片断一:引入课件出示一个长方形小旗。师:这是什么图形?(长方形)如果以这条边所在的直线为轴,让它快速旋转,可以得到什么形体?(圆柱)多媒体出示生活中的圆柱实物。师:还能找出哪些物体是圆柱形状?生:奶粉罐、蚊香盒、水杯、火箭的中间一段。师:说得很准确,你在生活中还见到过哪些圆柱形状的物体?谁能再举个例子。生:我家的杯子、可比克的 Piece one: the introduction of courseware to produce a rectangular flag. Teacher: What is this figure? (Rectangle) What shape can I get if I rotate it with a straight line on the side of this side? (Cylinder) Multi-media shows the real objects in the cylinder. Teacher: Can also find out which objects are cylindrical shape? Health: milk cans, mosquito coils boxes, cups, rockets in the middle of a paragraph. Teacher: To put it precisely, what kind of cylindrical objects have you seen in your life? Can you give another example? Health: My family’s cup, Bik