Understanding Of Chemical Concepts Research Articles

Preparedness for tertiary chemistry: issues of placement and performance

The introduction of an outcomes-based curriculum in South Africa together with a new syllabus for physical sciences for grades 10–12, prompted the development of an instrument to monitor conceptual understanding in chemistry at the secondary-tertiary interface. This instrument was used to evaluate placement within different programmes at tertiary institutions as well as improvement in the conceptual understanding of chemistry during the first year of instruction. Comparison of preparedness revealed distinct profiles for proficiencies of mainstream and academic development cohorts, respectively, at the Universities of Cape Town, UCT, and Pretoria, UP, but not at the University of Limpopo, UL, which raises doubts about the placement of students at that institution. Unnecessary duplication of offerings for under-prepared students was found at UP. The academic development programmes at UCT and UP were effective in raising the level of conceptual understanding of students while students in the UL programme showed very little improvement. South African Journal of Higher Education Vol. 22 (4) 2008: pp. 861-876

The effect of an individualized laboratory approach through microscale chemistry experimentation on students' understanding of chemistry concepts, motivation and attitudes

The main goal of this study was to investigate whether the use of an individualized approach through microscale chemistry experiments in secondary schools can increase students’ understanding of chemistry concepts, improve attitude towards chemistry practical work and motivation. Two comparable groups of Form Four students (16 years old) participated. The students in the experimental group (83) worked individually on ten microscale chemistry experiments, whereas the control group (87) worked in groups on traditional experiments both for a period of 8 weeks. Pre and post tests were conducted before and after the treatment for both groups. Teacher and student perceptions of microscale experimentation are also reported. Findings showed that the microscale approach can increase understanding of chemistry concepts, however, there was no significant difference in attitude and motivation among the students. Teachers and students both had a positive view of microscale experiments.

Mapping student understanding in chemistry: The Perspectives of Chemists

AbstractPreliminary pilot studies and a field study show how a generalizable conceptual framework calibrated with item response modeling can be used to describe the development of student conceptual understanding in chemistry. ChemQuery is an assessment system that uses a framework of the key ideas in the discipline, called the Perspectives of Chemists, and criterion‐referenced analysis using item response models (item response theory (IRT)) to map student progress. It includes assessment questions, a scoring rubric, item exemplars, and a framework to describe the paths of student understanding that emerge. Integral to criterion‐referenced measurement is a focus on what is being measured: the intention of the assessment, its purpose, and the context in which it is going to be used. The Perspectives framework allows us to begin to narrate the development of understanding that occurs as students “learn'' over the course of instruction, helping to form a crosswalk among educational science standards and underscore the importance of scientific reasoning with domain knowledge. Here, we explain a framework we have investigated in chemistry and present evidence on measures of student understanding to describe the development of conceptual understanding at the high school and university levels. © 2008 Wiley Periodicals, Inc. Sci Ed 93:56–85, 2009

Assessment of preparedness of first-year chemistry students: development and application of an instrument for diagnostic and placement purposes

Many universities in South Africa use alternative admissions tests together with results of the Grade 12 examinations for access or placement. These tests focus on academic literacy and mathematical skills and do not provide information about proficiencies in disciplines other than mathematics. The implementation of a new curriculum for Grades 10–12 in South Africa generates a need to monitor preparedness of first-year students to align first-year curricula as closely as possible to the content of the new syllabi. The need for a tailor-made instrument to assess preparedness for chemistry at the tertiary level was prompted by the lack of suitable tests with the appropriate focus, depth and coverage for application in the South African context. This paper describes the development and evaluation of a test instrument designed to assess and monitor baseline conceptual understanding in chemistry at the secondary-tertiary interface. The study was carried out with mainstream students at the universities of Pretoria and Cape Town (N = 513 and 258, respectively). Data analysed using the Rasch statistical method confirmed that the majority of students from both cohorts was reasonably well prepared for chemistry at the tertiary level. The use of the instrument for diagnostic purposes was demonstrated. It was possible to identify gaps in the assumed pre-knowledge of students who have qualified for admission to chemistry at a tertiary level at their respective institutions. Inadequate pre-knowledge was most noticeable in the areas of chemical reactions and electrochemistry. In addition, the instrument also shows promise as a placement tool within programmes at a particular institution, i.e. in either mainstream or academic development programmes. Its predictive ability compares well with non-South African placement tests and with Grade 12 mathematics performance, the latter is widely used for this purpose in South Africa.

