教学内容:画圆,认识半径、直径,以及半径与直径的关系。教材分析:学生在第一学段已经直观地认识了圆。本课是在这个基础上进一步学习圆的知识。圆形和学生已经学过的长方形、正方形、三角形、平行四边形、梯形等平面图形一样大量存在于我们的生活当中,但它们都是线段围成的图形,而圆是曲线围成的,这也是学生研究曲线图形的开始,是学生认知的一次较大飞跃。因此, Teaching Content: Draw a circle, understand the radius, diameter, and the relationship between radius and diameter. Textbook Analysis: Students have intuitively recognized the circle in the first semester. This lesson is based on the further study of the circle of knowledge. Circles, such as rectangles, squares, triangles, parallelograms, trapezoids and other planar graphics that students have already learned, exist in our lives as much, but they are all lines enclosed by curves, and the circles are curvilinear, which is also Students study the beginning of the curve graphics is a big leap in student cognition. therefore,