一、教学背景《圆的认识》是北师大版版小学六年级上册的内容,是在学生学过了几种平面几何图形的基础上进行教学的。学生已经学习过长方形、正方形、平行四边形、三角形、梯形等这些平面图形,圆与这些图形属于两类不同性质的图形,使学生对平面几何图形的认识,从直线段、图形扩大到曲线图形。虽然圆对于六年级学生来说是司空见惯的,但他们仅仅感知到圆这个图形的形状特征,并不认识圆内在的本质特征,也就是圆的结构特征。教材上要求学生认识圆 First, the teaching background “Circle of understanding” is the sixth grade of Beijing Normal University version of the primary volume of the content is based on the students learned a few plane geometry on the basis of teaching. Students have studied flat, square, parallelogram, triangle, trapezoid and other flat graphics. The circles and these graphics are two types of graphics with different properties. Students can learn about plane geometry from straight line segments and graphics to curve graphics. Although circles are commonplace for sixth graders, they only perceive the shape of the circle as a shape and do not recognize the intrinsic nature of the circle, the structural features of the circle. Textbooks require students to recognize the circle