New Perspectives in Science Education

Energy changes in chemical reactions, is one of the topics that students struggle most to understand. Students have alternative models that comprise the relationships between the concepts of heat of reaction, change in internal energy and spontaneity. They have strong opinions about how an endothermic reaction cannot be spontaneous or that if a reaction is spontaneous then it is exothermic. Their experiences with chemical changes in their daily life support these ideas. The aim of this research is to identify perceptions about an endothermic and spontaneous reaction (NH4Cl + Ba(OH)2) that challenges the alternative models students have, to suggest a solution for creating the suitable model and to analyze their thinking processes in model creation. Both qualitative and quantitative research paradigms are used in conducting the study. The research group is constituted of the first year undergraduate students taking general chemistry lab course in the faculty of education of a state university in Turkey. The research had two phases. In the first stage, students (N:86) specified their hypotheses before they observed the reaction and they specified their conclusions after observing the reaction. This is done through a scale that consists of multiple choice and open-ended questions. Most of the students exhibited confirmation bias, they did not change their initial hypothesis and they looked for elements in the phenomenon to support their hypothesis. Students who changed their perspective were followed in the new model creation process and it was observed that they highly struggled in this process. In the second phase of the study the process of model creation of students (N:30), who attended a guided inquiry type experiment, was supported and examined. Students’ data explanation and model creation procedures were interfered with argumentation and scaffolding for reasoning. Students explained in writing their thinking process in creating the model, which explains the internal energy change based on the measurement of the decrease in system’s temperature. Written statements of students were analyses qualitatively. It was identified that in creating their new models, students use especially the cognitive processes of reasoning, imagination, analogical thinking.

Keywords: chemical energy, inquiry, creativity, mental model;

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