A. L. Chandrasegaran

The development of a two-tier multiple-choice diagnostic instrument for evaluating secondary school students’ ability to describe and explain chemical reactions using multiple levels of representation

A 15-item two-tier multiple-choice diagnostic instrument was developed to evaluate secondary students’ ability to describe and explain seven types of chemical reactions using macroscopic, submicroscopic and symbolic representations. A mixed qualitative and quantitative case study was conducted over four years involving 787 Years 9 and 10 students (15 to 16 years old). The instrument was administered to sixty-five Year 9 students after nine months of instruction to evaluate their use of multiple levels of representation. Analysis of the students’ responses demonstrated acceptable reliability of the instrument, a wide range of difficulty indices and acceptable discrimination indices for 12 of the items. The teaching program proved to be successful in that in most instances students were able to describe and explain the observed changes in terms of the atoms, molecules and ions that were involved in the chemical reactions using appropriate symbols, formulas, and chemical and ionic equations. Nevertheless, despite the emphasis on multiple levels of representation during instruction, 14 conceptions were identified that indicated confusion between macroscopic and submicroscopic representations, a tendency to extrapolate bulk macroscopic properties of substances to the submicroscopic level, and limited understanding of the symbolic representational system. [Chem. Educ. Res. Pract., 2007, 8 (3), 293-307.]

An Investigation into the Relationship between Students' Conceptions of the Particulate Nature of Matter and their Understanding of Chemical Bonding

A thorough understanding of chemical bonding requires familiarity with the particulate nature of matter. In this study, a two‐tier multiple‐choice diagnostic instrument consisting of ten items (five items involving each of the two concepts) was developed to assess students’ understanding of the particulate nature of matter and chemical bonding so as to identify possible associations between students’ understandings of the two concepts. The instrument was administered to 260 Grades 9 and 10 students (15–16 years old) from a secondary school in Singapore. Analysis of students’ responses revealed several alternative conceptions about the two concepts. In addition, analysis of six pairs of items suggested that students’ limited understanding of the particulate nature of matter influenced their understanding of chemical bonding. The findings provide useful information for challenging students’ alternative conceptions about the particulate nature of matter during classroom instruction in order to enable them to achieve better understanding of chemical bonding.

The Taiwan National Science Concept Learning Study in an International Perspective

Over the past two decades, several two‐tier multiple‐choice diagnostic tests in science at a variety grade levels have been reported in the extant literature from several countries. This review summarises these studies, provides an overview of the methodology for their construction, presents two examples of typical items, and lists studies published with two‐tier tests. The majority of these studies have been conducted with relatively small numbers of students in one school, college, or university, although there are exceptions. What distinguishes the research reported in the articles in this Special Issue is that the Taiwanese two‐tiered tests for the National Science Concept Learning Study were designed to identify the scientific conceptions of students from large national samples using random sampling procedures similar to those found in studies such as Trends in Mathematics and Science Studies and Programme for International Student Assessment. The article concludes with implications for the use of two‐tier tests for pedagogical practice and research.

A stratified study of students’ understanding of basic optics concepts in different contexts using two‐tier multiple‐choice items

A large scale study involving 1786 year 7–10 Korean students from three school districts in Seoul was undertaken to evaluate their understanding of basic optics concepts using a two‐tier multiple‐choice diagnostic instrument consisting of four pairs of items, each of which evaluated the same concept in two different contexts. The instrument, which proved to be reliable, helped identify several context‐dependent alternative conceptions that were held by about 25% of students. At the same time, students’ performance on the diagnostic test correlated with the location of the schools, students’ achievement in school science and their attitudes to science learning. However, students’ grade levels had limited influence on their understanding of basic concepts in optics as measured by the instrument.

Students' Dilemmas in Reaction Stoichiometry Problem Solving: Deducing the Limiting Reagent in Chemical Reactions

A qualitative case study was conducted to investigate the understanding of the limiting reagent concept and the strategies used by five Year 11 students when solving four reaction stoichiometry problems. Students’ written problem-solving strategies were studied using the think-aloud protocol during problem-solving, and retrospective verbalisations after each activity. Contrary to several findings reported in the research literature, the two high-achieving students in the study tended to rely on the use of a memorised formula to deduce the limiting reagent, by comparing the actual mole ratio of the reactants with the stoichiometric mole ratio. The other three average-achieving students, however, generally deduced the limiting reagent from first principles, using the stoichiometry of the balanced chemical equation. Overall, the students displayed limited confidence during problem-solving to determine the limiting reagent and to perform related computations.

