Effects of Combined Hands-on Laboratory and Computer Modeling on Student Learning of Gas Laws: A Quasi-Experimental Study

Based on current theories of chemistry learning, this study intends to test a hypothesis that computer modeling enhanced hands-on chemistry laboratories are more effective than hands-on laboratories or computer modeling laboratories alone in facilitating high school students' understanding of chemistry concepts. Thirty-three high school chemistry students from a private all-girl high school in northeastern United States were divided into two groups to participate in a quasi-experimental study. Each group completed a particular sequence of computer modeling and hands-on laboratories plus pre-test and post-tests of conceptual understanding of gas laws. Each group also completed a survey of conceptions of scientific models. Non-parametric tests, i.e. Friedman's one-way analysis of ranks and Wilcoxon's signed ranks test, showed that the combined computer modeling and hands-on laboratories were more effective than either computer simulations or hands-on laboratory alone in promoting students' conceptual understanding of the gas law on the relationship between temperature and pressure. It was also found that student conception of scientific models as replicas is statistically significantly correlated with students' conceptual understanding of the particulate model of gases. The findings mentioned earlier support the recent call for model-based science teaching and learning in chemistry.     

College chemistry students' mental models of acids and acid strength

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     

Year 12 Students' Mental Models of the Nature of Light

This article reports on the third year of a three-year longitudinal investigation into six secondary students' understanding of optics at a secondary school level. In the third year of this investigation the students, who by now were in Year 12, underwent a teaching sequence that centred on the teaching and learning of physical optics and quantum ideas. The students' mental models of the nature of light were explored prior to, and following this teaching sequence. The researcher took on the dual roles of teacher and researcher. This paper will outline the findings of the third year of this study and the implications they have for the teaching and learning of optics at secondary school level.     

The Mismatch between Students’ Mental Models of Acids/Bases and their Sources and their Teacher’s Anticipations thereof

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.     

The Use of Video Demonstrations and Particulate Animation in General Chemistry

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.     

The nature of scientific knowledge and student learning: Two longitudinal case studies

This study was designed to investigate the relationship between students' views of the nature of scientific knowledge and their own learning of physics, and the evolution of this relationship over time. Twenty-three students enrolled in a physics course that emphasised laboratory work and discussions about the nature of science. Over a 15-month period, an extensive data base was established including student essays and interviews regarding their views of the nature of science and teaching and learning of physics. As part of an extensive data generation, students read a book on the epistemology of physics, wrote reflective essays, and subsequently discussed the epistemology of physics in class. Two intensive case studies are used to illustrate our understanding of students' views over time. Changes in students' views concerning the nature of scientific knowledge and of the science teaching and learning process, which were not always complementary, are described with the aid of a model. The findings of this research have direct relevance to the planning and implementation of science courses in which the development of understandings of the nature of science is an objective.     

理科教师的科学本质观对科学教育的影响

人们对科学本质的认识经历了由科学的“真理观”向科学的“建构观”的转变。不同的科学本质观将直接影响着教师对科学教育目标的不同理解,对科学知识的不同选择,对教学主题的不同设计、教学话语的不同使用,对学生学习的不同评价。教师不同的科学本质观及其教学行为影响着学生的科学本质观的形成,影响着学生对科学内容的理解以及看待问题的思维方式。     

在中学化学教学中情感教育的实施

在新课程改革教学中,越来越重视学生综合素质的发展和培养,以往的教学中教育者往往过分重视学生的认知教育,而忽视学生的情感教育,导致学生的学业和未来人生不能和谐地发展。作为一名化学教师,要不断地思考怎样的教学是最有效的教学,如何把学生的智力因素和非智力因素统一结合起来,引导学生积极主动地学习,形成积极的情感态度和正确的价值观,提高科学素养。在化学教学中渗透情感教学有利于培养学生学习化学的兴趣,能唤起学生学习的积极情感,使学生变消极学习为积极学习,提高学生对化学学科的兴趣,调动学生学习的积极性,增加学生的学习动力,有效地提高化学教学的效果。     

High-School Chemistry Students' Performance and Gender Differences in a Computerized Molecular Modeling Learning Environment

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.     

