ダニエル電池の包括的理解を支援する発展授業 : セパレータに着目した比較実験とクラスでの議論の効果

In this study, an open-ended questionnaire was used to determine the current state of understanding of chemical batteries among junior high school students who are beginning electrochemistry, and to investigate the effects of comparative experiments and whole-class discussions on students’ understanding as a developmental lesson. By the end of the standard class required of third-year junior high school students under the Courses of Study, the majority of students had formed correct concepts of the oxidation reaction at the anode, the transfer path of electrons generated, and the reduction reaction at the cathode in relation to the Daniell cell. On the other hand, the role of the separator (ion transfer pathways, electrolyte neutrality, and electrolyte mixing) was not found in almost all students’ descriptions. As a developmental lesson, a comparative experiment on separators was conducted, and students tended to consider ion migration and electrolyte neutrality. Further whole-class discussion reinforced these tendencies and showed that students began to notice that the separator prevented the electrolyte from mixing. Regarding the driving force of the reaction, the frequency of its occurrence in the students’ descriptions decreased after repeated questionnaires, suggesting the need for continued support by teachers. In conclusion, we found that a separator comparison experiment and whole-class discussions were effective in helping students understand the comprehensive operating principles of chemical batteries.