Relationship Between Affect and Achievement in Science and Mathematics in Malaysia and Singapore

Background : The Trends in International Mathematics and Science Study (TIMSS) assesses the quality of the teaching and learning of science and mathematics among Grades 4 and 8 students across participating countries. Purpose : This study explored the relationship between positive affect towards science and mathematics and achievement in science and mathematics among Malaysian and Singaporean Grade 8 students. Sample : In total, 4466 Malaysia students and 4599 Singaporean students from Grade 8 who participated in TIMSS 2007 were involved in this study. Design and method : Students’ achievement scores on eight items in the survey instrument that were reported in TIMSS 2007 were used as the dependent variable in the analysis. Students’ scores on four items in the TIMSS 2007 survey instrument pertaining to students’ affect towards science and mathematics together with students’ gender, language spoken at home and parental education were used as the independent variables. Results : Positive affect towards science and mathematics indicated statistically significant predictive effects on achievement in the two subjects for both Malaysian and Singaporean Grade 8 students. There were statistically significant predictive effects on mathematics achievement for the students’ gender, language spoken at home and parental education for both Malaysian and Singaporean students, with R 2 = 0.18 and 0.21, respectively. However, only parental education showed statistically significant predictive effects on science achievement for both countries. For Singapore, language spoken at home also demonstrated statistically significant predictive effects on science achievement, whereas gender did not. For Malaysia, neither gender nor language spoken at home had statistically significant predictive effects on science achievement. Conclusions : It is important for educators to consider implementing self-concept enhancement intervention programmes by incorporating ‘affect’ components of academic self-concept in order to develop students’ talents and promote academic excellence in science and mathematics.

The Efficacy of an Alternative Instructional Programme Designed to Enhance Secondary Students’ Competence in the Triplet Relationship

Research has consistently shown that secondary school students have conceptual difficulties transferring between macroscopic, submicroscopic and symbolic representations in chemistry. In this chapter, we describe how students responded to a 15-item two-tier multiple choice diagnostic instrument that analysed their understanding of seven types of chemical reactions using macroscopic, submicroscopic and symbolic representations after they had been taught a special alternative programme to make these three representations more overt. The research has shown that by placing particular emphasis on the triplet relationship of macroscopic, submicroscopic and symbolic representations in chemistry, it is possible for students to achieve more meaningful learning of chemical representations. Suggestions are made for how such improved learning can be accommodated in normal classrooms, as compared to research-oriented classrooms.

Assessment of electrochemical concepts: a comparative study involving senior high-school students in Indonesia and Japan

Background and purpose This study investigated Indonesian and Japanese senior high-school students’ understanding of electrochemistry concepts. Sample The questionnaire was administered to 244 Indonesian and 189 Japanese public senior high-school students. Design and methods An 18-item multiple-choice questionnaire relating to five conceptual categories (reactions occurring during electrolysis, differences between electrolytic and voltaic cells, movement of ions in voltaic cells, poles in voltaic cells, voltaic cell reactions) was administered. Results The findings of this study show that difficulties and alternative conceptions previously reported in the literature are held equally by students from a developing and developed country, Indonesian and Japan respectively. Conclusions Collectively, the findings suggest that students’ understanding of electrochemistry concepts is relatively weak. Students from both samples shared common difficulties and displayed several alternative conceptions dealing with electrolysis, electricity flow, the voltaic cell and the electrode reactions. Not surprisingly, the students displayed limited consistency in understanding of the concepts in the five categories. This study has implications for teaching and learning, particularly in classroom discussions using models and computer animations in order to reinforce understanding at the sub-microscopic level.

Kinetics of acid reactions: making sense of associated concepts

In chemical kinetics, in addition to the concepts related to kinetics, stoichiometry, chemical equilibrium and the characteristics of the reactants are often involved when comparing the rates of different reactions, making such comparisons very challenging for students at all levels, as well as for pre-service science teachers. Consequently, four multiple-choice items were developed to determine the understanding of 217 pre-service science teachers of the kinetics of acid reactions that are taught at the Grade 9 to 10 levels in Singapore schools. Each of four items compared two different acid reactions under similar conditions, and respondents were required to select the best graphical representation for the two reactions. Respondents were also required to provide reasons to explain their particular selection for each item. In addition, one item on the dissociation of sulfuric acid and two items involving excess/limiting reagents were also included to provide additional data on the pre-service teachers’ understanding of these concepts that were assessed in the four items on kinetics of acid reactions. The results showed that the pre-service teachers had difficulties in explaining the properties of different common acids, including the dissociation of the acids and how these affect the rates of the different acid reactions. This study highlights the importance of determining pre-service teachers’ understanding of the concepts that they will be teaching with a view to addressing areas of difficulty, as these will have consequences on their future students’ learning.

Second-Year College Students’ Scientific Attitudes and Creative Thinking Ability: Influence of a Problem-Based Learning (PBL) Chemistry Laboratory Course

This research examined the effects of a problem-based learning (PBL) chemistry laboratory course for second-year college students (N = 20) on students’ scientific attitudes with an emphasis on their creative thinking abilities. The findings were contrasted with a traditional laboratory course (N = 26) to elucidate any differences in the influence of the courses. Only female students participated in the study which was conducted in a private university for women in Korea. A 20-item Scientific Attitudes Questionnaire administered to both groups as a pretest and a posttest revealed that there were significant changes in criticism, cooperativeness, and creativity at the end of instruction only among students in the PBL course. The posttest scores of the Torrance Tests of Creative Thinking to gauge students’ creative thinking ability were significantly higher for the students in the PBL course on all three dimensions. The research suggests that PBL laboratory courses in chemistry have great potential to positively change students’ scientific attitudes towards learning chemistry and enhance their creative thinking abilities.