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1.
There has been little research into learners' mental models of chemical bonding at any level, let alone the tertiary level. Undergraduate and graduate students encounter a plethora of sophisticated and highly abstract mental models for chemical bonding, and this study sought to investigate if there are preferred mental models for the concept of covalent bonding for secondary, undergraduate, and graduate chemistry learners. In particular, it was of interest to see whether exposure to increasingly sophisticated mental models at different points in a chemistry education showed up in patterns of preference and use of models in interpreting common physical properties and phenomena. The study revealed that, despite evidencing expertise in a number of highly complex and mathematically sophisticated mental models, tertiary students, including graduates (MSc and PhD), show a strong preference for simple realistic mental models. Furthermore, the students struggled to use their mental models to explain the physical properties of covalently bonded substances. 相似文献
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The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research study involving students enrolled in different types of organic chemistry course sections at our university. Our analysis led to the identification of four distinct mental models, some of which resembled scientific models of acids and acid strength. However, the distinct models are better characterized as synthetic models that combined assumptions from one or more scientific models with intuitive beliefs about factors that determine the properties of chemical substances. For many students in our sample, mental models served more as tools for heuristic decision‐making based on intuitively appealing, but many times mistaken, concept associations rather than as cognitive tools to generate explanations. Although many research participants used a single general mental model to complete all of the interview tasks, the presence of specific problem features or changes in the nature of the task (e.g., prediction vs. explanation) prompted several students to change their mental model or to add a different mental representation. Our study indicates that properly diversifying and sequencing the types of academic tasks in which students are asked to participate could better foster meaningful learning as different types of cognitive resources may be activated by different students, and thus shared, analyzed, and discussed. © 2011 Wiley Periodicals, Inc., Inc. J Res Sci Teach 48: 396–413, 2011 相似文献
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Anna Bergqvist Michal Drechsler Shu-Nu Chang Rundgren 《International Journal of Science Education》2016,38(2):298-318
Researchers have shown a growing interest in science teachers’ professional knowledge in recent decades. The article focuses on how chemistry teachers impart chemical bonding, one of the most important topics covered in upper secondary school chemistry courses. Chemical bonding is primarily taught using models, which are key for understanding science. However, many studies have determined that the use of models in science education can contribute to students’ difficulties understanding the topic, and that students generally find chemical bonding a challenging topic. The aim of this study is to investigate teachers’ knowledge of teaching chemical bonding. The study focuses on three essential components of pedagogical content knowledge (PCK): (1) the students’ understanding, (2) representations, and (3) instructional strategies. We analyzed lesson plans about chemical bonding generated by 10 chemistry teachers with whom we also conducted semi-structured interviews about their teaching. Our results revealed that the teachers were generally unaware of how the representations of models they used affected student comprehension. The teachers had trouble specifying students’ difficulties in understanding. Moreover, most of the instructional strategies described were generic and insufficient for promoting student understanding. Additionally, the teachers’ rationale for choosing a specific representation or activity was seldom directed at addressing students’ understanding. Our results indicate that both PCK components require improvement, and suggest that the two components should be connected. Implications for the professional development of pre-service and in-service teachers are discussed. 相似文献
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The purpose of this study was to investigate students' mental models of chemical equilibrium using dynamic science assessments. Research in chemical education has shown that students at various levels have misconceptions about chemical equilibrium. According to Chi's theory of conceptual change, the concept of chemical equilibrium has constraint‐based features (e.g., random, simultaneous, uniform activities) that might prevent students from deeply understanding the nature of the concept of chemical equilibrium. In this study, we examined how students learned and constructed their mental models of chemical equilibrium in a cognitive apprenticeship context. Thirty 10th‐grade students participated in the study: 10 in a control group and 20 in a