Mapping undergraduate chemistry students' epistemic ideas about models and modeling

Developing and using scientific models is an important scientific practice for science students. Undergraduate chemistry curricula are often centered on established disciplinary models, and assessments typically provide students with opportunities to use these models to predict and explain chemical phenomena. However, traditional curricula generally provide few opportunities for students to consider the epistemic nature of models and the process of modeling. To gain a sense of how introductory chemistry students understand model changeability, model multiplicity, the evaluation of models, and the process of modeling, we use a construct-mapping approach to characterize the sophistication of students' epistemic knowledge of models and modeling. We present a set of four related construct maps that we developed based on the work of other scholars and empirically validated in an undergraduate introductory chemistry setting. We use the construct maps to identify themes in students' responses to an open-ended survey instrument, the models in chemistry survey, and discuss the implications for teaching.     

高等学校心理健康教育课程的调查与分析——提高大学生心理健康意识是心理健康教育的关键

为了了解大学生对于心理健康教育课程的课程目标、课程内容、授课形式的认识,以及他们对授课教师能力与素质的要求,促进高校心理健康教育课程的科学化建设,采用分层随机取样的方法对367名大学一年级至四年级学生进行了调查。分析结果表明:提高大学生心理健康意识是高校心理健康教育的关键;心理健康教育需要面向全体学生,不同年级的大学生对心理健康教育有不同的需求;体验活动和案例教学是大学生最喜欢的授课形式;大学生认为,丰富的心理咨询经验是心理健康教育教师最需要具备的能力与素养。     

科学的本质与学生科学本质观的培养

开展科学的本质教育是培养学生科学素养的核心内容。正确的科学本质观建立在科学知识、科学方法以及科学情感态度与价值观的形成基础之上。通过实施新的科学教育理念,改革科学课程的教学内容,转变教师教学策略,使学习科学成为学生主动探究的过程,必将进一步引导学生加深对科学本质的认识和理解,促进学生科学本质观的形成与发展。     

图示法在化学教学中的作用

图示法是一种新的化学教育研究方法.该文提出利用图示法在化学教学中可以提高学生的学习兴趣、培养学生的各种能力、发展思维能力;有利于突出教材的重点及难点;可以优化知识结构,形成知识体系,增强学生对知识的理解和记忆,还可以使计算简化;有助于教师获得反馈信息,检查教学效果.     

Students’ Mental Models of the Internet and Their Didactical Exploitation in Informatics Education

The Internet constitutes a relatively new teaching subject for the Informatics curriculum. Within secondary education, students should develop an understanding of basic Internet concepts as well as Internet skills. For the attainment of these goals it is necessary that they develop adequate mental models of the Internet. That development should be based on the assessment of their initial mental models of the Internet. The purpose of this study was the investigation of the mental models that high school students form of the Internet in the beginning of the Informatics curriculum. The study involved 340 Greek high school students who completed a written questionnaire and a drawing task. The results suggest that students form simplistic, utilitarian rather than structural mental models of the Internet, which would provide them with an adequate explanatory system of what the Internet actually is and the processes underlying its use. The students’ mental models also involve particular misconceptions. The didactical implications of the findings for Informatics education at high school level are considered.     

