Representational Classroom Practices that Contribute to Students’ Conceptual and Representational Understanding of Chemical Bonding

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.     

Effectiveness of multimedia‐based instruction that emphasizes molecular representations on students' understanding of chemical change

The present study makes use of the capabilities of computerized environments to enable simultaneous display of molecular representations that correspond to observations at the macroscopic level. This study questions the immediate and long‐term effects of using a multimedia instructional unit that integrates the macroscopic, symbolic, and molecular representations of chemical phenomena. Forty‐nine eighth graders received either multimedia‐based instruction that emphasized molecular representations (n = 16), or regular instruction (n = 33). Students who received multimedia‐based instruction that emphasized the molecular state of chemicals outperformed students from the regular instruction group in terms of the resulting test scores and the ease with which they could represent matter at the molecular level. However, results relating to the long‐term effects suggest that the effectiveness of a multimedia‐based environment can be improved if instruction includes additional prompting that requires students to attend to the correspondence between different representations of the same phenomena. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 317–337, 2004     

Chemical understanding and graphing skills in an honors case‐based computerized chemistry laboratory environment: The value of bidirectional visual and textual representations

The case‐based computerized laboratory (CCL) is a chemistry learning environment that integrates computerized experiments with emphasis on scientific inquiry and comprehension of case studies. The research objective was to investigate chemical understanding and graphing skills of high school honors students via bidirectional visual and textual representations in the CCL learning environment. The research population of our 3‐year study consisted of 857 chemistry 12th grade honors students from a variety of high schools in Israel. Pre‐ and postcase‐based questionnaires were used to assess students' graphing and chemical understanding–retention skills. We found that students in the CCL learning environment significantly improved their graphing skills and chemical understanding–retention in the post‐ with respect to the prequestionnaires. Comparing the experimental students to their non‐CCL control peers has shown that CCL students had an advantage in graphing skills. The CCL contribution was most noticeable for experimental students of relatively low academic level who benefit the most from the combination of visual and textual representations. Our findings emphasize the educational value of combining the case‐based method with computerized laboratories for enhancing students' chemistry understanding and graphing skills, and for developing their ability to bidirectionally transfer between textual and visual representations. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 219–250, 2008.     

The influence of textbooks on teachers’ knowledge of chemical bonding representations relative to students’ difficulties understanding

Background: Textbooks are integral tools for teachers’ lessons. Several researchers observed that school teachers rely heavily on textbooks as informational sources when planning lessons. Moreover, textbooks are an important resource for developing students’ knowledge as they contain various representations that influence students’ learning. However, several studies report that students have difficulties understanding models in general, and chemical bonding models in particular, and that students’ difficulties understanding chemical bonding are partly due to the way it is taught by teachers and presented in textbooks.

Purpose: This article aims to delineate the influence of textbooks on teachers’ selection and use of representations when teaching chemical bonding models and to show how this might cause students’ difficulties understanding.

Sample: Ten chemistry teachers from seven upper secondary schools located in Central Sweden volunteered to participate in this study.

Design and methods: Data from multiple sources were collected and analysed, including interviews with the 10 upper secondary school teachers, the teachers’ lesson plans, and the contents of the textbooks used by the teachers.

Results: The results revealed strong coherence between how chemical bonding models are presented in textbooks and by teachers, and thus depict that textbooks influence teachers’ selection and use of representations for their lessons. As discussed in the literature review, several of the selected representations were associated with alternative conceptions of, and difficulties understanding, chemical bonding among students.

Conclusions: The study highlights the need for filling the gap between research and teaching practices, focusing particularly on how representations of chemical bonding can lead to students’ difficulties understanding. The gap may be filled by developing teachers’ pedagogical content knowledge regarding chemical bonding and scientific models in general.     

The Relation between Students’ Epistemological Understanding of Computer Models and their Cognitive Processing on a Modelling Task

While many researchers in science education have argued that students’ epistemological understanding of models and of modelling processes would influence their cognitive processing on a modelling task, there has been little direct evidence for such an effect. Therefore, this study aimed to investigate the relation between students’ epistemological understanding of models and modelling and their cognitive processing (i.e., deep versus surface processing) on a modelling task. Twenty‐six students, working in dyads, were observed while working on a computer‐based modelling task in the domain of physics. Students’ epistemological understanding was assessed on four dimensions (i.e., nature of models, purposes of models, process of modelling, and evaluation of models). Students’ cognitive processes were assessed based on their verbal protocols, using a coding scheme to classify their types of reasoning. The outcomes confirmed the expected positive correlation between students’ level of epistemological understanding and their deep processing (r = 0.40, p = .04), and the negative correlation between level of epistemological understanding and surface processing (r = ?0.51, p = .008). From these results, we emphasise the necessity of considering epistemological understanding in research as well as in educational practice.     