treatment group. Both groups were presented with a series of hands‐on chemical experiments. The students in the treatment group were instructed based on the main features of cognitive apprenticeship (CA), such as coaching, modeling, scaffolding, articulation, reflection, and exploration. However, the students in the control group (non‐CA group) learned from the tutor without explicit CA support. The results revealed that the CA group significantly outperformed the non‐CA group. The students in the CA group were capable of constructing the mental models of chemical equilibrium—including dynamic, random activities of molecules and interactions between molecules in the microworld—whereas the students in the non‐CA group failed to construct similar correct mental models of chemical equilibrium. The study focuses on the process of constructing mental models, on dynamic changes, and on the actions of students (such as self‐monitoring/self‐correction) who are learning the concept of chemical equilibrium. Also, we discuss the implications for science education. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 688–712, 2002 相似文献
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Chemical bonding is one of the key and basic concepts in chemistry. The learning of many of the concepts taught in chemistry, in both secondary schools as well as in the colleges, is dependent upon understanding fundamental ideas related to chemical bonding. Nevertheless, the concept is perceived by teachers, as well as by learners, as difficult, with teaching commonly leading to students developing misconceptions. Many of these misconceptions result from over‐simplified models used in text books, by the use of traditional pedagogy that presents a rather limited and sometimes incorrect picture of the issues related to chemical bonding and by assessments of students' achievement that influence the way the topic is taught. In addition, there are discrepancies between scientists regarding key definitions in the topic and the most appropriate models to teach it. In particular, teaching models that are intended to have transitional epistemological value in introducing abstract ideas are often instead understood by students as accounts of ontological reality. In this review paper we provide science educators, curricula developers and pre‐service and in‐service professional development providers an up‐to‐date picture regarding research and developments in teaching about chemical bonding. We review the external and internal variables that might lead to misconceptions and the problematic issue of using limited teaching/learning models. Finally, we review the approaches to teaching the concept that might overcome some of these misconceptions. 相似文献
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化学键与分子间作用力是高中化学的重要知识点,为使学生深入理解,牢固掌握化学键及分子间作用力知识,并灵活应用于解题中,教师应结合学生实际,做好相关习题的汇总,组织学生开展习题教学活动,为学生认真剖析不同习题类型的解题思路,使其更好地把握不同化学键以及分子间作用力的规律,指引其更好地解题.文章结合相关习题,对高中化学键与分... 相似文献
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Learners' Mental Models of Chemical Bonding 总被引：1，自引：0，他引：1
The research reported in this inquiry consisted of a study involving two each of Year-12, undergraduate and postgraduate Australian students. The learners' mental models for chemical bonding were elicited using semi-structured interviews comprising a three-phase interview protocol. Each learner was presented with samples of metallic, ionic and covalent substances, and asked to describe the bonding in the substance. Second, they were shown prompts in the form of Interviews-About-Events (IAE) focus cards depicting events that involved the use of models of chemical bonding. Finally, each was shown prompts in the form of focus cards derived from curriculum material that showed ways in which the bonding in specific metallic, ionic and covalent substances had been depicted. Students' responses revealed that learners across all three academic levels prefer simple, realistic mental models for chemical bonding. 相似文献
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Assessing high school chemistry students’ modeling sub-skills in a computerized molecular modeling learning environment 总被引：1，自引：0，他引：1
Much knowledge in chemistry exists at a molecular level, inaccessible to direct perception. Chemistry instruction should therefore
include multiple visual representations, such as molecular models and symbols. This study describes the implementation and
assessment of a learning unit designed for 12th grade chemistry honors students. The organic chemistry part of the unit was
taught in a Computerized Molecular Modeling (CMM) learning environment, where students explored daily life organic molecules
through assignments and two CMM software packages. The research objective was to investigate the effect of the CMM learning
unit on students’ modeling skill and sub-skills, including (a) drawing and transferring between a molecular formula, a structural
formula, and a model, and (b) transferring between symbols/models and microscopic, macroscopic, and process chemistry understanding
levels. About 600 12th grade chemistry students who studied the CMM unit responded to a reflection questionnaire, and were
assessed for their modeling skill and sub-skills via pre- and post-case-based questionnaires. Students indicated that the
