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1、人教版小学数学二年级上册说课稿 轴对称图形教学内容:义务教育课程标准实验教科书第5661页，轴对称图形 教学目标: 1、联系生活中的具体物体，通过观察和动手操作，使学生初步体会生活中的对称现象，认识轴对称图形。 2、使学生能根据轴对称图形的初步认识，在实物图案和平面图形中识别轴对称图形，能用一些方法做出轴对称图形，能在方格纸上画出简单的轴对称图形。 3、使学生在认识和制作简单的轴对称图形的过程中，感受到物体或图形的对称美。激发数学学习的兴趣。 教学重点: 轴对称图形的初步认识和制作。 教学难点: 轴对称图形的初步认识。 教学准备:多媒体课件、实物投影仪、剪刀、彩纸、图形纸、钉子板、字母卡片等。
2、 教学过程 一、猜一猜情景导入 1:欣赏录像。(课件出示春天到北京旅游的景象) 二、观察、操作探究特征 1、观察，初步感知 (1)认识对称 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties red
3、uced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying
4、 degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled
5、 addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce t
6、he mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter constru
7、ction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 观察照片，你能发现它们有什么特点吗,(师课件点击放大剪纸图。) 生:它的两边都是一模一样的。 (课件点击返回)那其它物体有没有两边也是一模一样的呢, (2)揭示对称 像这样物体的两边是一模一样的，我们就说这个物体它是对称的。那这些物体它们都是对称的。 (3)扩展认识 在生活中你还见过哪些物体也是对称的呢,(课件出示)和你的
8、同桌说一说。 (同桌之间自由说，全班交流) 2、操作，体会特征 (1)从物体到图形的认识 把这些对称的物体画下来，得到下面的图形:(电脑出示按天安门、飞机、奖杯、蝴蝶等实物画下来的图形) 继续观察，这几个图形有什么特点呢, 任选一个图形，在小组内合作，尝试能用什么方法来验证它 们是对称的呢, (学生操作，教师巡视，选择不同的实验方法。) 交流反馈。演示折纸过程:对折后两边是对称的 板贴:对折 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following m
9、easures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature differe
10、nce cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water
11、 temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives mu
12、st be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation
13、 to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 师:那再请同学们观察一下，你把图形对折后发现了什么呢,在小组里说一说
14、。(学生小组交流) 生:它们对折后两边是对称(一模一样)的。 师:那其他图形也是这样的吗,师加以补充:像这样，对折后折痕两边的部分完全一样(对称)，称为完全重合。板贴:完全重合 师:为了使大家看得更清楚，我们请电脑老师来演示一下。(电脑演示:2个对折完全重合的过程)。请大家把其余的两个图形再折一折，你发现了什么,(学生操作，小组交流述说) 师:这些图形它们有什么共同的特征呢,(点名回答) 生:它们对折后两边是能完全重合的。 小结:像这样，对折后两边能完全重合的图形是轴对称图形(板帖:轴对称图形的概念) 师:今天我们就要来学习轴对称图形(板贴课题:轴对称图形) 师:这些图形都是(学生讲轴对称图形
15、)，那谁来说说这三张图形为什么是轴对称图形呢, 生:(点名回答)它们对折后能完全重合，所以是轴对称图形。 师:如果把刚才对折后的图形打开来看看，还发现什么呀, 生:一条折痕。 师:有一条折痕。这条折痕就是这个图形的对称轴。(电脑演示对称轴)(板贴:对称轴) 师:你能找出另外两张图形中的对称轴吗,相互说一说。(同桌交流) summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in s
16、ummer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high t
17、emperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix pro
18、portion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by th
19、e supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and coveri
20、ng thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 师:(小结)现在同学们知道什么图形才是轴对称图形吗,在小组里交流一下(小组交流) 3、识别，加深体验动手操作 师:同学们的表现真不错。今天，一