Síntese de biodiesel: uma proposta contextualizada de experimento para laboratório de química geral

The contextualized understanding of concepts in Chemistry by students from other areas is a challenging task. In this experiment, the synthesis of biodiesel is done by base catalyzed transesterification of refined soy oil with methanol at room temperature and common glassware found in any chemistry laboratory. The proposal permits introducing several concepts, such as that of emulsion, viscosity and catalysis to illustrate an activity based on an actual problem. In this didactic approach, some common problems of biodiesel production, such as soap formation and phase separation, are introduced into the procedure in order to raise questions and motivate the students to participate in the experimental work and stimulate reflections about critical aspects of biodiesel production. This experiment was carried out in the first semester of 2006, in experimental general chemistry taken by physics and agricultural, civil and chemical engineering students of UNICAMP.

Two Kinds of Conceptual Problems in Chemistry Teaching

The use of conceptual questions is one tool that can assist students in obtaining a deeper learning experience, improve their understanding and ability to apply learning to new situations, enhance their critical thinking, and increase their enthusiasm for science and learning. The performance of first-year science students with two forms of conceptual questions was investigated. The results indicate that students might have problems solving conceptual questions without reference to the question form (verbal or pictorial). The depth of students' understanding of chemical concepts seems to play an important role.

Student affect and conceptual understanding in learning chemistry

AbstractThis study explores the relationship between affective and cognitive variables in grade 9 chemistry students (n = 73). In particular, it explores how students' situational interest, their attitudes toward chemistry, and their chemistry‐specific self‐concept influence their understanding of chemistry concepts over the course of a school year. All affective variables were assessed at two time points: at the middle of the first semester of grade 9, and at the end of the second semester of grade 9, and then related to students' postinstructional understanding of chemical concepts. Results reveal that none of the affective variables measured at the earliest time point have a significant direct effect on postinstructional conceptual understanding. Looking at the different affective variables as intermediary constructs, however, reveals a pattern in which self‐concept and situational interest measured at the middle of grade 9 contribute to self‐concept measured at the end of grade 9, which in turn, has a positive, significant effect on students' postinstructional conceptual understanding. These results reveal the importance of a strong and positive self‐concept, the feeling of doing well in the chemistry class, for developing a meaningful understanding of scientific concepts. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 908–937, 2007

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.

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A Comparison Study: Assessing Teachers' Conceptions with the Chemistry Concepts Inventory

"Science as inquiry" is a key component of the National Science Education Standards. A deep conceptual understanding of chemistry is critical to the successful implementation of inquiry-based lessons. In this paper we report the results of a study to assess alternate conceptions of teachers in a large urban district—many of whom are teaching out-of-discipline—to further inform professional development activities related to the adoption of a reform-based chemistry curriculum. Teacher responses to the Chemistry Concepts Inventory were analyzed to assess alternate conceptions, and correlations were made to previously reported alternate conceptions of entering college students. The teachers scored higher than students on all items, however, the teachers' answers generally demonstrated a distribution similar to students of most commonly incorrect items and alternate conceptions, most of which involved translating between macroscopic, microscopic, and symbolic representations. Potential origins and impacts of the teachers' alternate conceptions on teaching and student learning are discussed. This study reinforces the need for content-focused training toward the development of out-of-discipline chemistry teachers' conceptual understanding of chemistry, and specifically in making meaningful connections between observations of macroscopic phenomena and explanations at the particulate level.

Connected Chemistry - A Novel Modeling Environment for the Chemistry Classroom

This article introduces a novel learning environment for teaching chemistry, Connected Chemistry, and describes its potential use in a high school and undergraduate chemistry classrooms. Connected Chemistry comprises several molecular simulations and is designed to enable instructors to teach chemistry using the perspective of "emergent phenomena". That is, it allows students to see observed macro-level chemical phenomena, like many other scientific phenomena, as resultant from the interactions of many individual agents on a micro-level. This perspective is especially appropriate to the study of chemistry where the interactions between multitudes of molecules on the atomic level give rise to the macro-level concepts that students study in the classroom. For example, physical processes such as melting and evaporation and the concepts of pressure and temperature result from such molecular interactions, which students cannot observe directly. Modeling environments such as Connected Chemistry provide students with the opportunity to observe these interactions in a simulated chemical reaction to aid students in developing a deeper understanding of chemistry concepts and processes in the classroom and laboratory. Here, the pedagogical foundations of Connected Chemistry are presented as well as three potential applications of the software: as a classroom visualization tool, a laboratory simulator, and a student feedback tool.