CMM environment contributed to their understanding of the four chemistry understanding levels and the links among them. Students
significantly improved their scores in the five modeling sub-skills. As the complexity of the modeling assignments increased,
the number of students who responded correctly and fully decreased. We present a hierarchy of modeling sub-skills, starting
with understanding symbols and molecular structures, and ending with mastering the four chemistry understanding levels. We
recommend that chemical educators use case-based tools to assess their students’ modeling skill and validate the initial hierarchy
with a different set of questions. 相似文献
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A longitudinal study of 250 students following the Salters Advanced Chemistry (SAC) course probed a range of chemical ideas including the exothermicity of bond formation and the development of thinking about covalent, ionic and intermolecular bonds. Students responded to the same diagnostic questions on three occasions: at the start, after eight months and sixteen months of a twenty-month course. At the start, many students demonstrated misunderstandings about these chemical ideas, but in general their understanding improved as the course progressed. By the end of the study, about half knew that bond making is exothermic. Initially, few described covalent bonds accurately or understood hydrogen bonding. A majority gave responses at the final survey which were in line with ideas and language a chemist may use. Students attributed changes to the use of context-based materials including a drip-feed approach which allowed their understanding to develop over time. However, some aspects of chemical bonding, including ionic bonding and intermolecular bonds other than hydrogen bonds remained problematic for students despite explicit teaching. The findings have implications for post-16 chemistry teaching, suggesting that a review of teaching strategies is needed in some areas. 相似文献
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Understanding bonding is fundamental to success in chemistry. A number of alternative conceptions related to chemical bonding have been reported in the literature. Research suggests that many alternative conceptions held by chemistry students result from previous teaching; if teachers are explicit in the use of representations and explain their content-specific forms and functions, this might be avoided. The development of an understanding of and ability to use multiple representations is crucial to students’ understanding of chemical bonding. This paper draws on data from a larger study involving two Year 11 chemistry classes (n = 27, n = 22). It explores the contribution of explicit instruction about multiple representations to students’ understanding and representation of chemical bonding. The instructional strategies were documented using audio-recordings and the teacher-researcher’s reflection journal. Pre-test–post-test comparisons showed an improvement in conceptual understanding and representational competence. Analysis of the students’ texts provided further evidence of the students’ ability to use multiple representations to explain macroscopic phenomena on the molecular level. The findings suggest that explicit instruction about representational form and function contributes to the enhancement of representational competence and conceptual understanding of bonding in chemistry. However, the scaffolding strategies employed by the teacher play an important role in the learning process. This research has implications for professional development enhancing teachers’ approaches to these aspects of instruction around chemical bonding. 相似文献
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Modern chemistry concepts have the particulate nature of matter at their core. Chemists explain most phenomena in terms of atomic and molecular models. The lack of understanding of chemistry concepts may be linked to the students' inability to build complete mental models that visualize particulate behavior. With computer animation technology, dynamic and three-dimensional presentations are possible. This study explores the effect of computer animations depicting the particulate nature of matter on college students' mental models of the chemical phenomena. A Particulate Nature of Matter Evaluation Test (PNMET) instrument was used to determine the nature of the students' visualizations and, therefore, their comprehension of the chemical concept studied. Animations were used in two treatment situations: (a) as a supplement in large-group lectures, and (b) as both the lecture supplement and an assigned individual activity in a computer laboratory. These two experimental treatments were compared to a control group. Both treatment groups received significantly higher conceptual understanding scores on the PNMET than did the control group. This increased understanding may be due to the superiority of the formation of more expertlike, dynamic mental models of particle behavior in these chemical processes. 相似文献
