地球の外から来た樹木 The Alien trees from outerspace. 木は水より軽いから浮くのが常識！ でも木は本当に軽いものばかりかな？ Normally, we think that pieces of wood are light so they can float on water. But it is true? It is not always the light ones that can float? 石は沈んで、木は浮かぶもの？ Do you think all stones will sink and all trees will float? ▼マウスをあててみよう！ 沈む木もある ▼On mouse here! Some of the trees will sink. 南洋の気候風土から育つ樹木の性質を考えます。