21、些图形娃娃也非常高兴来参加我们的活动，但它们有个要求(电脑出示P57“试一试”)要请同学们运用这节课所学的知识找出哪些是轴对称图形,大家能满足图形娃娃的要求吗,组长拿出信封中的图形，选择自己喜欢的图形动手折一折，然后在小组里说一说你选的是轴对称图形吗,为什么,(小组合作操作) 师:(点名回答)三角形是轴对称图形吗,为什么, (点名回答，学生投影展示) 师:那平行四边形是轴对称图形吗,为什么 (点名回答并投影展示) 师:(小结)通过刚才的操作，同学们知道怎样的图形才是轴对称图形吗, 生:(请23名学生说) 4、训练，巩固特征 师:看来同学们学得真棒啊下面吴老师呢就要来考考大家了。 (1)师:(课
22、件出示第58页第1题)这是我们生活中常会看到的一些图形，你能一眼就看出它们中哪些是轴对称图形吗,(直接提问，课件演示12个是轴对称图形，对有疑问的再演示) (2)师:同学们知道吗，我们学的英文字母，有很多也是轴对称图形呢就让我们在抢答游戏中把它们找出来吧，看谁的反映最快。(教师举字母卡片，学生抢答) summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high
23、 temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperature
24、s, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of
25、 concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervis
26、ing engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-fi
27、lm wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into (3)师:(小结)为什么N、S不是轴对称图形呀, 生:(上来动手折一折)因为它们对折后不会完全重合。 师:所以轴对称图形一定要对折后能完全重合。(学生一起说) 三
28、、做一做内化新知 (1)教学例2做轴对称图形 师:刚才我们认识了轴对称图形，那大家想不想自己动手来做一个呢,请组长拿出信封中的材料，小组合作，各显神通吧，看哪个小组制作的轴对称图形最美了。(小组合作设计，教师巡视) 师:谁来把你的作品给大家展示一下呢, (请2种不同的方法到实物投影上展示，讲讲他们的做法) 师:(小结)看来同学们的方法可真多呀，我们做出来的轴对称图形对折后能(学生讲完全重合)(教师在实物投影上演示，并把一些学生的作品贴在黑板上) (2)师:昨天吴老师也剪了几个轴对称图形，(电脑出示P59第4题)下面的图案各是从哪张纸上剪下来的，你能连一连吗,请同学们把书翻到第59页，在书上完成
29、。(学生独立完成，再点名回答，电脑相机演示连线) 四、全课总结 师:今天，我们认识了轴对称图形，通过这堂课的学习，大家有什么收获呢,把你学到的本领告诉你的小组同学。 (学生小组交流，再点名回答) (对折后能完全重合的图形是轴对称图形，对折后的折痕所在的直线叫做对称轴，还学会了做轴对称图形。) summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high tem
30、perature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, d
31、ue to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of con
32、crete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising
33、engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film w
34、et grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials, equipment, planning ahead of time comes into 五、巩固练习 (1)师:同学们的收获可真大啊那国旗是一个国家的象征，每个国家都有国旗，大家知道我国的国旗吗,(电脑出示P59第5题)你能在下面一些国家的国旗中，找出哪些是
35、轴对称图形吗,我们用手势来表示，如果是轴对称图形就用*表示，如果不是轴对称图形你就摇摇手，明白吗, (全班学生一起用手势表达，老师在电脑上演示) (2)师:刚才我们认识了那么多的轴对称图形，那同学们想不想自己来画一个轴对称图形呢,(电脑出示P58想想做做3)画出下面每一个图形的另一半，使它成为一个轴对称图形 (翻开书到P58，学生独立在书上完成，再电脑演示，做对的举手) 六、看一看拓展延伸 师:轴对称图形以其特有的对称美，给人们带来了一种和谐的美感，古今中外，有许多着名的建筑也是对称的，让我们一起来看看这些对称的建筑，感受它们的奇妙和美丽(电脑配乐欣赏着名的建筑图片) 师:生活中的对称现象还有
36、很多很多，有兴趣的同学课后还可以到雅虎、百度网站去查阅一些有关轴对称图形的资料，和同学交流一下。 教学反思: 本课是六年制小学数学第二学段空间与图形中的学习内容，教学重点是使学生初步认识轴对称图形的一些基本特征，难点是掌握判别轴对称图形的方法。在此之前学生已经学过一些平面图形的特征，形成了一定的空间观念，自然界和生活中具有轴对称性质的事物有很多，也为学生奠定了感性基础。这是一堂集欣赏美与动手操作为一体的综合实践课，为了更有效地突出重点，突破难点，按照学生的认知规律，遵循教师为主导，学生为主体，训练为主线的指导思想,因此，本课的教学设计力求体现:数学问题生活化，注重培养学生观察、交流、操作、探究
37、能力的培养，让学生充分经历知识的形成过程，在教学过程中建构具有教育性、summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced bleeding, fast drying, easy to
38、 crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees, on mixing processes, perf
39、usion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition of retarder agent can red
