「理科の見方・考え方」を働かせた火成岩の学習

中学校理科において火成岩を扱う。中学生が火成岩を観察するとき，組織の識別ができないこと等の課題が指摘されている。その原因として，観察の視点とその意義（成因の考察）を理解していないこと，視点をもっていても技能的に困難であること等が考えられる。本研究は，前者の原因解決に向けた指導の改善を目的として，火成岩の分類を柱にした授業を計画して行った。共通点と相違点，原因と結果等の「理科の見方・考え方」を働かせる展開を導入することで，生徒に自ら観察の視点を獲得させたり，成因について疑問や課題をもたせたりすることができた。

This study provides some suggestions for the improvement of teaching the observation of igneous rocks in junior high school science lessons. In general, junior high school students appear to experience difficulty in identifying the organization of igneous rocks. Therefore, a lesson plan was conducted during which students decided on the scientific viewpoints and criteria to observe igneous rocks by themselves. During this lesson, students performed observations to compare several igneous rocks using scientific viewpoints and ways of thinking. The results showed that the students were able to obtain scientific viewpoints to observe ingenious rocks by themselves. Furthermore, the students were able to have some questions and find tasks towards identifying factors that affect the formation of igneous rocks.