一、教材分析“旋转”是新课标实验教材新增加的内容。九年义务教育苏教版实验教科书在三年级下册和四年级下册两次安排这一内容。首次安排图形的旋转讲的是对旋转的初步认识,如风扇叶片、飞机上的螺旋桨、机械钟摆的旋转等。本次安排的旋转内容具有一定的抽象性,学生通过对两道例题的操作与探究,认识了旋转的“三要素”。学好这部分知识不仅对帮助学生建立空间观念、掌握变换的 First, the textbook analysis “rotation ” is the new content of the new curriculum standard experimental teaching materials. The nine-year compulsory education Supayan edition of experimental textbooks in the third grade and the fourth grade under the two arrangements for this content. The first scheduled rotation of the graphic is a preliminary understanding of rotation, such as fan blades, propellers on an airplane, rotation of a mechanical pendulum and the like. The content of the rotation of this arrangement has a certain degree of abstraction. Through the operation and exploration of the two examples, students recognize the “three elements” of rotation. Learn this part of the knowledge not only to help students to establish the concept of space, master the transformation