This study explored the nature of the integration of the five components of pedagogical content knowledge (PCK): (a) Orientations toward Teaching Science, (b) Knowledge of Student Understanding, (c) Knowledge of Instructional Strategies and Representations, (d) Knowledge of Science Curriculum, and (e) Knowledge of Assessment of Science Learning. Given the topic and context specificity of PCK, this investigation was conducted in the context of the photosynthesis and heredity instruction of four teachers who were working at the same high school with the same curricular materials. Data sources included classroom observations, semi‐structured interviews, lesson plans, instructional materials, and students' work samples. Data were analyzed through three different approaches: (a) in‐depth analysis of explicit PCK, (b) enumerative approach, and (c) the constant comparative method. Data analysis indicated five salient features of the integration of the PCK components: (a) the integration of the components was idiosyncratic and topic‐specific; (b) Knowledge of Student Understanding and Knowledge of Instructional Strategies and Representations were central in the integration; (c) Knowledge of Science Curriculum and Knowledge of Assessment of Science Learning had most limited connection with other components; (d) Knowledge of Assessment of Science Learning was more often connected with Knowledge of Student Understanding and Knowledge of Instructional Strategies and Representations than with the other components; and (e) Didactic Orientations toward Teaching Science directed Knowledge of Instructional Strategies and Representations inhibiting its connection with other components. This study highlights that the quality of PCK depends on the coherence among the components as well as the strength of individual components. From a methodological perspective, this study demonstrates the possibility to make PCK more visible and accessible by using a PCK Map, a pictorial representation of the interactions of the PCK components. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 922–941, 2012

This study tested a hypothesis that focused on whether or not teachers' pedagogical content knowledge (PCK) is a necessary body of knowledge for reformed science teaching. This study utilized a quantitative research method to investigate the correlation between a teacher's PCK level as measured by the PCK rubric (Park et al. 2008) and the degree to which his/her classroom is reform-oriented as measured by RTOP (Sawada et al. 2002). Data included 33 instructional sessions of photosynthesis and heredity videotaped with 7 high school biology teachers. Each session was given a score on both the PCK rubric and RTOP by two independent raters. Results indicate that PCK score is significantly related to RTOP score in terms of both total score (r=.831, p<.01) and subcomponent scores (ranging from r=.616 to .805, p<.01). Implications for science teacher education and future research are discussed.

Argumentation is a core practice of science that inherently contains uncertainty. Relatively few studies have examined the role of uncertainty within argumentation and how teachers manage uncertainty leading to conceptual development. This design-based, multiple-case study employed the constant K E Y W O R D S argumentation, dialogue, epistemic understanding, managing uncertainty, social negotiation

This quasi‐experimental and pre/posttest study was designed to examine whether fourth‐grade students who engaged in collaboratively writing letters to 11th‐grade students performed better on tests of conceptual understanding of a unit on force and motion than students who did not. The participants included 835 fourth‐grade students and 416 11th‐grade students from four elementary schools and one high school in the United States. Students in treatment groups were asked to write three letters for exchange at the beginning/during/completion of an 8‐week teaching unit about force and motion. The structure of writing was based on three components of arguments: question, claim, and evidence. A comparison of the pre‐ and posttest results indicated that students who engaged in collaborative letter‐writing tasks performed better than students who did not. The pre‐ and posttest results also showed that female, special, low socioeconomic status, and gifted students benefited the most from the collaborative letter‐writing tasks. Through the letter‐writing exchange activities, the fourth‐grade students were supported and encouraged to learn difficult concepts by the 11th‐grade students. The more the 11th graders asked the fourth graders for explanation and clarification of the concepts in the letters, the more the fourth‐grade students learned. Two factors related to argumentative writing were identified as predictors of success on students’ achievement tests: overall cohesiveness, with an emphasis on embedding multiple modal representations in the text and the strength of the relationship between claims and evidence. This study suggests that there is a pedagogical need to build support structures to help students understand the role of audience, the function of multiple modal representations, and the quality of evidence for supporting knowledge claims in argumentative writing, as this could lead to a better understanding of scientific concepts. © 2013 Wiley Periodicals, Inc. Sci Ed 97:745–771, 2013

We demonstrate that laser beams can be converged toward a light-absorbing target through optically diffusive media by using photoacoustic-guided interferometric focusing. The convergence of light is achieved by shaping the wavefront of the incident light with a deformable mirror to maximize the photoacoustic signal, which is propor tional to the scattered light intensity at the light absorber.

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This study implemented an online peer assessment activity to help 52 Taiwanese in-service science and mathematics teachers to develop research proposals in an educational research course. The participants were divided into 16 groups, and each group was required to submit a proposal via three rounds of online peerassessment activity. This study found that, through the online peer-assessment activity, the in-service teachers could enhance their proposals at the initial stage of the activity, but there was almost no substantial improvement at the later stage. In addition, the amount of feedback they obtained was positively related to the performance from the first round to the second round; however, few significant relationships were found from the second to the third round. This study also showed that the process of peer assessment could be used to clarify assessment criteria and that sufficient support from the instructor can maintain participants' attitudes towards this activity, which were relatively optimistic throughout.

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