Hans‐Jürgen Schmidt

A label as a hidden persuader: chemists’ neutralization concept

The original meaning of neutralization has shifted in the course of its 300‐year development. As chemistry teaching deals with both the old and new definitions, one can assume that students are liable to have difficulties in applying the concept correctly. The aim of this study has been to identify and describe the problems students have with the concept of neutralization. About 7500 students were randomly assigned test items referring to the concept of neutralization. Analysis of the answers showed that many students understand the concept in its original meaning. They assumed that in any neutralization reaction a neutral solution is formed, even if a weak acid or base takes part in the reaction. Other students came to the same conclusion assuming that neutralization is an irreversible reaction. Not until the students realize that two reactions have to be taken into account, can they understand what happens when, for example, a weak acid reacts with a strong base. These are the two equilibrium reactions:...

Quality criteria and exemplary papers in chemistry education research

There has been a discussion about quality criteria in chemistry education research in the scientific community. This paper is based upon the idea that the values prevailing in research are reflected in the criteria that are suggested and used to judge research papers. Two research questions were addressed: what are the quality criteria of research in chemistry education; and in what ways do exemplary papers meet quality criteria? The quality criteria were ascertained from the literature. Exemplary papers to illustrate the criteria were selected from a sample of 81 research papers published in JRST and IJSE 1991-1997. The result was a list of criteria subsumed in six categories. Five exemplary studies were chosen to illustrate the criteria. The criteria are discussed in terms of underlying values. This paper contributes initial ideas and intends to trigger a discussion of quality criteria in chemistry education research.

Applying the concept of conjugation to the Br⊘nsted theory of acid‐base reactions by senior high school students from Germany

Abstract The purpose of this descriptive study was to identify misconceptions held by German senior high school students about the Br⊘nsted acid‐‐base theory. Test items were developed that can be used to uncover student problems in this area. A sample of 4291 senior high school students in grades 11‐13 completed paper‐and‐pencil tests on acid‐‐base theory. Discussions in individual classes were videotaped while the students solved test questions. The results indicate that German senior high school students have two misconceptions about conjugate acid‐‐base pairs. First, they confuse non‐conjugate and conjugate acid‐‐base pairs. One possible explanation for this is that the distinction between the two associations is seldom mentioned in US and German chemistry textbooks. Second, students regard pairs of positively and negatively charged ions as conjugate acid‐‐base pairs as if they somehow neutralized each other. Students use chemical terminology, but misconceptions occur because the terminology is mislea...

Textbooks’ and teachers’ understanding of acid-base models used in chemistry teaching

Acid-base reactions can be described in several ways: by formula equations as reactions between substances, or by ionic equations as proton transfer reactions according to Bronsted‘s model. Both models are introduced in chemistry teaching at Swedish secondary schools. The aim of this study was to determine how textbooks and teachers handle the different models to explain acid-base reactions. First, chemistry textbooks most widely used in Swedish upper secondary schools were examined. Second, semi-structured interviews were conducted with six chemistry teachers. The textbooks neither described the differences between the models used to explain acid-base reactions nor clarified why the Bronsted model was introduced. Teachers were well aware of the importance of using models in their lessons. However, they seemed to have difficulties in applying this view with respect to acids and bases. There was no clear distinction between the models, some teachers had even not reflected on the differences between them. They seemed to rely on the content of chemistry textbooks. Implications for textbook writers, teachers and further research are discussed. [Chem. Educ. Res. Pract., 2005, 6 (1), 19-35]

Secondary school students’ strategies in stoichiometry

This study was designed (1) to analyse the relationship between the answer profile from multiple‐choice questions on stoichiometric problems and the students’ reasoning patterns and (2) to examine the effect for certain variables on the facility values of test items. The instruments used were mainly paper‐and‐pencil tests. The subjects were 6262 grammar school students from all parts of the Federal Republic of Germany. They were randomly assigned to the test items. The results indicated that many students arrived at their answers by mixing up amount and reacting mass, or molar mass and reacting mass. It was also found that the variables ‘easy/hard calculations’, and ‘formula given/to be developed’ determined the facility values of test items. From the results, it was possible to make recommendations to practising teachers as well as to examiners. Knowing students’ ideas, the teacher can think of how to make use of them before entering the classroom. A teaching unit may start off with easy problems leaving...

Students’ understanding of boiling points and intermolecular forces

In introductory chemistry courses students are presented with the model that matter is composed of particles, and that weak forces of attraction exist between them. This model is used to interpret phenomena such as solubility and melting points, and aids in understanding the changes in states of matter as opposed to chemical reactions. We investigated upper secondary school students’ models for intermolecular forces and their abilities to use these for predicting the relative boiling points of organic compounds. Written tests were administered to students in grades 11 to 13 (aged 16 to 19) in Germany. Students’ answers, and especially the reasons they gave for their answers, were analysed. Results indicate students had difficulty predicting the relative boiling points of organic compounds. The most prominent alternative conception was that boiling involves breaking covalent bonds. Results also indicate that students used alternative models for hydrogen bonds, limiting the occurrence of hydrogen bonds to the presence of oxygen and hydrogen atoms, or to dipolar molecules. The results show that the understanding of intermolecular forces in upper secondary school is inadequate, and that teaching should be changed. The items developed in this study could be incorporated into classroom discussions.

An Alternate Path To Stoichiometric Problem Solving.

Stoichiometric problem solving has always been a stumbling block for many students in introductory chemistry courses. Research has shown that it is quite common for students to rely on algorithms when doing stoichiometric calculations. In previous studies, students were confronted with simple stoichiometric problems that involved comparing molar masses with simple ratios to one another. It turned out that students very successfully used their own problem-solving strategies. It is typical of these strategies that students describe relations in their own words rather than applying mathematical calculations. In this paper, an alternate path to teaching introductory stoichiometry-based on the results of research-will be discussed. The recommendation given is to use problems of the kind mentioned above which can easily be solved by quick mental calculation.

GROUP DISCUSSIONS AS A TOOL FOR INVESTIGATING STUDENTS' CONCEPTS

Learning chemistry, i.e. acquiring and changing chemical concepts, is a complex process. Investigating these processes is a complex task. Therefore, a variety of methods is necessary to provide relevant research results. The present paper explores the possibility of conducting discussions with entire chemistry classes in such a way that students are given a stronger role. The investigation tries to develop a structure for group discussions, guidelines for the role of the host as well as for the analysis of the discussions, and examples for stimuli that give students ample opportunity to discuss chemical concepts. To develop the method, a cyclical research design was adopted. Six groups of high school students participated. The discussions were videotaped and discussed within the team of researchers. The results are a number of principles for the structure of group discussions, for the role of the host, the tasks presented to the participants and the analysis of the videotaped discussions. The principles are illustrated using examples from the discussions. It emerged that students are ready to talk about chemical problems. In the discussions they focused on their interests in a particular field. The group discussion is an open, dynamic and self organising process. Further research can show whether this method also works in other situations. Researchers are encouraged to transfer our principles and guidelines to new topics and to continue refining them. It is also suggested to use group discussions in teacher training. [Chem. Educ. Res. Pract., 2004, 5, 265- 280]

QUALITY CRITERIA FOR RESEARCH PAPERS ON SCIENCE EDUCATION: HOW CAN THEY BE USED TO IMPROVE MANUSCRIPTS SUBMITTED FOR PUBLICATION?

This contribution to the conference describes a workshop on quality criteria for research papers in science education. The activities and the outcomes of the workshop are reported, including its concise evaluation and some suggestions for manuscript improvement. [Chem. Educ. Res. Pract. Eur.: 2000, 1, 27-30]