教学目标1.使学生正确理解和掌握“二面角”、“二面角的平面角”的概念.2.引导学生探索和研究“二面角的平面角”应该如何定义,在概念形成的过程中,发展学生的思维能力.教学重点和难点重点:“二面角”和“二面角的平面角”的概念;难点:“二面角的平面角”概念形成的过程.教学过程设计一、问题引入问题情境1:如何刻画两个相交平面的相对位置?在平面里面我们用角来刻画两相交直线的相对位 Teaching Objectives 1. To enable students to correctly understand and master “dihedral angle ”, “dihedral angle of the plane ” .2 guide students to explore and study “dihedral angle of the plane ” should be Definition, the development of the concept of the formation of the process of thinking ability of students. Teaching emphasis and difficulties focus: “dihedral angle ” and “dihedral angle of the plane ”; difficult: “dihedral Plane angle ”process of the formation of the concept of teaching process design, problem introduction problem situation 1: how to characterize the relative position of the two intersecting plane? In plane we use the angle to characterize the relative position of the two intersecting lines