The amazingly patient tutor: students' interactions with an online carbohydrate chemistry course

Many multimedia chemistry courses fail to reach their full educational potential as they do not engage the learner in a meaningful task or give appropriate feedback. Though molecular modelling is a recognised technique widely used in chemistry to enable students to grasp difficult concepts, tutorials often do not afford students either the time or scope to learn by experimenting with molecular structures. In this paper we describe the educational development of a web based organic chemistry tutorial which aims to enable students to learn chemical concepts through the manipulation of structural formulae and the provision of appropriate feedback. An online chemical structure modelling tool was developed to enable molecules to be drawn online and to provide feedback. The aim of this study is to address key issues relevant to the development of educational resources of this nature. It will be of particular interest to teachers and lecturers working within Science and Engineering, audio–visual staff and educational developers.     

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.     

School Chemistry: An Historical and Philosophical Approach

Since at least the eighteenth century scientific knowledge (then natural philosophy) was produced in groups of experts and specialists and was transmitted in schools, where, future experts and specialists were trained. The design of teaching has always been a complex process particularly in recent years when educational aims (for example, teaching scientific competence to everyone, not just to experts and specialists) present significant challenges. These challenges are much more than a simple reorganisation of the scientific knowledge pre-determined by the existing teaching tradition for different educational level. In the context of chemical education, the new teaching approaches should bring about not only the transmission of chemical knowledge but also a genuine chemical activity so as to ensure that students can acquire chemical thinking. Chemistry teaching should be revised according to contemporary demands of schooling. In order to move forward towards new teaching proposals, we must identify the genuine questions that generate ‘chemical criteria’ and we should focus on them for teaching. We think that a good strategy is to look for those criteria in the philosophy and history of chemistry, from the perspective of didactics of science. This paper will examine the following questions: (1) How can school science be designed as a world-modelling activity by drawing on the philosophy of science. (2) How can ‘stories’ about the emergence of chemical entities be identified by looking at the history of chemistry? (3) How can modelling strategies be structured in school chemistry activities?     

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.     

Assessing 16-Year-Old Students’ Understanding of Aqueous Solution at Submicroscopic Level

Submicrorepresentations (SMR) could be an important element, not only for explaining the experimental observations to students, but also in the process of evaluating students’ knowledge and identifying their chemical misconceptions. This study investigated the level of students’ understanding of the solution concentration and the process of dissolving ionic and molecular crystals at particulate level, and identifies possible misconceptions about this process. Altogether 408 secondary school students (average age 16.3) participated in the study. The test of chemical knowledge was applied and the analysis of four selected problems related to drawing SMRs in solution chemistry is presented. Selected students were also interviewed in order to gain more detailed data about their way of solving problems comprised in the knowledge test. The average achievement on solution chemistry items was only 43%. It can be concluded from the results that students have different misconceptions about arrangements of solute particles in the solution and presentation of its concentration at particulate level. Students show quite low achievement scores on the problem regarding drawing the SMR of ionic substance aqueous solution (7.6% correct answers) and even lower ones on the problem regarding drawing the SMR of diluted and saturated aqueous solutions of molecular crystal (no completely correct answers). It can be also concluded that many different misconceptions concerning the particulate level of basic solution chemistry concepts can be identified. In the conclusion some implications for teaching to reach a higher level of understanding of solution chemistry are proposed.     

绿色化学理念在化学化工过程中的实施

论述了绿色化学理念和绿色化学的基本原理,重点探讨了绿色化学理念在化学化工过程中的实施,即不断开发新的化学催化过程,提高反应的原子经济性,选用新的合成原料;采用不对称催化剂、分子筛固体酸碱催化剂和生物催化剂等高选择性、高活性的催化剂;采用水、超临界流体、离子液体、氟碳相等无毒无害溶剂和固态反应;重视生物质的利用和化学产品的绿色化等。     

有机化学实验室规范化管理的探索与实践

有机化学实验室的管理是比较繁琐的。从实验室的试剂管理、玻璃仪器管理、实验装置的合理改进和实验室规范化与创新性4个方面入手,进行有机化学实验室规范化管理的探索与实践工作,提高有机化学实验室的管理水平,充分发挥有机化学实验室在实验教学中的作用。把实验室管理工作提高到一个新水平,保证教学质量的不断提高和发展。     

