USING PHENOMENOGRAPHY COMBINED WITH KNOWLEDGE SPACE THEORY TO STUDY STUDENTS’ THINKING PATTERNS IN DESCRIBING AN ION

This study compares Hungarian 7th to 11th graders' thinking patterns in describing an ion. The combination of phenomenography and knowledge space theory was used as evaluation method to explore students' reasoning and to follow the change in students' cognitive structures. According to the phenomenographic analysis of the responses, three main categories, ‘ions are particles', ‘charge of ions' and ‘formation of ions', were identified. Connections between these categories were determined by adapting knowledge space theory to the hierarchy of categories. Results showed a typical shape of the process of conceptual change. The initial model for representation of students' knowledge structure is a simple one but during the instruction this model becomes more complex and finally ‘crystallises' the new model. In the initial model, the ‘charge of ions' category was independent of the ‘formation of ions' category, and these both categories were built on the category ‘ions are particles'. Significant change in connections among categories could be detected in 8th grade. From 8th grade the category ‘ions are particles' as basic knowledge was changed into the category ‘charge of ions'. At the end of the instruction (in 11th grade) – after mixing these models in 9th and 10th grades – a double model with basic category ‘charge of ions' was found for representation of students' thinking patterns in describing an ion.