複数の種類の金属を用いて金属の性質をとらえる授業開発 : 第4学年「物のあたたまり方」の実践を通して

本研究の目的は，熱伝導率の視点から金属それぞれの性質をとらえさせるとともに，帰納的に金属共通の性質を導く意味を考えさせる授業開発を行い，学習内容を考察することである。小学4年生「物のあたたまり方」の単元において授業開発・実践を行った後，質問紙調査への回答から考察した。その結果，金属は種類によって熱の伝わる速さが異なることに子ども自ら気づき，熱伝導率の視点から金属それぞれの性質を明らかにすることができた。また，金属のあたたまり方の実験において銅を用いた理由について熱伝導率を根拠にして説明することができた。一方，帰納的に一般化するため，複数の種類の金属を用いることについては，子どもたちにその必然性を持たせる授業展開の仕方に課題が見られた。今後は，実験に金属を用いる単元において，金属は種類によってさまざまな性質が異なることを丁寧に指導する必要があると考える。

The aim of this study is following two. The first aim is to develop classes from following two aspects; let children understand qualities of each metal from the perspective of thermal conductivity, and make children think about the meaning of inductively drawing the qualities that are common to these metals. The second aim is to investigate contents of those learning practices. The class was developed and conducted in the unit on "how things are heated" at the fourth grade of an elementary school. The class was then investigated through the answers on a questionnaire. As a result, children have noticed by themselves that how fast the heat transmitted varied with the kinds of metal, and they have managed to reveal qualities of each metal from the perspective of thermal conductivity. Children were also able to explain why they used copper in the experiment on how metals were heated based on thermal conductivity. On the other hand, problems to be solved were observed in how to develop classes that children would have understood the necessities of using several kinds of metal in order to inductively generalize its quality. In the future, teachers will be required to instruct clearly and in detail that different kinds of metal possess different qualities within the class units that use metals in the experiments.