Engaging with Molecular Form to Understand Function

Understanding the relationship between form and function is critical for appreciating biology at the molecular level. This feature explores online materials that connect molecular structures with their functional relevance.Cells are bustling factories with diverse and prolific arrays of molecular machinery. Remarkably, this machinery self-organizes to carry out the complex biochemical activities characteristic of life. When Watson and Crick published the structure of DNA, they noted that DNA base pairing creates a double-stranded form that provides a means of accurately copying the genetic information. Understanding this link between form and function is important for understanding the basis of any biological activity. At the most basic level, a biomolecule''s function is dictated by its structure. The molecule''s shape and chemical properties facilitate interactions with other molecules and determine its role in the cell. Protein function depends on the precise folding of encoded linear stretches of amino acids into three-dimensional shapes. Protein misfolding can lead to various disease states. In this review, we explore engaging online resources that highlight the connection between structure and function in biomolecules. These resources are particularly relevant for instruction at the advanced high school and undergraduate biology levels.     

Using virtual laboratories in chemistry classrooms as interactive tools towards modifying alternate conceptions in molecular symmetry

Molecular symmetry plays a central role in chemistry education with regard to predicting chemical properties such as bonding and spectroscopic transitions. Better understanding of the symmetry of molecules requires high visual-spatial thinking ability. Conventional teaching methodologies, with limited teaching aides, fall short in providing a detailed understanding of scientific theories and related concepts. Incorrect understanding has been known to perpetrate concepts that are not consistent with the consensus of the research community or alternate conceptions. This work elaborates a methodology designed to discover the alternate conceptions stemming from teaching molecular symmetry in a typical classroom environment and the impact of the virtual laboratory (VL) environment in correcting these misconceptions. Three significant contributions presented in this paper include: (1) the development of a media and information-intense VL experiment platform designed to enhance understanding of symmetry elements and point groups of molecules with diverse structural geometries. (2) the development of an instrument, Molecular symmetry Alternate Conception Test (MACT), designed to capture and estimate the extent of alternate conceptions. (3) the successful identification of typical alternate conceptions amongst students in the context of molecular symmetry. In addition to perceived alternate concepts in symmetry education, the results indicate a significant statistical improvement of 156% in understanding of molecular symmetry concepts (p?<?0.05) after subjecting students to the interactive VL platform. This study also shows identifying bond angles and planarity as concepts crucial for students. It is also implicit that estimations of discrimination skills related to identifying concept-based learning may be relevant for perceiving alternate concepts among learners.     

Eliciting Metacognitive Experiences and Reflection in a Year 11 Chemistry Classroom: An Activity Theory Perspective

Concerns regarding students’ learning and reasoning in chemistry classrooms are well documented. Students’ reasoning in chemistry should be characterized by conscious consideration of chemical phenomenon from laboratory work at macroscopic, molecular/sub-micro and symbolic levels. Further, students should develop metacognition in relation to such ways of reasoning about chemistry phenomena. Classroom change eliciting metacognitive experiences and metacognitive reflection is necessary to shift entrenched views of teaching and learning in students. In this study, Activity Theory is used as the framework for interpreting changes to the rules/customs and tools of the activity systems of two different classes of students taught by the same teacher, Frances, who was teaching chemical equilibrium to those classes in consecutive years. An interpretive methodology involving multiple data sources was employed. Frances explicitly changed her pedagogy in the second year to direct students attention to increasingly consider chemical phenomena at the molecular/sub-micro level. Additionally, she asked students not to use the textbook until toward the end of the equilibrium unit and sought to engage them in using their prior knowledge of chemistry to understand their observations from experiments. Frances’ changed pedagogy elicited metacognitive experiences and reflection in students and challenged them to reconsider their metacognitive beliefs about learning chemistry and how it might be achieved. While teacher change is essential for science education reform, students are not passive players in change efforts and they need to be convinced of the viability of teacher pedagogical change in the context of their goals, intentions, and beliefs.     

