“空气”是人教版九年级化学第二单元课题一,教学内容包括空气的组成、混合物和纯净物的概念以及空气中各成分的性质用途和空气的污染与保护。我把空气成分的探究作为了教学重点。导入:将一个内含白纸的小烧杯倒罩在盛水的水槽中,问:你们认为白纸会被水浸湿吗?为什么?学生回答:不会,因为烧杯中有空气。又问:怎么做可以让水进入杯中呢?学生答:将烧杯倾斜一些,放出一部分空气就可以了。我随后引入课题:今天我们一起研 “Air” is the second unit of the PEP teaching program. The teaching content includes the composition of air, the concept of mixture and pure substance as well as the nature and use of airborne components and air pollution and protection. I explored the composition of the air as a teaching point. Import: Place a small beaker of white paper in a water-filled sink and ask: Do you think the white paper will be soaked in water? Why? Student Answer: No, because there is air in the beaker. Q: How to make water into the cup? Student A: The beaker tilted some, release part of the air on it. I then introduced the subject: Today we study together