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1.
Many students have difficulty learning symbolic and molecular representations of chemistry. This study investigated how students developed an understanding of chemical representations with the aid of a computer‐based visualizing tool, eChem, that allowed them to build molecular models and view multiple representations simultaneously. Multiple sources of data were collected with the participation of 71 eleventh graders at a small public high school over a 6‐week period. The results of pre‐ and posttests showed that students' understanding of chemical representations improved substantially (p < .001, effect size = 2.68‐. The analysis of video recordings revealed that several features in eChem helped students construct models and translate representations. Students who were highly engaged in discussions while using eChem made referential linkages between visual and conceptual aspects of representations. This in turn may have deepened their understanding of chemical representations and concepts. The findings also suggest that computerized models can serve as a vehicle for students to generate mental images. Finally, students demonstrated their preferences of certain types of representations and did not use all types of three‐dimensional models interchangeably. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 821–842, 2001  相似文献   

2.
A new learning unit in chemistry, Case-based Computerized Laboratories (CCL) and Computerized Molecular Modeling (CMM) was developed at the Technion. The CCL and CMM curriculum integrates computerized desktop experiments and molecular modeling with an emphasis on scientific inquiry and case studies. Our research aimed at investigating the effect of the CCL and CMM learning environment on students’ higher-order thinking skills of question posing, inquiry, and modeling. The experimental group included 614 honors 12th grade chemistry students from high schools in Israel who studied according to this learning unit. The comparison group consisted of 155 12th grade chemistry honors students who studied other chemistry programs. Pre- and post-tests questionnaires were used to assess students’ higher-order thinking skills. Students’ responses were analyzed using content analysis rubrics and their statistical analysis. Our findings indicated that the scores of the experimental group students improved significantly in question posing, inquiry and modeling skills from the pre-test to the post-test. The net gain scores of the experimental group students were significantly higher than those of their comparison peers in all three examined skills. In modeling skills, experimental group students significantly improved their achievements in making the transfer from 3D models to structural formulae, but only about half of them were able to transfer from formulae to 3D models. By presenting a case-based chemistry assessment tool and content analysis of students’ responses in this paper, we enable teachers and educators to analyze their students’ higher-order thinking skills both qualitatively and quantitatively.  相似文献   

3.
The present article discusses the design and impact of computer‐based visualization tools for supporting student learning and representational competence in science. Specifically, learning outcomes and student representation use are compared between eight secondary classrooms utilizing The Connected Chemistry Curriculum and eight secondary chemistry using lecture‐based methods. Results from the quasi‐experimental intervention indicate that the curriculum and accompanying visualization tool yield only small to modest gains in student achievement on summative assessments. Analysis of student representation use on pre‐ and post‐assessments, however, indicate the students in Connected Chemistry classrooms are significantly more likely to use submicroscopic representations of chemical systems that are consistent with teacher and expert representation use. The affordances of visualization tools in inquiry activities to improve students' representational competence and conceptual understanding of content in the science classroom are discussed. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 1137–1158, 2011  相似文献   

4.
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   

5.
Assessing the credibility of evidence in complex, socio‐scientific problems is of paramount importance. However, there is little discussion in the science education literature on this topic and on how students can be supported in developing such skills. In this article, we describe an instructional design framework, which we call the Credibility Assessment Framework, to scaffold high school students' collaborative construction of evidence‐based decisions and their assessment of the credibility of evidence. The framework was employed for the design of a web‐based reflective inquiry environment on a socio‐scientific issue, and was enacted with 11th grade students. The article describes the components of the Credibility Assessment Framework and provides the details and results of an empirical study illustrating this framework in practice. The results are presented in the form of a case study of how 11th grade students investigated and evaluated scientific data relating to the cultivation of genetically modified plants. Multiple kinds of data were collected, including pre‐ and post‐tests of students' conceptual understanding and their skills in assessing the credibility of evidence, and videotapes of students' collaborative inquiry sessions. The analysis of the pre‐ and post‐tests on students' conceptual understanding of Biotechnology and their skills in assessing the credibility of evidence revealed statistically significant learning gains. Students' work in task‐related artifacts and the analysis of two groups' videotaped discussions showed that students became sensitive to credibility criteria, questioned the sources of data and correctly identified sources of low, moderate, and high credibility. Implications for designers and educators regarding the application of this framework are discussed. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 711–744, 2011  相似文献   

6.
Chemistry is commonly portrayed at three different levels of representation – macroscopic, submicroscopic and symbolic – that combine to enrich the explanations of chemical concepts. In this article, we examine the use of submicroscopic and symbolic representations in chemical explanations and ascertain how they provide meaning. Of specific interest is the development of students' levels of understanding, conceived as instrumental (knowing how) and relational (knowing why) understanding, as a result of regular Grade 11 chemistry lessons using analogical, anthropomorphic, relational, problem‐based, and model‐based explanations. Examples of both teachers' and students' dialogue are used to illustrate how submicroscopic and symbolic representations are manifested in their explanations of observed chemical phenomena. The data in this research indicated that effective learning at a relational level of understanding requires simultaneous use of submicroscopic and symbolic representations in chemical explanations. Representations are used to help the learner learn; however, the research findings showed that students do not always understand the role of the representation that is assumed by the teacher.  相似文献   

