内容正文:
第8课时 圆锥的认识
圆柱与圆锥
3
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
优翼文化
二
探究新知
上面这些物体的形状有什么共同的特点?
优翼文化
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
这些物体的形状都是圆锥体,简称圆锥。
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
你还见过哪些圆锥形的物体?
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
拿一个圆锥形的物体,观察它有哪些特征。
顶点
底面
圆锥的底面是个圆。
1
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
侧面
圆锥的侧面是曲面,展开后是一个扇形。
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
O
h
r
高
从圆锥的顶点到底面圆心的距离是圆锥的高。
圆锥只有一条高。
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
怎样测量圆锥的高?
讨论
1.测量时,圆锥的底面要水平地放;
2.上面的平板要水平放在圆锥的顶
点上面;
3.测量。
二
探究新知
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
动手做一做
转动起来像一个圆锥。
如下图所示,把一张直角三角形的硬纸贴在木棒
上,快速转动木棒,看看转出来的是什么形状。
三
对应练习
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
www.youyi100.com
侧面
指出下面圆锥的底面、侧面和高。
底
面
侧面
底面
侧面
底面
高
高
高
做一做
优翼
四
巩固练习
www.youyi100.com
www.youyi100.com
www.youyi100.co