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.