论文部分内容阅读
“溶解”概念的建立,要通过实验操作进行观察,描述高锰酸钾在水中溶解的过程,进而通过想像,归纳形成“溶解”概念,又通过运用概念进行识别,加深学生对溶解概念的掌握。 在准备好了实验仪器(烧杯、搅拌棒、水槽等)和分组实验材料(食盐、高锰酸钾、砂子、白糖、碎石子、粘土、纯碱、小苏打、面粉等物)之后,我先抓了一小撮食盐,对学生说:“如果我把这一小撮食盐投入盛满水的烧杯里,然后用搅棒搅动,大家猜猜杯子里会出现什么现象?”就在学生猜测考虑的同时,我把食盐投入水杯然后搅动,学生们看到投入杯中的颗粒状的盐不见了,这时又问学生:“杯子里这时有没有食盐?”有的回答“没有。”有的回答“有。”我让学生说出各自的理由。回答“没有”的理由是:因为食盐在杯中不见了,我用搅棒蘸了一点杯中的水让学生尝尝,学生回答道:“水是咸的,证明水里有盐。”我
The establishment of the concept of “dissolution” should be observed through experimental operation to describe the process of potassium permanganate dissolution in water, and then through imagination, induction to form the concept of “dissolution”, and through the use of concepts to identify and deepen the students grasp of the concept of dissolution . After preparing the experimental equipment (beakers, stir sticks, sinks, etc.) and grouping the experimental materials (salt, potassium permanganate, sand, sugar, gravel, clay, soda ash, baking soda, flour, etc.) Caught a handful of salt, the students said: “If I put this handful of salt into a beaker filled with water, and then stirring with stirring stick, we guess what will happen in the cup?” Student speculation At the same time, I put the salt into a glass and stirred it. The students saw the salt dropped into the cup disappeared. Then they asked the student, “Is there any salt in the cup?” Some answered “No. Yes. ”I asked students to give their own reasons. The reason for answering “no” was that because the salt was missing in the cup, I dipped the cup of water with a paddler and let the students try it. The student replied: “The water is salty and it shows that there is salt in the water.” I