Using Static and Dynamic Visuals to Represent Chemical Change at Molecular Level

The study examines the effectiveness of visually enhanced instruction that emphasizes molecular representations. Instructional conditions were specified in terms of the visual elaboration level (static and dynamic) and the presentation mode (whole class and individual). Fifty‐two eighth graders (age range 14–15 years) participated in one of the three instructional conditions (dynamic–individual, dynamic–whole class, and static–whole class) designed to improve molecular understanding on chemical change. The results indicated significantly higher performance for students who used dynamic visuals compared with those who used static visuals. Furthermore, students who used dynamic visuals on an individual basis were more consistent in their use of molecular representations compared with students who received whole‐class instruction with dynamic or static visuals. The results favour the use of dynamic visuals (preferably on an individual basis) over static visuals when presenting molecular representations. The results also imply that the effectiveness of instruction will improve if teachers challenge and question the inconsistencies and contradictions between verbal explanations and corresponding molecular representations     

Promoting Linguistically Diverse Students’ Short-Term and Long-Term Understanding of Chemical Phenomena Using Visualizations

Ensuring that all students, including English language learners (ELLs) who speak English as a second language, succeed in science is more challenging with a shift towards learning through language-intensive science practices suggested by the Next Generation Science Standards (NGSS). Interactive visualization technologies have the potential to support science learning for all students, including ELLs, by providing explicit representations of unobservable scientific systems. However, whether and how such technologies can be beneficial for these underserved students has not been sufficiently investigated. In this study, we examine the short-term and long-term effects of interactive visualizations in improving linguistically diverse eighth-grade students’ understanding of properties of matter and chemical reactions during inquiry instruction. The results show that after interacting with the visualizations, both ELLs and non-ELLs showed significant improvement in their understanding of the target concepts at the molecular level on both the immediate test and the delayed test (3 months after the study). In particular, aligned with the goals of the NGSS, all students, including ELLs, were able to demonstrate their understanding of how energy and matter are involved in chemistry through developing molecular models, critiquing models, and constructing scientific explanations. This study shows the potential benefits of using interactive visualizations during inquiry instruction as a resource to help all students, including ELLs who are traditionally underserved in mainstream classrooms, develop a more coherent understanding of abstract concepts of molecular processes during chemical phenomena.     

Assessing high school chemistry students’ modeling sub-skills in a computerized molecular modeling learning environment

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.     

Validation of clay modeling as a learning tool for the periventricular structures of the human brain

Visualizing anatomical structures and functional processes in three dimensions (3D) are important skills for medical students. However, contemplating 3D structures mentally and interpreting biomedical images can be challenging. This study examines the impact of a new pedagogical approach to teaching neuroanatomy, specifically how building a 3D‐model from oil‐based modeling clay affects learners’ understanding of periventricular structures of the brain among undergraduate medical students in Colombia. Students were provided with an instructional video before building the models of the structures, and thereafter took a computer‐based quiz. They then brought their clay models to class where they answered questions about the structures via interactive response cards. Their knowledge of periventricular structures was assessed with a paper‐based quiz. Afterward, a focus group was conducted and a survey was distributed to understand students’ perceptions of the activity, as well as the impact of the intervention on their understanding of anatomical structures in 3D. Quiz scores of students that constructed the models were significantly higher than those taught the material in a more traditional manner (P < 0.05). Moreover, the modeling activity reduced time spent studying the topic and increased understanding of spatial relationships between structures in the brain. The results demonstrated a significant difference between genders in their self‐perception of their ability to contemplate and rotate structures mentally (P < 0.05). The study demonstrated that the construction of 3D clay models in combination with autonomous learning activities was a valuable and efficient learning tool in the anatomy course, and that additional models could be designed to promote deeper learning of other neuroanatomy topics. Anat Sci Educ 11: 137–145. © 2017 American Association of Anatomists.     

Upper Secondary Teachers' Knowledge for Teaching Chemical Bonding Models

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.     

The Interplay Among Children's Negative Family Representations,Visual Processing of Negative Emotions,and Externalizing Symptoms

This study examined the transactional interplay among children's negative family representations, visual processing of negative emotions, and externalizing symptoms in a sample of 243 preschool children (M_age = 4.60 years). Children participated in three annual measurement occasions. Cross‐lagged autoregressive models were conducted with multimethod, multi‐informant data to identify mediational pathways. Consistent with schema‐based top‐down models, negative family representations were associated with attention to negative faces in an eye‐tracking task and their externalizing symptoms. Children's negative representations of family relationships specifically predicted decreases in their attention to negative emotions, which, in turn, was associated with subsequent increases in their externalizing symptoms. Follow‐up analyses indicated that the mediational role of diminished attention to negative emotions was particularly pronounced for angry faces.     

