Teaching elements of nature of science: A yearlong case study of a fourth‐grade teacher

This study examined and supported the efforts of Tina, an experienced elementary teacher, in helping her fourth graders internalize informed views of the inferential, tentative, and creative nature of science (NOS). Tina held informed views of, and was motivated to teach about, NOS. The study aimed to answer the following question: What specific supports were needed to enable Tina to make the target NOS elements explicit in her teaching? The lead researcher visited Tina's classroom every week and interacted with her on a continuous basis. Data sources included classroom observations and videotapes, teacher NOS questionnaires and associated interviews, teacher–researcher communications, and teacher and researcher logs. Although Tina's understandings and intentions were necessary to enable her to teach about NOS, they were not sufficient. Tina needed support to translate her NOS views and intentions into pedagogically appropriate instructional activities that would make the target NOS aspects accessible to her students. Socially mediated support was needed at the personal level in terms of helping Tina activate her tacit NOS understandings, and at the professional level in terms of modeling explicit NOS instruction in Tina's own classroom by the lead researcher. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 1025–1049, 2003     

The Relation of Career Indecision and Parental Attachment among Iranian Undergraduate Students

Career indecision particularly among college and undergraduate students is a concern of counselors and psychologists. This concern has led to numerous research studies related to career indecision and factors that influence it, such as family relationships. In this regard, several studies have reported a significant relationship between career indecision and parental attachment. However, little research has been undertaken on the influence of this factor in regard to career indecision for Iranian students. For this purpose, 158 Iranian freshmen and sophomores who had completed the ‘Career Decision Scale’ (Osipow et al., Journal of Vocational Behavior 9:233–243, 1976) and had been identified as career-undecided, completed the ‘Inventory of Parents and Peer Attachment-Revised’ (Armsden & Greenberg, Journal of Youth and Adolescence 16:427–453, 1987). The results revealed that a significant negative relationship was found between career indecision and attachment to mother, whilst the relationship between career indecision and attachment to father was not significant. However, regression analysis showed parental attachment did not significantly predict career indecision of students. Implications and recommendations for further research are discussed.     

The Student Actions Coding Sheet (SACS): An instrument for illuminating the shifts toward student‐centered science classrooms

This study describes the development of an instrument to investigate the extent to which student‐centered actions are occurring in science classrooms. The instrument was developed through the following five stages: (1) student action identification, (2) use of both national and international content experts to establish content validity, (3) refinement of the item pool based on reviewer comments, (4) pilot testing of the instrument, and (5) statistical reliability and item analysis leading to additional refinement and finalization of the instrument. In the field test, the instrument consisted of 26 items separated into four categories originally derived from student‐centered instruction literature and used by the authors to sort student actions in previous research. The SACS was administered across 22 Grade 6–8 classrooms by 22 groups of observers, with a total of 67 SACS ratings completed. The finalized instrument was found to be internally consistent, with acceptable estimates from inter‐rater intraclass correlation reliability coefficients at the p < 0.01 level. After the final stage of development, the SACS instrument consisted of 24 items separated into three categories, which aligned with the factor analysis clustering of the items. Additionally, concurrent validity of the SACS was established with the Reformed Teaching Observation Protocol. Based on the analyses completed, the SACS appears to be a useful instrument for inclusion in comprehensive assessment packages for illuminating the extent to which student‐centered actions are occurring in science classrooms.     

Representations of nature of science in high school chemistry textbooks over the past four decades

This study assessed the representations of nature of science (NOS) in high school chemistry textbooks and the extent to which these representations have changed during the past four decades. Analyses focused on the empirical, tentative, inferential, creative, theory‐driven, and social NOS, in addition to the myth of “The Scientific Method,” the nature of scientific theories and laws, and the social and cultural embeddedness of science. A total of 14 textbooks, including five “series” spanning one to four decades, were analyzed. The textbooks commanded significant market shares in the United States and were widely used in some of the most populace states. Relevant textbook sections were scored on each of the target NOS aspects on a scale ranging from −3 to +3, which reflected the accuracy, completeness, and manner (explicit versus implicit) in which these aspects were addressed. The textbooks fared poorly in their representations of NOS. Additionally, with a few exceptions, textbook scores either did not change or decreased over the past four decades. These trends are incommensurate with the discourse in national and international science education reform documents, which has witnessed an increasing emphasis on the centrality of NOS to scientific literacy and pre‐college science education during the same time period. Assessment and evaluation strategies, and policies need to be targeted if substantial and desired changes in the ways NOS is addressed in science textbooks are to be effected. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 835–855, 2008     

Scientific reasoning and epistemological commitments: Coordination of theory and evidence among college science students

Reasoning skills are major contributors to academic and everyday life success. Epistemological commitments (ECs) are believed to underlie reasoning processes and, when considered, could do much in delineating the complex nature of scientific reasoning. This study examined the relationship between ECs and scientific reasoning among college science students. Prior knowledge (PK) was factored in as an intervening variable. Participants were 139 college students enrolled in two physics courses in a large Midwestern university. They completed an online questionnaire, which assessed their PK regarding buoyancy in liquids and EC to the consistency of theory with evidence. Responses to the online questionnaire were used to select 40 participants with varying levels of PK and EC. These participants were divided into four groups, each with 10 students, representing four conditions: High PK–High EC, High PK–Low EC, Low PK–High EC, and Low PK–Low EC. These groups allowed using a 2 × 2 factorial quasi‐experimental design to examine the relationship between participants' reasoning and ECs, accounting for their PK. The quality of participants' reasoning was assessed during individual interviews, which presented them with four problem‐solving tasks involving objects immersed in water. Two‐way analysis of variance (ANOVA) indicated the absence of interaction between PK and EC. The results showed that the higher the ECs were, the higher the quality of reasoning was for comparable levels of PK. Additionally, it was found that PK impacted reasoning more strongly when ECs were weaker. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1064–1093, 2010     

Homomorphic image watermarking with a singular value decomposition algorithm

In this paper, a new homomorphic image watermarking method implementing the Singular Value Decomposition (SVD) algorithm is presented. The idea of the proposed method is based on embedding the watermark with the SVD algorithm in the reflectance component after applying the homomorphic transform. The reflectance component contains most of the image features but with low energy, and hence watermarks embedded in this component will be invisible. A block-by-block implementation of the proposed method is also introduced. The watermark embedding on a block-by-block basis makes the watermark more robust to attacks. A comparison study between the proposed method and the traditional SVD watermarking method is presented in the presence of attacks. The proposed method is more robust to various attacks. The embedding of chaotic encrypted watermarks is also investigated in this paper to increase the level of security.