Chemical concepts inventory of Grade 12 learners and UP foundation year students

Incoming chemistry students at tertiary institutions have a variety of academic backgrounds that influence their prospects of success at first-year level. The proficiencies of incoming students are currently changing due to the introduction of outcomes-based education and new syllabi for physical science in secondary schools. In order to ensure a smooth transition from secondary to tertiary education, university lecturers should be well informed about the content knowledge, conceptual understanding and skills development of prospective first-year students. This study evaluates the proficiencies of Grade 12 learners in physical science in terms of a number of clearly identified problem areas: conceptual understanding, logical scientific reasoning, basic mathematical ability, knowledge of subject content and scientific process skills. A test instrument was developed that consisted mainly of conceptual questions rather than recall or algorithmic items. Paired questions (two-tier methodology) and pictorial representations were used extensively. A follow-up question about certainty of response was included for all fixed-response items in order to evaluate the influence of guessing on response distributions. The test instrument was administered at the end of the third term to Grade 12 learners taking Physical science at three schools in privileged environments (1 English and 2 Afrikaans medium) and four township schools, and to all University of Pretoria Foundation Year (UPFY) students.Analysis of results highlighted the generally poor performance of students from township schools and the significant improvement in performance after one year of intensive instruction of UPFY students, who generally came from similar or more impoverished backgrounds. The poor performance for all cohorts on basic concepts, such as the mole concept, stoichiometry and the limiting reagent, as well as on several special topics, indicates that students lack a sound basis for tertiary chemistry. Of real concern is the evidence of over-confidence obtained from the certainty of response analyses. This result indicates that respondents failed to judge the complexity and level of difficulty of questions accurately. Learners/students from all groups displayed weak understanding of events at molecular level. In order to address this situation, lecturers at tertiary level will have to actively promote conceptual understanding of all basic concepts in chemistry and resist the temptation to teach and assess mainly procedural fluency. Analysis of certainty of response data showed that the guess factor was less serious a complication than anticipated.

Connected Chemistry—Incorporating Interactive Simulations into the Chemistry Classroom

The aim of this paper is to describe a novel modeling and simulation package, connected chemistry, and assess its impact on students’ understanding of chemistry. Connected chemistry was implemented inside the NetLogo modeling environment. Its design goal is to present a variety of chemistry concepts from the perspective of “emergent phenomena”—that is, how macro-level patterns in chemistry result from the interactions of many molecules on a submicro-level. The connected chemistry modeling environment provides students with the opportunity to observe and explore these interactions in a simulated environment that enables them to develop a deeper understanding of chemistry concepts and processes in both the classroom and laboratory. Here, we present the conceptual foundations of instruction using connected chemistry and the results of a small study that explored its potential benefits. A three-part, 90-min interview was administered to six undergraduate science majors regarding the concept of chemical equilibrium. Several commonly reported misconceptions about chemical equilibrium arose during the interview. Prior to their interaction with connected chemistry, students relied on memorized facts to explain chemical equilibrium and rigid procedures to solve chemical equilibrium problems. Using connected chemistry students employed problemsolving techniques characterized by stronger attempts at conceptual understanding and logical reasoning.

A Conceptual Change Teaching Strategy to Facilitate High School Students' Understanding of Electrochemistry

Recent research in chemistry education has shown an increasing interest in the facilitation of conceptual change in student understanding of chemical concepts. Most of the studies have tried to show the difference in student performance on algorithmic and conceptual problems. The objective of this study is to go beyond and design a teaching strategy based on two “teaching experiments” that could facilitate students' conceptual understanding of electrochemistry. The study is based on two sections (control, n = 29; experimental, n = 28) of 10th grade high school students at a public school in Venezuela. Experimental group participated in two teaching experiments designed to generate situations/experiences in which students are forced to grapple with alternative responses leading to cognitive conflicts/contradictions. Results obtained show that learning electrochemistry involves both algorithmic and conceptual problems. On Posttest 1, 93% of the experimental group students responded correctly, in contrast to 39% of the control group. On Posttest 2, 39% of the experimental group responded correctly, in contrast to 0% of the Control group. The difference in performance on both posttests is statistically significant (p < 0.001). It is concluded that the “teaching experiments” facilitated students' understanding (progressive transitions) of electrochemistry.

