2024 Volume 65 Issue 1 Pages 107-118
The purpose of this study was to design a science class that incorporated explanatory activities in the “Chemical Changes and Ions” unit for the third grade of junior high school, and to verify its educational effectiveness through practice. To achieve this objective, we first designed and implemented a science teaching strategy that introduced dialogic activities by explaining and sharing ideas with other students in the third grade junior high school unit on “Chemical Changes and Ions”. We then analyzed the effects of explanation-based dialogue activities on the students’ understanding the concepts of acids and alkalis, based on the content of their descriptions of the true nature of acids and alkalis. We also analyzed the records of explanatory dialogue activities and students’ impressions of the lessons, and considered what kind of learning was developed during the explanatory dialogue activities. The results clarified the following characteristics of the method utilizing dialogue activities based on explanations and discussion: (1) By explaining to others, learners are encouraged to express evidence and construct contexts that relate them to arguments and results. (2) Through dialogue activities, learners are encouraged to use evidence that cannot be called scientific. This has the effect of making students aware of ambiguous parts of their own understanding, as well as encouraging students to review their own explanations by listening to others’ explanations, and, further, to encourage them to construct logic based on more valid evidence. (3) The activity encourages students to explain the true nature of acids and alkalis based on claims, evidence, and results, and effectively leads to sound conceptual understanding.
