今天是周一,同学们陆续地回到学校。他们书包里面装着的除了这一周需要换洗的衣服外,就是那一大兜诱人的零食了。因为天气炎热,又怕挤压,张珊的妈妈这次给她准备的都是一些像蛋黄派、薯片等充气包装的食品。在宿舍整理物品的时候,一个同学突然提问:“这些包装袋内装的是什么气体呢?”这个问题引起了同宿舍几个姐妹的好奇,以前也经常吃这些充气包装的食品,却从来都没有考虑过包装袋内的气体是什么。因为她们刚刚学习了《我们的空气》这一单元,对空气及其成分已经有了一个初步的认识。“那这包装袋 Today is Monday, the students came back to school one after another. Inside their school bag, except for the clothes that need to be changed this week, there is an attractive treat for the big bag. Because of the hot weather, afraid of extrusion, Zhang Shan’s mother to her this time are some like yellow pie, potato chips and other inflatable food packaging. When arranging items in the dormitory, a classmate suddenly asked: ”What gas is contained in these bags?“ This issue caused curiosity in the dorm with several sisters, and in the past often used to eat these inflatable foods, but never Have not considered the gas inside the bag is what. Because they have just learned about the ”our air“ unit, there is already a basic understanding of air and its components. ”Then this bag