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Submicrorepresentations (SMRs) are a powerful tool for identifying misconceptions of chemical concepts and for generating proper mental models of chemical phenomena in students’ long‐term memory during chemical education. The main purpose of the study was to determine which independent variables (gender, formal reasoning abilities, visualization abilities, and intrinsic motivation for learning chemistry) have the maximum influence on students’ reading and drawing SMRs. A total of 386 secondary school students (aged 16.3 years) participated in the study. The instruments used in the study were: test of Chemical Knowledge, Test of Logical Thinking, two tests of visualization abilities Patterns and Rotations, and questionnaire on Intrinsic Motivation for Learning Science. The results show moderate, but statistically significant correlations between students’ intrinsic motivation, formal reasoning abilities and chemical knowledge at submicroscopic level based on reading and drawing SMRs. Visualization abilities are not statistically significantly correlated with students’ success on items that comprise reading or drawing SMRs. It can be also concluded that there is a statistically significant difference between male and female students in solving problems that include reading or drawing SMRs. Based on these statistical results and content analysis of the sample problems, several educational strategies can be implemented for students to develop adequate mental models of chemical concepts on all three levels of representations. 相似文献
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High-School Chemistry Students' Performance and Gender Differences in a Computerized Molecular Modeling Learning Environment 总被引：1，自引：1，他引：0
Computerized molecular modeling (CMM) contributes to the development of visualization skills via vivid animation of three dimensional representations. Its power to illustrate and explore phenomena in chemistry teaching stems from the convenience and simplicity of building molecules of any size and color in a number of presentation styles. A new CMM-based learning environment for teaching and learning chemistry in Israeli high schools has been designed and implemented. Three tenth grade experimental classes used this discovery CMM approach, while two other classes, who studied the same topic in the customary approach, served as a control group. We investigated the effects of using molecular modeling on students' spatial ability, understanding of new concepts related to geometric and symbolic representations and students' perception of the model concept. Each variable was examined for gender differences. Students of the experimental group performed better than control group students in all three performance aspects. Experimental group students scored higher than the control group students in the achievement test on structure and bonding. Students' spatial ability improved in both groups, but students from the experimental group scored higher. For the average students in the two groups the improvement in all three spatial ability sub-tests —paper folding, card rotation, and cube comparison—was significantly higher for the experimental group. Experimental group students gained better insight into the model concept than the control group and could explain more phenomena with the aid of a variety of models. Hence, CMM helps in particular to improve the examined cognitive aspects of the average student population. In most of the achievement and spatial ability tests no significant differences between the genders were found, but in some aspects of model perception and verbal argumentation differences still exist. Experimental group females improved their model perception more than the control group females in understanding ways to create models and in the role of models as mental structures and prediction tools. Teachers' and students' feedback on the CMM learning environment was found to be positive, as it helped them understand concepts in molecular geometry and bonding. The results of this study suggest that teaching/learning of topics in chemistry that are related to three dimensional structures can be improved by using a discovery approach in a computerized learning environment. 相似文献
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This article initially outlines a procedure used to develop a written diagnostic instrument to identify grade-11 and -12 students' misconceptions and misunderstandings of the chemistry topic covalent bonding and structure. The content to be taught was carefully defined through a concept map and propositional statements. Following instruction, student understanding of the topic was identified from interviews, student-drawn concept maps, and free-response questions. These data were used to produce 15 two-tier multiple-choice items where the first tier examined content knowledge and the second examined understanding of that knowledge in six conceptual areas, namely, bond polarity, molecular shape, polarity of molecules, lattices, intermolecular forces, and the octet rule. The diagnostic instrument was administered to a total of 243 grade-11 and -12 chemistry students and has a Cronbach alpha reliability of 0.73. Item difficulties ranged from 0.13 to 0.60; discrimination values ranged from 0.32 to 0.65. Each item was analyzed to ascertain student understanding of and identify misconceptions related to the concepts and propositional statements underlying covalent bonding and structure. 相似文献
16.
