六年级数学下册教案1

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1、to keep the city safe were gone in the thirty second the earth moved. Out at sea it was calm. No wind came up. Yet from every direction-east,weast,north,andsouth,strong winds blew upon the unlucky city. Man himself had to make ruins of the citys best buildings so that they would not be a danger to t

2、hose in the streets. A list of buildings undesteryed was now only a few addresses. A list of the brave men and the women would fill a library. A list of all those killed will never be made. Amazing as it may seem, Wednesday night was a quiet night. There were no crowds. The policemen saidnothing; ev

3、en their horses were quit. There were no shouts or people doing crazy things. In all those terrible hours I saw not one woman who cried, not one man who was excited. Before the fires, through the night, thousands and thousands of people who had lost their homes left for safety. Some were covered in

4、blankets. Sometimes whole families put everything they owned and could save into wagons. They helped one another climb the high hills around the city. Never in all SanFrsncios histroy were her people so kind as on that terrible night.Unit 5Elias storyMy name is Elias. I am a poor worker in SouthAfri

5、ca. The time when I first met Nelson Mandela was a very difficult period of my life. I was twelve years old. It was in 1952 and Mandela was the black lawyer to whom I went for advice. He offered guidance to poor black people on their legal problems. He was generous with his time, for which I was gra

6、teful.I needed his help because I had very little education. I began school at six. The school where I studied for only two years was three kilometers away. I had to leave because my family could not continue to pay the school fees and the bus fare. I could not read or write well. After trying hard,

7、 I got a job in a gold mine. However, this was a time when one had to got to have a passbook to live in Johannesburg. Sadly I did not have it because I was not born there, and I worried about whether I would become out of work.The day when Nelson Mandela helped me was one of my happiest. He told me

8、how to get the correct papers so I could stay in Johannesburg. I became more hopeful about my future. I never forgot how kind Mandela was. When he organized the ANC Youth League, I joined it as soon as I could. He said:“ The last thirty years have seen the greatest number of laws stopping our rights

9、 and progress,until today we have reached a stage where we have almost no rights at all.”It was the truth. Black people could not vote or choose their leaders. They could not get the jobs they wanted. The parts of town in which they had to live were decided by white people. The places outside the to

10、wns where they were sent to live were the poorest parts of South Africa. No one could grow food there,. In fact as Nelson Mandela said:“ We were put into a position in which we had either to accept we were less important, or fight the government. We chose to attack the laws. We first broke the law i

11、n a way which was peaceful; when this was not allowed only then did we decide to answer violence with violence.”As a matter of fact, I do not like violence but in 1963 I helped him blow up some government buildings. It was very dangerous because if I was caught I could be put in prison. But I was ve

12、ry happy to help because I knew it would help us achieve our dream of making black and white people equal.The rest of Elias storyYou cannot imagine how the name of Robben Island made us afraid. It was a prison from which no one escaped. There I spent the hardest time of my life. But when I got there

13、 Nelson Mandela was also there and he helped me. Mr Mandela began a school for those of us who had little learning. We read books under our blankets and used anything we could find to make candles to see the words. I became a good student. I wanted to study for degree but I was not allowed to do tha

14、t. Later, Mr Mandela allowed the prison guards to join us. He said they should not be stopped from studying for their degrees. They were not cleverer than me, but they did pass their exams. So I knew I could get a degree too. That made me feel good about myself.When I finished the four years in pris

15、on, I went to find a job. Since I was better educated, I got a job working in an office. However, the police found out and told my boss that I had been in prison for blowing up government buildings. So I lost my job. I did not work again for twenty years until Mr Mandela and the ANC came to power in

16、 1994. All that time my wife and children had to beg for food and help from relatives or friends. Luckily Mr Mandela remembered me and gave me a job taking tourists around my old prison on Robben Island. I felt bad the first time I talked to a group. All the terror and fear of that time came back to

17、 me. I remembered the beatings and the cruelty of the guards and my friends who had died. I felt I would not be able to do it, but my family encouraged me. They said that the job and the pay from the new South Africa government were my reward after working all my life for equal rights for the Blacks

