted over the past 20 years or so. For example, Chu and Treagust (2009) developed the Light Propagation Diagnostic Instrument (LPDI) based on prior qualitative research studies on students' conceptions mainly about fundamental geometric optics (Andersson and Kärrqvist, 1983;Fetherstonaugh and Treagust 1992;Galili and Hazan 2000;La Rosa et al 1984;Langley et al 1997). Thus, using TTMC items affords teachers access to results of this literature for uncovering students' pre-instructional understanding and reasoning about the phenomena or concepts.…”

Understanding vision: students’ use of light and optics resources

“…At the upper-level high school and undergraduate levels, research has also been conducted on how students understand and apply the basic physical properties of light. Langley et al 3 showed that while students had some familiarity with optical systems, they were confused by a unified model of optics in which the context of sight was discussed. Saxena 4 found that while students seemingly understood the basic properties of light, they were unable to apply that knowledge to real situations.…”