| Abstract
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The phrase "nature of science" has been used to refer to "the epistemology of science, science as a way of knowing, or the values and beliefs inherent to the development of scientific knowledge" (Lederman, Abd-El-Khalick, Bell, & Schwartz, 2002, p. 497). Despite the disagreement about specific definitions, some aspects of NOS are shared and considered non-controversial and accessible to K-12 students. These aspects are that scientific knowledge is: "tentative (subject to change); empirically-based (based on and/or derived from observations of the natural world); theory-laden; partially based on human inference, imagination and creativity; and socially and culturally embedded" (Abd-El-Khalick & Lederman, 2000b, p. 1063). Four other aspects of NOS that have been emphasized are the distinction between observation and inferences, the relationship between theories and laws, the myth of the scientific method, and the social dimension of scientific knowledge (Abd-El-Khalick, 1998; Akerson & Abd-El-Khalick, 2000). This study aimed to assess the influence of an explicit-reflective, metacognitive, content-embedded instructional approach undertaken from within a learning-as-conceptual change framework on inservice middle and high school science teachers' understandings of NOS. The study also aimed to examine whether this instructional approach would enable participant teachers to translate their NOS understandings into actual classroom practices, as well as document the factors that facilitate or hinder such translation. The study was guided by the following research questions: (a) What is the impact of the intervention on participant teachers' understandings of several target aspects of NOS? (b) What is the impact of the intervention on participant teachers' instructional planning and delivery related to NOS? (c) What factors mediate (i.e., enhance or impede) the translation of teachers' NOS understandings into instructional practice? The study used a pretest, posttest single-group design to assess the impact of the first phase of the intervention on participants' understandings of NOS. This phase was delivered during a six-week professional development program for 19 middle and high school inservice science teachers serving in different Palestinian governmental schools. Next, a multiple case-study approach was used to examine the differential enactment of NOS instruction in the case of a sub-sample of six participants randomly selected from those who reflected substantial growth in terms of their NOS understandings. This focus group was then randomly divided into two focus groups of three. The first three participants were provided support as they implemented NOS instruction in their classrooms, while the other three in the second focus group did not receive such support. This differentiated support created a context that allowed the examination of factors that facilitate or impede the translation of participants' NOS understandings into classroom practice. The study was conducted in two phases. During the first phase, participants were administered the Views of Nature of Science Questionnaire-Form C (VNOS-C) (Lederman et al., 2002) at the beginning and conclusion of the workshop, as well as after five months of the study. Each administration was coupled with individual follow-up, semi-structured interviews with a sub-sample of four randomly selected participants. These data were used to assess the impact of the workshop on participants' NOS conceptions and to select a sub-sample of six participants to follow during the second phase of the study. During the second phase, the six participants in the two focus groups planned for selected science units and implemented these units in their classrooms. This phase aimed to investigate the impact of the intervention and acquired NOS understandings on participants' instructional planning and delivery related to NOS, and to understand the factors and scaffolds that mediate the translation of participants' understandings into practice. The data collected during this phase were derived from classroom observations, pre-post interviews, teachers' diaries, and instructional artifacts. (Abstract shortened by UMI.)
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