Collaborating to enhance student reasoning: Frances' account of her reflections while teaching chemical equilibrium

Many researchers report that teachers' pedagogies often reflect non-constructivist referents, however less research reports on means of assisting teachers to become more constructivistly oriented. This paper reports on a teacher's changing perceptions during collaborative, two-year interpretive research involving two researchers, herself, and her students. The researchers collaborated with the teacher to promote students' theory-evidence coordination and use of word explanations, with an emphasis on developing and critiquing chemical equilibrium theory using experimental data. As the collaboration proceeded the teacher's beliefs and practice became increasingly focussed on students' reasoning and their discussion of ideas related to experimental data. The teacher reported benefits for herself and for her students as a consequence of this change. Key factors in relation to this change included researchers' modelling of target practices, and changes in the teacher's (a) perception of her students' abilities, (b) beliefs in relation to constructivism, and (c) understanding of chemistry concepts.

Using Computer-Based Visualization Strategies to Improve Students' Understanding of Molecular Polarity and Miscibility

This study reports how instruction including visualization strategies associated with computer animations and electron density plots affected students' conceptual understanding of two chemistry topics. Two sets of students responded to several conceptual questions about molecular polarities and miscibilities and these responses were compared. One group received instruction including the use of wooden model kits and physical demonstrations; the other received similar instruction with the additional use of computer animations and electron-density plots. Students who viewed electron-density plots were more likely to identify symmetric molecules with polar bonds as being nonpolar and provided more complete descriptions of how soap molecules help remove grease from an object. Students who viewed computer animations and electron density plots were also more likely to explain that the intermolecular attractions among water molecules are responsible for the immiscibility of oil and water, and were more likely to recognize that water molecules are attracted to each other and to sodium and chloride ions but are not strongly attracted to hydrogen molecules. Although other studies have shown that computer animations can improve students' conceptual understanding of chemistry, this is the first to demonstrate that electron-density plots mapped with electrostatic potentials can also be an effective visualization strategy.

Students' Use of Web-Based Tutorial Materials and Their Understanding of Chemistry Concepts

This paper reports the findings of the initial phase of our study of student use of Web-based tutorial materials for general chemistry and student understanding of chemistry concepts. We found that students who use the Web site value this source of help and the visualization that the Web site offers. Some questions showed a tendency among women to be more positive than men toward use of the Web site, which may suggest value to using the Web to help female students learn chemistry. Our analysis of student understanding of chemistry concepts via concept maps indicated that students who used the Web site did not have as good an understanding of chemistry as the students who did not use it, but that Web users attempted to make more statements about the relevant chemistry concepts. Overall, most students thought that the Web was a good way to get help learning chemistry.

Molecular Science: Network-Deliverable Curricula

The Molecular Science systemic reform project, which has just begun its third year, is developing network-deliverable curricula for the first two years of Chemistry.1 The goals of the project are to prepare students who have a deep understanding of chemistry concepts and principles, have learned collaboration skills, can use the modern-technology tools of the chemist, and can write about chemistry. In addition, the project is integrating technology and telecommunications into the instructional process and shifting the instruction from lecture to active student learning. Faculty from six institutions (Crossroads School, East Los Angeles College, Pasadena City College, Mt. San Antonio College, California State University, Fullerton [CSUF], and the University of California, Los Angeles [UCLA]) form the core of the project. This cross-section represents the common and shared responsibility that exists for teaching the first two years of chemistry and the diversity of students in the nation.

The effects of computer animation on the particulate mental models of college chemistry students

AbstractModern chemistry concepts have the particulate nature of matter at their core. Chemists explain most phenomena in terms of atomic and molecular models. The lack of understanding of chemistry concepts may be linked to the students' inability to build complete mental models that visualize particulate behavior. With computer animation technology, dynamic and three‐dimensional presentations are possible. This study explores the effect of computer animations depicting the particulate nature of matter on college students' mental models of the chemical phenomena. A Particulate Nature of Matter Evaluation Test (PNMET) instrument was used to determine the nature of the students' visualizations and, therefore, their comprehension of the chemical concept studied. Animations were used in two treatment situations: (a) as a supplement in large‐group lectures, and (b) as both the lecture supplement and an assigned individual activity in a computer laboratory. These two experimental treatments were compared to a control group. Both treatment groups received significantly higher conceptual understanding scores on the PNMET than did the control group. This increased understanding may be due to the superiority of the formation of more expertlike, dynamic mental models of particle behavior in these chemical processes.

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

AbstractThe 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.