18、. So now at 51 I am proud to show visitors over the prison, for I helped to make our people free in their own land.A follower of Bill GatesI have been a friend of Bill Gates for a long time. I knew him when he was a student at Harvard University. We were surprised when he left University to set up h

19、is own company” Microsoft” and make his own software. But he was the clever one! He is very good at writing computer languages and almost all computers now use Microsoft software. The program “Word” is used from Britain to China! Of course he has made a lot of money and that makes people very jealou

20、s. They want to stop his success. Even the government is against him and has tried to break his company into two parts. They say that he is unfair to other people who want to sell similar software. Because hefits his new software free in every new computer, the government says he is stopping other c

21、ompanies from selling their programs. This is not fair. Everyone should be able to do what they can to make their company bigger. Bill Gates has not only done what he can to stop other competitors. He is very rich, but he is generous. He has given millions of dollars to help the education and the he

22、alth of many children around the world. You could not meet a better man than Bill Gates.A competitors of Bill GatesBill Gates has been very successful and become very rich. He is very generous but how has he got his money? He has down this by making sure that no one else will be able to compete with

23、 his software. His software is not the best but it is used most widely in the world. When he sees what is needed, he makes a program and produces it quicker than anybody else. That way he gets a large part of the software market. Then he works on improving the software later. He tries hard to stop o

24、thers making better software. In 1995 the government tried to make things fairer for people like me. The government wanted to make Microsoft into two companies so that neither of them was so strong nor so rich. This meant that they could not stop somebody else making new software. I always wonder ho

25、w he could get so rich so quickly. Has he done it by fair means? Or has he done it by being a computer bully?必修二Unit 1In search of the amber roomFrederick William I, the king of Prussia, could never have imagined that his greatest gift to the Russian people would have such an amazing history. This g

26、ift was the Amber Room, which was given this name because several tons of amber were used to make it. The amber which was selected had a beautiful yellow-brown colour like honey. The design of the room was in the fancy style popular in those days. It was also a treasure decorated with gold and jewel

27、s, which took the countrys best artists about ten years to make.In fact, the room was not made to be a gift. It was designed for the palace of Fredrick I. However, the next King of Prussia, Fredrick William I, to whom the amber room belonged, decided not to keep it. In 1716 he gave it to Peter the G

28、reat. In return, the Czar sent him a troop of his best soldiers. So the Amber Room became part of the Czars winter palace in St Petersburg. About four metres long, the room served as a small reception hall for important vistors. Later, Catherine had the Amber Room moved to a palace outside St Peters

29、burg where she spent her summers. She told her artists to add more details to it. In 1770 the room was completed the way she wanted. Almost six hundred candles lit the room, and its mirrors and pictures shone like gold. Sadly, although the Amber Room was cnsidered one of the wonders of the world, it

30、 is now missing.In September 1941, the Nazi army was near St Petersburg. This was atime when the two countries were at war. Before the Nazis could get to the summer palace, the Russians were able to remove some furnitures and small art objects from the Amber Room. However, some of the Nazis secretly

31、 stole the room itself. In less than two days 100000 pieces were put inside twenty-seven wooden boxes. There is no doubt that the boxes were then put on a train for Konigsberg, which was at a time a German city on the Baltic Sea. After that, what happened to the Amber Room remains a mystery.Recently

32、, the Russians and Germans have built a new Amber Room at the summer palace. By studying old photos of the former Amber room, they have made the new one looke like the old one. In 2003 it was ready for the people of St Petersburg when they celebrated the 300th bithday of their city.A fact of an opin

