This article concerns a lacuna in chemistry students' reasoning about chemical bonding. Although chemistry students are familiar with the charges that make up the atom––both positive and negative––they refer only to the attraction between unlike charges. Specifically, they ignore the repulsion between the positive nuclei. We named this disregard of repulsion the lacuna of repulsion. Repulsion is a crucial component in the force-based explanation of chemical bonding, presenting the bond as a dynamic equilibrium between attraction and repulsion electrical forces. We noticed this lacuna incidentally while interviewing chemistry students for a bigger project aimed at supporting students in understanding the force-based explanation of chemical bonding. This article describes our systematic qualitative study of the lacuna of repulsion and its impact on mental models of 23 high school chemistry students. Our findings show that students use six mental models, most of them built upon each other. Beginning from a simple mental model that describes the chemical bond as electrons, continuing with the including attraction forces, and completing with repulsion and a dynamic view of the bond. Only when one considers both attraction and repulsion forces and understands the dynamic balance between them is it possible to build the force-based dynamic mental model of chemical bonding. 相似文献
Today’s society is continuously coping with sustainability‐related complex issues in the Science‐Technology‐Environment‐Society (STES) interfaces. In those contexts, the need and relevance of the development of students’ higher‐order cognitive skills (HOCS) such as question‐asking, critical‐thinking, problem‐solving and decision‐making capabilities within science teaching have been argued by several science educators for decades. Three main objectives guided this study: (1) to establish “base lines” for HOCS capabilities of 10th grade students (n = 264) in the Israeli educational system; (2) to delineate within this population, two different groups with respect to their decision‐making capability, science‐oriented (n = 142) and non‐science (n = 122) students, Groups A and B, respectively; and (3) to assess the pre‐post development/change of students’ decision‐making capabilities via STES‐oriented HOCS‐promoting curricular modules entitled Science, Technology and Environment in Modern Society (STEMS). A specially developed and validated decision‐making questionnaire was used for obtaining a research‐based response to the guiding research questions. Our findings suggest that a long‐term persistent application of purposed decision‐making, promoting teaching strategies, is needed in order to succeed in affecting, positively, high‐school students’ decision‐making ability. The need for science teachers’ involvement in the development of their students’ HOCS capabilities is thus apparent. 相似文献
Journal of Science Education and Technology - Complex systems are made up of many entities, whose interactions emerge into distinct collective patterns. Computational modeling platforms can provide... 相似文献
A number of psychometricians have suggested that parallel analysis (PA) tends to yield more accurate results in determining the number of factors in comparison with other statistical methods. Nevertheless, all too often PA can suggest an incorrect number of factors, particularly in statistically unfavorable conditions (e.g., small sample sizes and low factor loadings). Because of this, researchers have recommended using multiple methods to make judgments about the number of factors to extract. Implicit in this recommendation is that, when the number of factors is chosen based on PA, uncertainty nevertheless exists. We propose a Bayesian parallel analysis (B-PA) method to incorporate the uncertainty with decisions about the number of factors. B-PA yields a probability distribution for the various possible numbers of factors. We implement and compare B-PA with a frequentist approach, revised parallel analysis (R-PA), in the contexts of real and simulated data. Results show that B-PA provides relevant information regarding the uncertainty in determining the number of factors, particularly under conditions with small sample sizes, low factor loadings, and less distinguishable factors. Even if the indicated number of factors with the highest probability is incorrect, B-PA can show a sizable probability of retaining the correct number of factors. Interestingly, when the mode of the distribution of the probabilities associated with different numbers of factors was treated as the number of factors to retain, B-PA was somewhat more accurate than R-PA in a majority of the conditions. 相似文献
ABSTRACTIn theory, both virtual manipulatives and explicit instruction are viable options to support students with disabilities as they learn mathematics. This study explored the effect of a treatment package—an app-based virtual manipulative (Cuisenaire® Rods) in conjunction with explicit instruction—on students’ acquisition and generalization of solving problems involving division of whole numbers with remainders. Three middle school students with disabilities participated in this multiple baseline, multiple probe across participants single case design study. Each of the students acquired the mathematical behavior of being able to solve division with remainders problems. In other words, a functional relation existed between the intervention package of explicit instruction and the Cuisenaire® Rods app-based manipulative and students’ accuracy in solving division with remainders problems. Yet, two students failed to generalize the skill without the explicit instruction and use of the app-based manipulative. 相似文献
Teachers are central to providing high-quality science learning experiences called for in recent reform efforts, as their understanding of science impacts both what they teach and how they teach it. Yet, most elementary teachers do not enter the profession with a particular interest in science or expertise in science teaching. Research also indicates elementary schools present unique barriers that may inhibit science teaching. This case study utilizes the framework of identity to explore how one elementary classroom teacher’s understandings of herself as a science specialist were shaped by the bilingual elementary school context as she planned for and provided reform-based science instruction. Utilizing Gee’s (2000) sociocultural framework, identity was defined as consisting of four interrelated dimensions that served as analytic frames for examining how this teacher understood her new role through social positioning within her school. Findings describe the ways in which this teacher’s identity as a science teacher was influenced by the school context. The case study reveals two important implications for teacher identity. First, collaboration for science teaching is essential for elementary teachers to change their practice. It can be challenging for teachers to form an identity as a science teacher in isolation. In addition, elementary teachers new to science teaching negotiate their emerging science practice with their prior experiences and the school context. For example, in the context of a bilingual school, this teacher adapted the reform-based science curriculum to better meet the unique linguistic needs of her students.