离子性盐类溶解性的问题是无机化学教学中的一个难点,一般运用离子极化和化学键理论予以定性的解释,过于粗浅;运用化学热力学的方法就离子性盐类溶解性的问题进行分析研究,从宏观上定量的或半定量的分析讨论,可以引导学生将宏观的热力学数据与微观的结构因素联系起来,从而使学生对离子性盐类溶解性的问题有比较深刻的理解,其效果远比只从微观所作的定性解释更能令人信服。 相似文献
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Marilyne Stains 《International Journal of Science Education》2013,35(5):643-661
We applied a mixed‐method research design to investigate the patterns of reasoning used by novice undergraduate chemistry students to classify chemical substances as elements, compounds, or mixtures based on their particulate representations. We were interested in the identification of the representational features that students use to build a classification system, and in the characterization of the thinking processes that they follow to group substances in different classes. Students in our study used structural and chemical composition features to classify chemical substances into elements, compounds, and mixtures. Many of the students’ classification errors resulted from strong mental associations between concepts (e.g., atom–element, molecule–compound) or from lack of conceptual differentiation (e.g., compound–mixture). Strong concept associations led novice students to reduce the number of relevant features used to differentiate between substances, while the inability to discriminate between two concepts (conceptual undifferentiation) led them to pay too much attention to irrelevant features during the classification tasks. Comparisons of the responses to classification tasks of students with different levels of expertise in chemistry indicate that some of these naïve patterns of reasoning may be strengthened by, rather than weakened by, training in the discipline. 相似文献
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Keith S. Taber Georgios Tsaparlis Canan Nakiboğlu 《International Journal of Science Education》2013,35(18):2843-2873
Previous research has reported that students commonly develop alternative conceptions in the core topic of chemical bonding. Research in England has reported that students there commonly demonstrate an alternative ‘molecular’ conceptual framework for thinking about ionic bonding: in terms of the formation of molecule-like ions pairs through electron transfer, which are internally bonded, but not bonded to other ions. The present study reports the use of translated versions of a diagnostic instrument to elicit the conceptions of bonding in NaCl (commonly used as the teaching example of an ionic compound) from two samples of students setting out on university courses in Greece and Turkey. The study reports that students in these two contexts displayed high levels of support for statements based upon the alternative conceptual framework identified in the English context. Students commonly develop similar alternative conceptions of ionic bonding in these three different educational contexts. The study also found some quite large differences in the specific response patterns across these three contexts, some of which could reflect specific features of the different curriculum contexts. The study reinforces the cross-national nature of the challenge of effectively teaching the abstract models of chemistry at the submicroscopic level. It also provides intriguing suggestions that a close study of the interactions between specific curriculum contexts and specific patterns in students' thinking offers much potential for identifying particular aspects of subject pedagogy that either support or impede the learning of accepted scientific models. 相似文献
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Velázquez-Marcano Alexandra Williamson Vickie M. Ashkenazi Guy Tasker Roy Williamson Kenneth C. 《Journal of Science Education and Technology》2004,13(3):315-323
Different visualization techniques have been used for teaching chemistry concepts. Previous studies have shown that when molecular animations and video demonstrations are used, students seem to better correlate all three levels of representation: macroscopic, submicroscopic, and symbolic. This thinking process allows the students to improve their conceptual understanding and ability to create dynamic mental models. In this study, general chemistry students viewed three experiments involving dynamic fluid equilibrium in a graphic design, a video demonstration, and a molecular animation. The study investigated whether video demonstrations or particulate animations helped the students' conceptual understanding, and if the order of visualizations (video or animation first) produced any differences. Students showed improvement after each visualization. Surprisingly, there was significant improvement in responses between the first and second visualization. This work shows the importance of combining both types of visualizations, but it does not indicate a preference toward a specific order. 相似文献
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Jing‐Wen Lin 《International Journal of Science Education》2013,35(12):1617-1646
The aim of this study is to compare the characteristics and sources of students’ mental models of acids and bases with a teacher’s anticipations and, based on this comparison, to explore some possible explanations why motivated students might fail to learn from a subject‐knowledgeable chemistry teacher. The study involves a chemistry teacher and her 38 ninth graders and focuses on the mental models of three high achievers and three low achievers who were interviewed in depth. Four students’ mental models of acid and base are identified. The mental models and sources of students’ conceptions of acids and bases that influenced the high achievers are compared to those of the low achievers. We find that the teacher in the study made accurate anticipations of her students’ mental models in the case of the high achievers but inaccurate anticipations of the low‐achievers’ mental models and the diverse sources influencing their mental models. In addition, the teacher incorrectly attributed the poor achievement of the low‐achieving students to their intuition and underestimated the effects of her teaching on the achievement of these students. As a result, the teacher’s instruction reinforced the low‐achievers’ incorrect mental models. Finally, the different approaches for teaching students with different achievements are emphasized according to the empirical data in this study. 相似文献