7.
Inquiry instruction often neglects graphing. It gives students few opportunities to develop the knowledge and skills necessary to take advantage of graphs, and which are called for by current science education standards. Yet, it is not well known how to support graphing skills, particularly within middle school science inquiry contexts. Using qualitative graphs is a promising, but underexplored approach. In contrast to quantitative graphs, which can lead students to focus too narrowly on the mechanics of plotting points, qualitative graphs can encourage students to relate graphical representations to their conceptual meaning. Guided by the Knowledge Integration framework, which recognizes and guides students in integrating their diverse ideas about science, we incorporated qualitative graphing activities into a seventh grade web-based inquiry unit about cell division and cancer treatment. In Study 1, we characterized the kinds of graphs students generated in terms of their integration of graphical and scientific knowledge. We also found that students (n = 30) using the unit made significant learning gains based on their pretest to post-test scores. In Study 2, we compared students' performance in two versions of the same unit: One that had students construct, and second that had them critique qualitative graphs. Results showed that both activities had distinct benefits, and improved students' (n = 117) integrated understanding of graphs and science. Specifically, critiquing graphs helped students improve their scientific explanations within the unit, while constructing graphs led students to link key science ideas within both their in-unit and post-unit explanations. We discuss the relative affordances and constraints of critique and construction activities, and observe students' common misunderstandings of graphs. In all, this study offers a critical exploration of how to design instruction that simultaneously supports students' science and graph understanding within complex inquiry contexts.  相似文献   

8.
This study explores how students' learning styles influence their learning while solving complex problems when a case‐based e‐learning environment is implemented in a conventional lecture‐oriented classroom. Seventy students from an anaesthesiology class at a dental school participated in this study over a 3‐week period. Five learning‐outcome tests and two course‐satisfaction surveys were implemented during the case‐based instruction using a blended approach (online and face‐to‐face). The results of one‐way ANOVAs with repeated measures revealed that the four learning styles (active–reflective, sensing–intuitive, visual–verbal, sequential–global) did not influence students' learning experience and learning outcomes during the implementation of case‐based e‐learning. However, the pattern of the students' performance graph and further analysis with a liberal approach implied that the active–reflective learning style may influence learning outcomes slightly at an earlier time during the case‐based learning implementation; however, as time passed, this learning style no longer influenced their learning at all. Thus, learning styles may not be considered important or may be considered only during the early stages of instructional implementation in order to facilitate the students' transition to the new case‐based learning environment. It is more efficient to encourage students to adapt to different learning environments than to design adaptive systems in order to embrace diverse learning styles.  相似文献   

9.
In science education, representations are necessary inter alia for the understanding of relationships between structures and systems. However, several studies have identified difficulties of students when working with representations. In the present study, we investigated students' responses (regarding their preference, test performance, mental load (ML), and stress) toward two kinds of representations: symbolic representations, which only use abstract symbols, versus combined symbolic–textual representations, which additionally comprise textual elements. Therefore, students were randomly assigned to one of two treatment groups: one group worked on test tasks accompanied by symbolic representations, and the others worked on the same tasks, but with symbolic–textual representations. Thereafter, the students' test performance and ML were assessed. The level of perceived stress and the salivary cortisol concentration were measured before and after the test and again a few minutes later. Additionally, heart rate variability parameters were assessed continuously. We found a strong preference of the test version with symbolic representations. Additionally, the students showed better test performance and lower ML when they worked with symbolic representations. However, the level of perceived stress was comparable between both groups and there was no strong physiological stress response: The cortisol concentration decreased in both groups and the heart rate was relatively similar. However, during the second half of the test, we observed a significantly higher ratio between low and high heartbeat frequencies in the group with symbolic–textual representations and we found an indirect influence of the kind of representation on test performance through its effect on ML. The poorer test performance and higher ML in connection with symbolic–textual representations confirm previous studies, which found that symbolic–textual representations pose major problems for students. Thus, teachers should enable students to understand symbolic–textual representations and consider carefully whether they can use symbolic representations instead, especially when they teach complex content.  相似文献   