33、ionWhat is a第一单元 负数第一课时认识负数教学目标:1使学生在现实情境中初步认识负数,了解负数的作用,感受运用负数的需要和方便。2使学生知道正数和负数的读法和写法,知道0既不是正数,又不是负数。正数都大于0,负数都小于0。3使学生体验数学和生活的密切联系,激发学生学习数学的兴趣,培养学生应用数学的能力。教学重点:初步认识正数和负数以及读法和写法。教学难点:理解0既不是正数,也不是负数。教学具准备:温度计、练习纸、卡片等。教学过程:一、 安全教育同学们,要注意野外用火,防止火灾发生。二、 游戏导入(感受生活中的相反现象)1、游戏:我们来玩个游戏轻松一下,游戏叫做我反 我反 我反反反。

34、游戏规则:老师说一句话,请你说出与它相反意思的话。向上看(向下看)向前走200米(向后走200米)电梯上升15层(下降15层)。2、下面我们来难度大些的,看谁反应最快。我在银行存入了500元(取出了500元)。五(1)班得了20分(扣了20分)。10月份,学校小卖部赚了500元。(亏了500元)。零上10摄式度(零下10摄式度)。三、教学例11、认识温度计,理解用正负数来表示零上和零下的温度。出示地图:点击南京出示温度计和南京的图片。首先来看一下南京的气温。这里有个温度计。我们先来认识温度计,请大家仔细观察:这样的一小格表示多少摄式度呢?5小格呢?10小格呢?B、现在你能看出南京是多少摄式度吗

35、? (是0。)你是怎么知道的?(那里有个0,表示0摄式度)。(2)上海的气温:上海的最低气温是多少摄式度呢?(在温度计上拨一拨)拨的时候是怎样想的呢?(在零刻度线以上四格)指出:上海的气温比0要高,是零上4摄式度。(教师结合课件,突出上海的气温在零刻度线以上)。(3)了解首都北京的最低气温:北京又是多少摄式度呢?与南京的0比起来,又怎样了呢?(比南京的0要低)你能用一个手势来表示它和0的关系吗?(对,北京的气温比0度低,是零下4摄式度)你能在温度计上拨出来吗?(4)比较:现在我们已经知道了这三个地方的最低气温。仔细观察上海和北京的最低气温,它们一样吗?(不一样,一个在0以上,一个在0以下)。上

36、海的气温比0高,是零上4摄式度,我们可以记作+4,读作正四摄式度,写的时候先写一个正号(指出是正号不是加号,意义和读法都不同了)再写一个4(板书),大家跟我一起来比划一下。+4也可以直接写成4,把正号省略了。所以同学们所说的4也就是+4。(板书)北京的气温比0低,是零下4摄式度。我们可以用-4来表示零下4摄式度(板书-4)。跟老师一起来读一下。写的时候可以先写一个负号(指出是负号不是减号)再写一个4就可以了,同桌互相比划一下。(5)小结:通过刚才对三个城市的温度的了解,我们知道记录温度时,以0为界线,用象+4或4这些数可以来表示零上温度,用-4这样的数可以表示零下温度。2、小结:通过刚才的学习

37、,我们得出:以零摄式度为界线,零上温度用正几或直接用几来表示,零下温度用负几来表示。四、学习珠峰、吐鲁番盆地的海拔表达方法(P4第2题)珠穆朗玛峰比海平面高,吐鲁番盆地比海平面低。大家再想想:你能用一种简单的方法来记录一下这两个地方的海拔吗? (1)交流:珠穆朗玛峰的海拔可以记作:+8844.43米或8844.43米。吐鲁番盆地的海拔可以记作:-155米。(板书)(2)小结:以海平面为界线,+8844.43米或8844.43米这样的数可以表示海平面以上的高度,-155米这样的数可以表示海平面以下的高度。五、小组讨论,归纳正数和负数。1、通过刚才的学习,我们收集到了一些数据(课件显示)我们可以用

