Abstract
A major part of research interest in science education, especially in chemistry, is dedicated to the understanding of chemical concepts at the macro-, submicro- and symbolic level. The connectedness of all three conceptual levels is presented by the ITLS (Interdependence of Three Levels of Science concepts) model. This model served as the basis for a research problem with sixteen research hypotheses and a planned course of study.
The main purpose of the research was to establish how certain independent variables (demographic variables, gender, intrinsic motivation, visualisation and formal reasoning abilities, and educational strategies) are connected with the students’ understanding of the triple nature of chemical concepts. The correlations between the dependent and independent variables and the latent structure of the understanding of submicrorepresentation were established in the cross sectional study. A discriminative analysis of the complete set of manifested variables was also carried out with regard to the achievement of students in TSK (Test of Science Knowledge), the level of intrinsic motivation, achievement in school chemistry, and with regard to gender. On the basis of TSK scores the most frequent false and incomplete understandings of chosen chemical concepts were identified. Through interviews the possible reasons for the mistakes made in TSK were established. The basic characteristics of educational strategies employed by teachers, as well as the opinions gathered from students on the use of submicrorepresentations in chemistry lessons were also identified.
The research included a sample of 408 sophomore students of general type high schools. They were administered a series of tests and questionnaires. All metric characteristics of instruments were satisfactory.
TSK medium values show the students to be underachievers at all levels of chemical concepts. The poor results could be attributed to the fact that teachers mostly do not implement the ITLS model. Students believe the model would not only contribute to a better understanding of chemical phenomena, but would also make them more relevant. Intrinsic motivation reveals that in comparison with general study motivation and in comparison with other non-chemical intrinsic motivation components, the students are not highly motivated for chemistry. As for chemistry itself, the students are least motivated for the symbolic level, which is the level stressed most in chemistry classes, yet they are highly motivated for the experimental level.
The demographic variables and gender are not statistically significant in correlation to the understanding of chemical contents (pure substances and mixtures, chemical reaction, solutions, acids, bases and salts) at the examined ITLS model levels and their connections.
Although the academic achievement variables (general academic achievement, achievement in chemistry, physics and mathematics) are statistically significant, they are, however, not highly correlated to the general score in TSK, with the submicrorepresentation reading score, and there is no statistically significant correlation to the drawing of submicrorepresentations.
Intrinsic motivation is statistically significant but only slightly correlated to the understanding of chemical concepts.
From the intellectual abilities variables, the strongest and statistically most significant correlation to the TSK score is shown only by the formal reasoning ability. Visualization abilities are mostly not statistically significant in correlation to the TSK variables.
The latent structure of the first factor analysis of understanding submicrorepresentations is determined by ten factors that explain more than 78 % of the variance. The second factorisation offers a simpler structure. Three extracted factors are: (1) the cognitive abilities factor at the three ITLS model levels, (2) the intrinsic motivation factor of academic achievement, and (3) the conative abilities factor.
The discriminative analysis identified predicted variables that separate students with regard to: (1) the global TSK score, (2) motivation for chemistry, (3) achievement in chemistry, and (4) gender. The achievement in reading and drawing submicrorepresentations contributes most to the differentiation between high and low achievers in TSK testing. In all the discriminative analyses of motivation for chemistry, the students are differentiated on the basis of related types of intrinsic motivation for chemistry. The strongest discriminative element can be found in the variable of the motivation for the symbolic level. The third model of predictive variables shows that general academic achievement, motivation for chemistry and achievement in physics discriminate significantly between high and low achievers in chemistry. The strongest discrimination between the sexes is exhibited in the intrinsic motivation for physics and foreign languages. Thus, boys are more motivated for physics and girls for foreign languages.
Research results help us to predict that students will not be able to successfully solve problems based on the connections in understanding chemical concepts within the ITLS model unless teachers apply model components in their educational strategies. On the basis of already acquired experience they should be able to trigger in the students the cognitive conflict, which enables the elimination of already formed misunderstandings. Following this, they should actively apply the ITLS model and in this way develop new and for the student relevant connections between science concepts on all levels. The predictive variables model should help teachers to assist their students in developing a mental model of chemical concepts that would be based on the ITLS model. In the initial phase, the implementation of appropriate educational strategies would promote the reading of submicrorepresentations and, upon the evaluation of the students’ abilities for reading these, they could upgrade it with independent drawing of submicrorepresentations. Gradually, problems would be introduced that would require the students to apply higher cognitive abilities. The teachers should emphasise more the macroscopic and the submicroscopic components of chemical concepts. Considering the rather low correlations between the abilities of visualisation and the achievement in solving tasks based on the ITLS model, we can establish that even students with low visualisation abilities can successfully make the connections offered by the ITLS model in their working, and later in their long-term memory. These enable them to develop logical thinking and to make sense of abstract chemical concepts.
Key words
ITLS (Interdependence of Three Levels of Science concepts) model, submicrorepresentation, understanding chemical concepts, visualisation ability, formal thinking ability, intrinsic motivation, educational strategies
Correspondence
Dr. Iztok Devetak
University of Ljubljana
Faculty of Education
Department of biology, chemistry and home economics
Kardeljeva pl. 16
1000 Ljubljana
Slovenia
tel. +386(0)1 58 92 204
fax. +386(0)1 58 92 233 for Iztok Devetak
e-mail: iztok.devetak@pef.uni-lj.si