10.
Posing questions about an article might improve one’s knowledge—a cognitive function, or monitor one’s thought processes—a metacognitive function. This study focuses on guided question posing while using a metacognitive strategy by 12th grade honors chemistry students. We investigated the ways by which the metacognitive strategy affected students’ skills to pose complex questions and to analyze them according to a specially designed taxonomy. Our learning unit, Case-based computerized laboratories, emphasizes learning through chemical case studies, accompanied by tasks, that call for posing questions to which the answer cannot be found in the text. Teachers equipped their students with a metacognitive strategy for assessing the quality of their own questions and characterizing them according to a three-component taxonomy: content, thinking level, and chemistry understanding levels. The participants were 793 experimental and 138 comparison chemistry students. Research instruments included interviews and case-based-questionnaires. Interviews with students revealed that using the metacognitive strategy the students had been taught, they were capable of analyzing the questions they generated with the taxonomy. The questionnaires showed that students significantly improved their question posing skill, as well as the complexity level of the questions they posed. A significant difference was found in favor of the experimental group students. Stimulating students to generate complex questions with a metacognitive strategy in mind enabled them to be aware of their own cognitive process and to self-regulate it with respect to the learning task.  相似文献   

11.
The goal of this study was to investigate whether integrating a website into chemistry teaching influences 10th‐grade students' perceptions of the classroom learning environment, their attitudes regarding the relevance of chemistry, and their understanding of the concept of chemical bonding. Two groups participated in this study: an experimental group and a comparison group. The main study was conducted during the academic year 2005. The teachers in the experimental group were asked to implement four relevant activities from the website that was developed, all dealing with the concept of chemical bonding. Quantitative tools of the study included: A Chemistry Classroom Web‐Based Learning Environment Inventory to assess students' perceptions regarding the relevance of chemistry to their life and attitude towards chemistry studies, a feedback questionnaire that examined the students' response after performing the website activities, and an achievement test that assessed their knowledge and understanding of the concept of chemical bonding. We found that the experimental group outperformed the comparison group significantly in most of the research categories. This led us to conclude that the web‐based learning environment has potential to enhance the comprehension of chemistry concepts, students' attitudes and interests and to increase students' awareness regarding the relevant aspects of chemistry to daily life.  相似文献   

12.
The literature provides confounding information with regard to questions about whether students in high school can engage in meaningful argumentation about socio‐scientific issues and whether this process improves their conceptual understanding of science. The purpose of this research was to explore the impact of classroom‐based argumentation on high school students' argumentation skills, informal reasoning, and conceptual understanding of genetics. The research was conducted as a case study in one school with an embedded quasi‐experimental design with two Grade 10 classes (n = 46) forming the argumentation group and two Grade 10 classes (n = 46) forming the comparison group. The teacher of the argumentation group participated in professional learning and explicitly taught argumentation skills to the students in his classes during one, 50‐minute lesson and involved them in whole‐class argumentation about socio‐scientific issues in a further two lessons. Data were generated through a detailed, written pre‐ and post‐instruction student survey. The findings showed that the argumentation group, but not the comparison group, improved significantly in the complexity and quality of their arguments and gave more explanations showing rational informal reasoning. Both groups improved significantly in their genetics understanding, but the improvement of the argumentation group was significantly better than the comparison group. The importance of the findings are that after only a short intervention of three lessons, improvements in the structure and complexity of students' arguments, the degree of rational informal reasoning, and students' conceptual understanding of science can occur. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 952–977, 2010  相似文献   

13.
Matriculation 2000 was a 5‐year project aimed at moving from the nationwide traditional examination system in Israel to a school‐based alternative embedded assessment. Encompassing 22 high schools from various communities in the country, the Project aimed at fostering deep understanding, higher‐order thinking skills, and students' engagement in learning through alternative teaching and embedded assessment methods. This article describes research conducted during the fifth year of the Project at 2 experimental and 2 control schools. The research objective was to investigate students' learning outcomes in chemistry and biology in the Matriculation 2000 Project. The assumption was that alternative embedded assessment has some effect on students' performance. The experimental students scored significantly higher than their control group peers on low‐level assignments and more so on assignments that required higher‐order thinking skills. The findings indicate that given adequate support and teachers' consent and collaboration, schools can transfer from nationwide or statewide standardized testing to school‐based alter‐native embedded assessment. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 34–52, 2003  相似文献   

14.
This article explores the conceptual change of students in Grades 10 and 12 in three Australian senior high schools when the teachers included computer multimedia to a greater or lesser extent in their teaching of a genetics course. The study, underpinned by a multidimensional conceptual‐change framework, used an interpretive approach and a case‐based design with multiple data collection methods. Over 4–8 weeks, the students learned genetics in classroom lessons that included BioLogica activities, which feature multiple representations. Results of the online tests and interview tasks revealed that most students improved their understanding of genetics as evidenced in the development of genetics reasoning. However, using Thorley's (1990) status analysis categories, a cross‐case analysis of the gene conceptions of 9 of the 26 students interviewed indicated that only 4 students' postinstructional conceptions were intelligible–plausible–fruitful. Students' conceptual change was consistent with classroom teaching and learning. Findings suggested that multiple representations supported conceptual understanding of genetics but not in all students. It was also shown that status can be a viable hallmark enabling researchers to identify students' conceptual change that would otherwise be less accessible. Thorley's method for analyzing conceptual status is discussed. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 205–235, 2007  相似文献   