Students' Visualization of Metallic Bonding and the Malleability of Metals

This study investigated the mental representations of metallic bonding and the malleability of metals held by three male students aged 14–15 (Year 10) who were attending a Hong Kong school. One student was selected by their chemistry teacher as representing each of the highest, the medium, and the lowest level of attainment in chemistry in a school that admitted students of average general attainment. The students were interviewed and their understandings probed through their provision of drawings and their interpretation of the diagrams that had been previously used by their teacher. Dual coding theory was used to interpret the relative significance of visual and verbal input and the interaction between the two for their understanding. There was evidence that students relied on verbal recall in providing their initial understandings and showed an appreciation of the nature of the structural components of the electron-sea model of metallic bonding. However, they varied in terms of their appreciation of the electrostatic force which was responsible for the malleability of metals. The study suggests that a clearer understanding of the electrostatic force involved can be attained when students experience visual and verbal representations simultaneously, a conclusion supported by dual coding theory. Principles for good practice in using diagrams in teaching are discussed.     

Understandings and misunderstandings of eighth graders of five chemistry concepts found in textbooks

The research reported in this study was designed to answer three questions: (a) What misconceptions do eighth grade students have concerning the chemistry concepts from their textbooks. (b) How is reasoning ability related to misconceptions concerning chemistry concepts. (c) How effective are textbooks in teaching an understanding of chemistry concepts? Five chemistry concepts were used in the study: chemical change, dissolution, conservation of atoms, periodicity, and phase change. Problems concerning the five concepts were given to 247 eighth-grade students in order to assess the students' degree of understanding of chemistry concepts and to identify specific misconceptions. Two pencil-and-paper Piaget-type tasks were used to assess intellectual level. A comparison of intellectual level and scores on the chemistry concepts showed moderate correlations. However, the small number of formal operational students in the sample makes these results inconclusive. A study of the level of understanding of the five chemistry concepts and the nature of the misconceptions held by students indicate a general failure of textbooks to teach a reasonable understanding of chemistry concepts.     

The Nature of Science and Scientific Knowledge: Implications for a Preservice Elementary Methods Course

This article describes teaching considerations related to the nature of science and scientific knowledge in an elementary science methods course. The decisions that were made, the rationale upon which these decisions were based, and the challenges evident are presented. Instructional strategies used during the course for the purpose of developing preservice teachers' understandings of the nature of science and scientific knowledge are described. The results of using these strategies, in regard to the impact on students' learning and their views on teaching the nature of science to elementary grade students are then discussed. The article concludes with a discussion on the implications for teaching the nature of science and scientific knowledge in the context of preservice elementary teacher education.     

Undergraduate Understanding of Climate Change: The Influences of College Major and Environmental Group Membership on Survey Knowledge Scores

A survey covering the scientific and social aspects of climate change was administered to examine U.S. undergraduate student mental models, and compare knowledge between groups based on major and environmental group membership. A Knowledge Score (scale 0–35, mean score = 17.84) was generated for respondents at two, central East Coast, U.S. universities (n = 465). Elements of student mental models examined include environmental issue confusion, skepticism, and self-reported understanding. This study finds that students frequently confuse climate change with other environmental issues, and that a substantial majority of students do not have an understanding of climate change that closely matches the scientific model. These misconceptions extend to their understanding of mitigation actions. Environmental group membership is shown to be a greater determinant of climate change knowledge than enrollment in a science major.     

Promoting preservice chemistry teachers' understanding about the nature of science through history

The purpose of this quasi‐experimental study was to document the benefits of teaching chemistry through history. The experimental group consisted of seniors enrolled in a teacher preparation program in which they learned how to teach chemistry through the history of science. Their understanding of the nature of science was compared with that of a control group, which consisted of juniors in the same department. The results of the analysis of covariance revealed that the experimental group outperformed the control group on an instrument documenting respondents' understanding of the nature of science. Additional frequency analysis and interview data indicated that the experimental group students had a better understanding of the nature of creativity, the theory‐based nature of scientific observations, and the functions of theories. In the pretreatment interviews, students in the experimental group based their explanations concerning the nature of science primarily on their intuition. In the posttreatment interview, however, they were able to explain their beliefs by using scientists' arguments or hypotheses as examples. This result indicates that the experimental group's understanding about the nature of science was enhanced by learning to teach through the history of science. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 773–792, 2002