Singapore Students' Perceptions of Graphs,Charts and Maps

Graphs, charts and maps are often used to present quantitative information. Students learn about these in geography, mathematics and other subjects across the curriculum. From contact with school teachers it has been found that many students have problems with graphic representations. This is often seen as a problem of teaching method rather than a problem concerning students' understanding. Studies in Sweden (Ottosson & Aberg-Bengtsson, 1995) and Australia (Gerber et al., 1995) confirm that it is not teaching methods alone that matter. The studies also indicate that the meanings assigned by beholders of graphs, charts and maps are closely linked to their life experiences. This is similarly so for Singapore students. Over thirty students ranging from 11 to 20 years of age were interviewed on their interpretation of a set of graphs, charts and maps of an imaginary world. A phenomenographic analysis shows that the students experienced considerable variations in their perceptions of graphic representations of quantitative data (graphs, charts and maps). These variations are represented in an outcome space diagram showing three major levels of understanding.     

Understanding genetics: Analysis of secondary students' conceptual status

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     

'Lesson Rainbow': the use of multiple representations in an Internet-based, discipline-integrated science lesson

This paper presents the development and evaluation of a web‐based lesson—Lesson Rainbow. This lesson features multiple representations (MRs), which purposefully deliver concepts in relation to distinctive disciplinary subject areas through story‐based animations that are closely related to learners’ life experiences. The researchers selected 58 2nd‐year junior high school students as the participants (32 males and 26 females). A quasi‐experimental method together with semi‐structured interviews was utilised. This research project was intended to investigate students’ conceptual progress, and to evaluate the use of MRs and of situated learning components in the design of Lesson Rainbow. The statistical results indicated that: (1) students’ science concepts significantly increased (t= 3.84, p < 0.01) through the use of Lesson Rainbow, and (2) students thought that the use of MRs in this web‐based lesson was an effective pedagogical tool inasmuch as it allows for the learning of specific theoretical viewpoints in addition to the necessary background information. Lesson Rainbow employing MRs helps learners to understand the meanings of, and interrelationships between, different kinds of external representations. This kind of design facilitates their understanding of the correspondence between abstract symbolic expressions and real‐world situations.     

The Influence of 16‐year‐old Students’ Gender,Mental Abilities,and Motivation on their Reading and Drawing Submicrorepresentations Achievements

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.     

Students' understanding of molecular structure representations

The purpose of the investigation was to determine the meanings attached by students to the different kinds of molecular structure representations used in chemistry teaching. The students (n = 124) were from primary (aged 13-14 years) and secondary (aged 17-18 years) schools and a university (aged 21-25 years). A computerised 'Chemical Visualisation Test' was developed and applied. The research indicates that students' appreciation of three-dimensional molecular structures differs according to the kind of representation used. The best results were achieved with the use of concrete, and pseudo-concrete types of representations (e.g. three-dimensional models, their photographs, computer-generated models). However, the use of more abstract types (e.g. schematic representations, stereochemical formula) was less effective. A correlation between students' results on the Chemical Visualisation Test and their educational level, spatial visualisation, and spatial relations skills was shown statistically, but no statistically significant gender differences were observed.     

The role of submicroscopic and symbolic representations in chemical explanations

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.     

Student Misapplication of a Gas‐like Model to Explain Particle Movement in Heated Solids: Implications for curriculum and instruction towards students’ creation and revision of accurate explanatory models

Understanding the particulate nature of matter (PNM) is vital for participating in many areas of science. We assessed 11 students’ atomic/molecular‐level explanations of real‐world phenomena after their participation in a modelling‐based PNM unit. All 11 students offered a scientifically acceptable model regarding atomic/molecular behaviour in non‐heated solids. Yet, 10 of 11 students expressed the view that, in response to added heat energy, atoms/molecules in a solid increase in movement to a degree beyond what is scientifically accepted. These students attributed a gas‐like model of atomic/molecular movement to situations involving a heated solid. Of the students who held two conflicting models of atomic/molecular movement in solids, almost all provided justification for doing so, indicating their holding of the conflicting models was unproblematic. These findings can be interpreted to mean that students may drop constraints of certain scientific representations and apply, assess, or revise models when explaining unfamiliar phenomena. In fact, we believe students may develop conflicting causal models as a result of misperceptions they acquire, in part, during classroom instruction regarding atomic/molecular movement. However, our findings may also be interpreted as an incidence of student model development that may later aid their understanding of a more complex model, one that involves substantial sub‐atomic electron movement to account for heat transfer in solids. Whether or not this is the case remains to be seen. Implications for student learning and instruction are discussed.     

Learning science through technological design

In the course of a decade of research on learning in technology‐centered classrooms, my research group has gained considerable understanding of why and how students learn science by designing technology. In this article I briefly review two dimensions in which science and technology share fundamental similarities: (a) the production and transformation of representations and (b∥ the action‐oriented language describing the two domains. Because it is fundamentally problematic to derive what ought to happen in science classrooms from other dimensions, I provide three episodes to illustrate what and how students know and learn science during technological design activities. Episodes and analyses embody the two dimensions previously outlined. Because these episodes are representative of the database established during an extensive research program, I suggest there is sufficient ground for using and investigating science‐through‐technology curricula. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 768–790, 2001