40、uce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing time and shipping time at
41、 high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter constructi
42、on preparation 1) required winter construction materials, equipment, planning ahead of time comes into 创造性、实践性、操作性的学生主题活动为主要形式，以鼓励学生主动参与、主动探索、主动思考、主动实践为基本特征，以学生的自主活动和合作活动为主。 纵观这节课的教学过程，课堂教学模式发生了根本性的变化，教师不再是简单的知识传授者，而是一个组织者和引导者，并调动了每一位学生的学习主动性，使他们真正成为学习的主人，积极地参与教学的每一个环节，努力地探索解决问题的方法，大胆地发表自己的观点。学生始终保持
43、着高昂的学习情绪，切身经历了“做数学”的全过程，感受了学习数学的快乐，品尝了成功的喜悦。 一、创设情境，激发兴趣 “爱美之心，人皆有之”，追求美、崇尚美是人之天性，儿童亦然。整堂课以欣赏美为线索展开教学，本课就创设了这样一个情景动画:“碧草青青花盛开,彩蝶双双久徘徊”，在优美的小提琴协奏曲的渲染中，两只小企鹅到北京旅游，介绍沿途参观的很多着名景物(这些景物都是对称的)，带领学生一起畅游了一番，学生在愉悦的气氛中开始观察优美的画面，仿佛身临其境，领略了对称物体之美，从学生熟知的生活情境出发，让学生初步感知对称的事物。这种赢造宽松愉悦、开放式的环境，学生纷纷自觉投入到学习活动中，观察这些实物的特点
44、它们的两边都是一模一样的，从而引入对称，逐步将实物抽象成平面图形，通过操作实践发现其共同特征，导入教学新授，达到串连教材的效果，让学生在这种欣赏美的教学情景中快乐的学习，激发学生学习数学的兴趣，开拓学生的思维，发展学生的联想、想象能力，引导学生感受美、鉴赏美、领悟美，达到情境(景)交融的教学效果。 (点评:以学生身边的事物为媒介，使教材内容从具体到抽象，从感性到理性，循序渐进地指导学生认识生活中轴对称性质的事物，使学生进一步深入地认识几何平面图形的本质特征。在这个过程中，教师注意到图片的颜色，在教具和课件制作中采用色彩鲜明的颜色，使学生感受到颜色的美，物体的美丽，教师创设了一个这样美的情境，激
45、发了学生的学习兴趣，使学生真切感受到数学的美，来源于生活，来源于身边，体验到在数学中美的教育。) 二、实践操作、激活思维 summer of masonry construction, brick requires sufficient moist. 8.6.2.6 you must take the following measures to concrete construction in summer high temperature impact on concrete a. hardening speed up, vibrating difficulties reduced blee
46、ding, fast drying, easy to crack (plastic), high early strength, fast early hydration heat, less cooling, temperature increases rapidly, due to temperature difference cracks. B. pouring daytime high temperatures, due to the high temperature effect of concrete strength, stability, in varying degrees,
47、 on mixing processes, perfusion vibration and moisture conservation, effective measures should be taken. 2) main measures taken by a. temperature control the water temperature in your standard mix proportion of concrete 2 degrees, the concrete temperature 0.5 degrees. B. with the controlled addition
48、 of retarder agent can reduce the effects of concrete under high temperature, but make some performance degradation of concrete, so when you are using additives must be implemented upon approval by the supervising engineer. C. time control suitable for work at night, should seek to reduce the mixing
49、 time and shipping time at high temperatures. D. strengthen the conservation and high temperatures after pouring in the early days of continuous water conservation to prevent surface drying and covering thin-film wet grass bag to make it moist State in 24 hours. 8.6.3 8.6.3.1 winter construction measures in winter construction preparation 1) required winter construction materials