15.
Although many studies have revealed the importance of study skills for students' first‐year performance and college retention, the extent of the impact of study skills preparation on students' academic achievement is less clear. This paper explores the impact of pre‐university study skills preparation on students' first‐year study experiences, academic achievement and persistence. The setting for this study is a large law school in the Netherlands which attracts students from more than 100 schools for secondary education. The results show that the perceived study skills preparation concerning time management and learning skills does have a positive impact on college students' first‐year study behaviour and academic achievement. However, the study also shows that the impact of perceived college preparation is far less important for college retention than other factors such as satisfaction about the chosen degree programme and tutorial attendance.  相似文献   

16.
Over the past 20 years, researchers have begun to examine data from asynchronous computer‐mediated student discussions in courses. Some results have shown students to demonstrate lower or mid‐level thinking skills, while others suggest students routinely demonstrate higher‐order thinking skills. The authors investigated the relationship between scaffold types and the level of students' thinking skill performance, learning achievement and attitudes, in a two‐by‐two factorial, quasi‐experimental study. Participants included 216 undergraduate preservice K‐12 teachers who were presented with one of four versions of an asynchronous discussion board assignment. Resulting discussion interactions were evaluated for demonstration of low‐, mid‐ and higher‐order thinking skills. Findings revealed students who were given a scaffold demonstrated higher‐level thinking skills more frequently than did students who received no scaffold. No significant differences in learning achievement associated with test performance were found in test results. The treatment variables did significantly affect effect survey ratings associated with students' attitudes.  相似文献   

17.
ABSTRACT

Context-based learning (CBL), promoting students' scientific text comprehension, and fostering metacognitive skills, plays an important role in science education. Our study involves CBL through comprehension and analysis of adapted scientific articles. We developed a module which integrates metacognitive prompts for guiding students to monitor their understanding and improve their scientific text comprehension. We investigated the effect of these metacognitive prompts on scientific text comprehension as part of CBL in chemistry. About 670 high school chemistry students were randomly divided into three groups exposed to high- and low-intensity CBL. One of the high-intensity groups was also exposed to metacognitive prompts. Research tools included pre- and post-questionnaires aimed at measuring students' conceptual chemistry understanding and metacognitive knowledge in the context of reading strategies, before and after exposure to the CBL. Chemistry understanding was reflected by students' ability to identify the main subject of the adapted article and by explaining concepts both textually and visually. We found that high-intensity CBL combined with metacognitive prompts improved students' chemistry understanding of the adapted scientific articles and the ability to regulate their learning. Our study establishes that reading context-based adapted scientific articles advances students' conceptual chemistry understanding. These gains are strongly amplified by domain-specific metacognitive prompts.  相似文献   

18.
This article examines the strategies that can be used to enhance students' understanding of how subjects link together and whether cross‐curricular approaches, through a gallery project, have any real impact on students' understanding of the links between subjects. A substantial part of this article, however, describes the methodological aspect of the project. A phenomenological case study approach was used in order to engage fully with individual students' learning experiences. It was found that the students who were involved directly with the study felt that the links between subjects had more relevance to their learning when the teacher made such links explicit. They were unaware of the relevance of many cross‐curricular links made in lessons, but the study indicated that cross‐curricular learning can enable students to transfer skills and knowledge in order to understand concepts more fully.  相似文献   

19.
One hundred and thirty‐three preclinical medical students participated in 24 focus groups over the period 2007–2009 at Durham University. Focus groups were conducted to ascertain whether or not medical students found body painting anatomical structures to be an educationally beneficial learning activity. Data were analyzed using a grounded theory approach. Five principal themes emerged: (1) body painting as a fun learning activity, (2) body painting promoting retention of knowledge, (3) factors contributing to the memorability of body painting, (4) removal from comfort zone, and (5) the impact of body painting on students' future clinical practice. Students perceive body painting to be a fun learning activity, which aids their retention of the anatomical knowledge acquired during the session. Sensory factors, such as visual stimuli, especially color, and the tactile nature of the activity, promote recall. Students' preference for painting a peer or being painted is often dependent upon their learning style, but there are educational benefits for both roles. The moderate amounts of undressing involved encouraging students to consider issues surrounding body image; this informs their attitudes towards future patients. Body painting is a useful adjunct to traditional anatomy and clinical skills teaching. The fun element involved in the delivery of this teaching defuses the often formal academic context, which in turn promotes a positive learning environment. Anat Sci Educ 3:33–38, 2010. © 2009 American Association of Anatomists.  相似文献   

20.
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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