Generative mechanistic explanation building in undergraduate molecular and cellular biology*

ABSTRACT

When conducting scientific research, experts in molecular and cellular biology (MCB) use specific reasoning strategies to construct mechanistic explanations for the underlying causal features of molecular phenomena. We explored how undergraduate students applied this scientific practice in MCB. Drawing from studies of explanation building among scientists, we created and applied a theoretical framework to explore the strategies students use to construct explanations for ‘novel’ biological phenomena. Specifically, we explored how students navigated the multi-level nature of complex biological systems using generative mechanistic reasoning. Interviews were conducted with introductory and upper-division biology students at a large public university in the United States. Results of qualitative coding revealed key features of students’ explanation building. Students used modular thinking to consider the functional subdivisions of the system, which they ‘filled in’ to varying degrees with mechanistic elements. They also hypothesised the involvement of mechanistic entities and instantiated abstract schema to adapt their explanations to unfamiliar biological contexts. Finally, we explored the flexible thinking that students used to hypothesise the impact of mutations on multi-leveled biological systems. Results revealed a number of ways that students drew mechanistic connections between molecules, functional modules (sets of molecules with an emergent function), cells, tissues, organisms and populations.     

高考试题中的化学核心素养探析——以2018—2019年全国卷Ⅱ化学试题为例

以2018年和2019年高考全国卷Ⅱ化学试题为例,统计在高考试题中化学核心素养的考查比重.结果表明,EM素养占比最高,分值最大,MM和SI素养的占比相接近,而SS考查比重最小;不同水平上也存在差异性,MM和EM素养在初级水平考查的比重较大,而SI和CE素养重点考查水平3和水平4.基于此,提出相应的化学教学启示.     

研究型分子生物学实验课程体系建立与实践

分子生物学是在分子水平上研究生物生长发育的调控机制及其遗传基础,其基本理论的建立依赖于实验,因此也是实验性非常强的学科。分子生物学实验课程是培养高素质生物类本科人才必修课程。目前我国大学本科分子生物学实验课程多数滞后于该学科发展,制约了人才培养。学校构建新实验课程教学体系,直接将相关的科研成果转化为本科实验教学项目,制定了一套系统性强,能够培养本科生综合能力的研究型分子生物学实验课程体系。通过近2年的教学实践,取得了良好的教学效果。     

A Transformative Model for Undergraduate Quantitative Biology Education

The BIO2010 report recommended that students in the life sciences receive a more rigorous education in mathematics and physical sciences. The University of Delaware approached this problem by (1) developing a bio-calculus section of a standard calculus course, (2) embedding quantitative activities into existing biology courses, and (3) creating a new interdisciplinary major, quantitative biology, designed for students interested in solving complex biological problems using advanced mathematical approaches. To develop the bio-calculus sections, the Department of Mathematical Sciences revised its three-semester calculus sequence to include differential equations in the first semester and, rather than using examples traditionally drawn from application domains that are most relevant to engineers, drew models and examples heavily from the life sciences. The curriculum of the B.S. degree in Quantitative Biology was designed to provide students with a solid foundation in biology, chemistry, and mathematics, with an emphasis on preparation for research careers in life sciences. Students in the program take core courses from biology, chemistry, and physics, though mathematics, as the cornerstone of all quantitative sciences, is given particular prominence. Seminars and a capstone course stress how the interplay of mathematics and biology can be used to explain complex biological systems. To initiate these academic changes required the identification of barriers and the implementation of solutions.     

Cognitive development and problem solving of Afro-American students in chemistry

The aims of this study were to investigate the level of cognitive development of Afro-American students enrolled in general chemistry courses at the college level and to determine the strategies used by both successful and unsuccessful Afro-American students in solving specific types of stoichiometric problems. It was found that the choice of a strategy is not significantly related to cognitive development of the student in specific types of stoichiometric problems. However, the following trend was noted: Students who are formal-operational in thought are more likely to be successful when solving mole-volume problems and complex mole-mole problems than are their concrete-operational counterparts. Additionally, a systematic strategy proved to be successful for the students, regardless of the cognitive development, when balancing simple and complex chemical equations. Also, algorithmic/reasoning strategies were needed to solve the mole-volume problem. A higher level of cognitive development and reasoning may be crucial factors in solving the more sophisticated types of problems in stoichiometry.     

