Students' understanding of selected phenomena in three school science topics : 'matter', 'solar system' and 'air and air pressure'

This study falls into the general category of research dealing with students' understandings of natural phenomena, particularly where this concerns so called 'pre-conceptions', 'misconceptions' and 'alternative frameworks'. An investigation was made of students' understanding of selected natural phenomena associated with three topics commonly taught in school science namely, 'matter and its forms', the 'Earth, Sun, Moon system' and 'air and air pressure'. A major purpose was to provide descriptions of students' understanding, in order to illuminate some of the problems of teaching and learning science in schools. Students' descriptions and explanations of the phenomena were obtained from an analysis of recorded clinical interviews of individual students, and from clinical-mode questionnaires administered to groups. Aspects of the lexicon and semantics of students' responses were studied in the light of normal science descriptions of those phenomena. The students participating in the study were from primary and lower secondary school grades in Tasmanian schools. However, in order to gain further insights into the linguistic implications for teaching and learning science, one of the studies, concerning 'matter and its forms', was replicated in an Asian cultural setting, in two different language speaking groups in the Philippines, with secondary school and college students. In order to establish a theoretical basis for the study, a brief account of some of the different descriptions of the nature of concepts is provided, with particular reference to current science education literature. Furthermore, so as to account for the contextual nature of science concepts, a taxonomy of science concepts has been developed, called a 'Scale of Empirical Distance' (SED), on which science concepts are mapped according to their degree of closeness to concrete realities. The scale uses two variables, namely, 'visual' and 'tactile', to generate four categories of science concepts on a continuum from concrete to abstract This Scale provided a rationale for the choice of topics used in the investigation of students' concepts, and acted as a frame of reference for generating insights about the data collected. These topics were selected because each one, overall, appeared to involve science concepts which were qualitatively different A range of alternative views, meanings for words, and explanations for the phenomena were found in each of the topics. Students' responses to questions about solid' and liquid forms of matter vary considerably according to the substance in question and students' grade level. Some students appear to use language registers which give scientifically correct answers from arguments based on alternative views, even for what might appear to teachers to be non-problematic exemplars. The study of ideas about the Earth, Sun and Moon focussed on shape, size and spatial relationships of those bodies. The spatial models, which appeared to be used by students to explain day and night and events during a year, can be grouped into a series of five distinct systems of increasing similarity to the currently accepted scientific model. Significant grade related differences were found in relation to the use of Sun-centred versus Earth-centred spatial models, as well as in the selection of correct shape, but not correct relative size of the bodies. Three common phenomena involving air and, or, water in enclosed spaces were used to explore students' reasons why water is retained or escapes from the spaces, and why a rubber cup sticks to some surfaces. Air was frequently believed to be the active agent to produce the observed effects and was invested with properties of space-filling, pushing, and also of pulling or sucking, when enclosed above liquids. The word pressure was used interchangeably with force and push. In the replication study, the responses of Tagalog and Ilocano speakers, from a common culture, are compared with responses of the Tasmanian students, and with each other, with regard to lexicon and inventories of alternative student perceptions. The social and linguistic differences between language groups are discussed in order to provide insights into the relationships between science concepts, language and culture. The findings of this study have significance for the teaching of science in schools. They highlight the need for teachers to listen more carefully to what students say, to respond constructively to their alternative perceptions, to be more aware and accepting of the dialectical nature of learning, and to be cognizant of the theoretical limitations of many fundamental classificatory schemes in science.