课前思考“求不规则物体的体积”是人教版《数学》五年级下册的内容。因为生活中有许多不规则的物体,怎样求它们的体积是本课重点要探究的内容。这部分知识是在学生学习了规则的长方体和正方体体积、容积之后进行的,内容安排上符合学生的认知规律。教材中通过用“排水法”测量雪花梨的体积,使学生明确求不规则物体的体积可以用“排水法”进行测量,上升那部分水的体积就是不规则物体的体积。目的是培养学生对知识的转化、迁移的能力,会用化归思想方法 Thinking before class “seeking the volume of irregular objects ” is the content of the fifth edition of the fifth grade of the PEP. Because there are many irregular objects in life, how to find their volume is the focus of this lesson to explore. This part of the knowledge is learned after the students learn the rules of the cuboid and cube volume, volume, content arrangement in line with the cognitive rules of students. Teaching materials by measuring the volume of Snow pear with “Drainage ”, so that students can clearly find the volume of irregular objects can be measured by “drainage method ”, the volume of that part of the water is the volume of irregular objects. The purpose is to cultivate students’ ability to transform and transfer knowledge, and to use the method of thinking