A cross-age study of the understanding of five chemistry concepts

A sample of 100 students from junior high school physical science, high school chemistry, and introductory college chemistry were examined for understanding of five chemistry concepts. The concepts addressed were chemical change, dissolution of a solid in water, conservation of atoms, periodicity, and phase change. The amount of experience with the concepts (grade level) and reasoning ability (developmental level) were examined as possible sources of variation in student understanding. Differences in understanding with respect to grade level were found to be significant for the concepts of chemical change, dissolution of a solid, conservation of atoms, and periodicity. However, few of the students in the college chemistry sample exhibited sound understanding of chemical change, periodicity, or phase change. The use of particulate terms (atoms, ions, molecules) increased across the grade levels. Reasoning ability proved to be a significant factor for student understanding of conservation of atoms and periodicity. An examination of the number and types of misconceptions across the grade levels revealed several interesting patterns and suggested sources for the students' alternative conceptions.     

Towards Eco-reflexive Science Education

The modern world can be described as a globalized risk society. It is characterized by increasing complexity, unpredictable consequences of techno-scientific innovations and production, and its environmental consequences. Therefore, chemistry, just like many other knowledge areas, is in an ongoing process of environmentalization. For example, green chemistry has emerged as a new chemical metadiscipline and movement. The philosophy of green chemistry was originally based on a suggestion of twelve principles for environment-friendly chemistry research and production. The present article problematizes limitations in green chemistry when it comes to education. It argues that the philosophy of green chemistry in the context of education needs to be extended with socio-critical perspectives to form educated professionals and citizens who are able to understand the complexity of the world, to make value-based decisions, and to become able to engage more thoroughly in democratic decision-making on sustainability issues. Different versions of sustainability-oriented science/chemistry education are discussed to sharpen a focus on the most complex type, which is Bildung-oriented, focusing emancipation and leading to eco-reflexive education. The term eco-reflexive is used for a problematizing stance towards the modern risk society, an understanding of the complexity of life and society and their interactions, and a responsibility for individual and collective actions towards socio-ecojustice and global sustainability. The philosophical foundation and characteristics of eco-reflexive science education are sketched on in the article.     

Aneesur Rahman

Aneesur Rahman made seminal contributions to computational physics, the forerunner of the widespread application today of computation in the study of physical, chemical and biological phenomena. This year marks the 50th anniversary of his paper in 1964, which heralded the use of the molecular dynamics method, an essential tool for research in materials and biological sciences today, which he is most known for. A biography of Rahman, along with a summary of his scientific contributions is described below.     

Molecular modeling: A powerful tool for drug design and molecular docking

Molecular modeling has become a valuable and essential tool to medicinal chemists in the drug design process. Molecular modeling describes the generation, manipulation or representation of three-dimensional structures of molecules and associated physico-chemical properties. It involves a range of computerized techniques based on theoretical chemistry methods and experimental data to predict molecular and biological properties. Depending on the context and the rigor, the subject is often referred to as ‘molecular graphics’, ‘molecular visualizations’, ‘computational chemistry’, or ‘computational quantum chemistry’. The molecular modeling techniques are derived from the concepts of molecular orbitals of Hückel, Mullikan and ‘classical mechanical programs’ of Westheimer, Wiberg and Boyd.     

Chemistry at the Nanoscale

Traditionally the kinetics of a chemical reaction has been studied as a set of coupled ordinary differential equations. The law of mass action, a tried and tested principle for reactions involving macroscopic quantities of reactants, gives rise to deterministic equations in which the variables are species concentrations. In recent years, though, as smaller and smaller systems – such as an individual biological cell, say – can be studied quantitatively, the importance of molecular discreteness in chemical reactions has increasingly been realized. This is particularly true when the system is far from the ‘thermodynamic limit’ when the numbers of all reacting molecular species involved are several orders of magnitude smaller than Avogadro’s number. In such situations, each reaction has to be treated as a probabilistic ‘event’ that occurs by chance when the appropriate reactants collide. Explicitly accounting for such processes has led to the development of sophisticated statistical methods for simulation of chemical reactions, particularly those occurring at the cellular and sub-cellular level. In this article, we describe this approach, the so-called stochastic simulation algorithm, and discuss applications to study the dynamics of model regulatory networks.