38、这些数来表示零上温度和零下温度,还可以表示海平面以上的高度和海平面以下的高度。那么你们观察一下这些数,它们一样吗?你们想帮它们分分类吗?2、学生交流、讨论。3、指出:因为+8844.43也可以写成8844.43米,所以有正号和没正号都可以归于一类。提出疑问:0到底归于哪一类?(引导学生争论,各自发表意见) 如果都同意分三类的,老师可以出难题:我觉得0可以分在4它们一类啊,你们怎么来说服我? 如果有学生发表分三类的,有的分两类的,可以引导他们互相争论。六、巩固练习家作:P1-P2页第二课时比较正数和负数的大小教学目的:1、借助数轴初步学会比较正数、0和负数之间的大小。2、初步体会数轴上数的顺序,

39、完成对数的结构的初步构建。教学重、难点:负数与负数的比较。教学过程:一、 安全教育同学们,要注意用火安全,防止火灾发生;注意天气变化,防止感冒。二、 复习1、读数,指出哪些是正数,哪些是负数?-8 5.6 +0.9 - + 0 -822、如果+20%表示增加20%,那么-6%表示 。3、某日傍晚,黄山的气温由上午的零上2摄氏度下降了7摄氏度,这天傍晚黄山的气温是 摄氏度。三、新授:(一)教学例3:1、怎样在数轴上表示数?(1、2、3、4、5、6、7)2、出示例3:(1)提问你能在一条直线上表示他们运动后的情况吗?(2)让学生确定好起点(原点)、方向和单位长度。学生画完交流。(3)教师在黑板上话

40、好直线,在相应的点上用小图片代表大树和学生,在问怎样用数表示这些学生和大树的相对位置关系?(让学生把直线上的点和正负数对应起来。(4)学生回答,教师在相应点的下方标出对应的数,再让学生说说直线上其他几个点代表的数,让学生对数轴上的点表示的正负数形成相对完整的认识。(5)总结:我们可以像这样在直线上表示出正数、0和负数,像这样的直线我们叫数轴。(6)引导学生观察:A、从0起往右依次是?从0起往左依次是?你发现什么规律?B、在数轴上分别找到1.5和-1.5对应的点。如果从起点分别到.5和-1.5处,应如何运动?(7)练习:做一做的第1、2题。(二)教学例4:1、出示未来一周的天气情况,让学生把未来

41、一周每天的最低气温在数轴上表示出来,并比较他们的大小。2、学生交流比较的方法。3、通过小精灵的话,引出利用数轴比较数的大小规定:在数轴上,从左到右的顺序就是数从小到大的顺序。4、再让学生进行比较,利用学生的具体比较来说明“-8在-6的左边,所以-8-6”5、再通过让另一学生比较“86,但是-8-6”,使学生初步体会两负数比较大小时,绝对值大的负数反而小。6、总结:负数比0小,正数比0大,负数比正数小。7、练习:做一做第3题。四、巩固练习1、练习一第4、5题。 2、练习一第6题。3、实践题记录小组同学的身高和体重,以平均身高体重为标准记为0m或(0kg)。超过的记为正数,不足的记为负数,然后按从

42、大到小的顺序排列。五、全课总结(1)在数轴上,从左到右的顺序就是数从小到大的顺序。(2)负数比0小,正数比0大,负数比正数小。六、作业1、 课外作业:练习一的1、4、5、6题2、 家作:P3-P4页教学反思:第二单元 圆柱与圆锥 单元目标:1、使学生认识圆柱和圆锥,掌握它们的特征;认识圆柱的底面、侧面和高;认识圆锥的底面和高。2、 使学生理解求圆柱的侧面积和表面积的计算方法,并会正确计算。3、 使学生理解求圆柱、圆锥体积的计算公式,会运用公式计算体积、容积,解决有关的简单实际问题。单元重点: 掌握圆柱的表面积的计算方法和圆柱、圆锥体积的计算公式。单元难点: 圆柱、圆锥体积的计算公式的推导1、圆

43、柱第一课时圆柱的认识教学内容:教科书第1012页圆柱的认识,练习二的第14题教学目标:1、借助日常生活中的圆柱体,认识圆柱的特征和圆柱各部分的名称,能看懂圆柱的平面图;认识圆柱侧面的展开图。2、培养学生细致的观察能力和一定的空间想像能力。3、激发学生学习的兴趣。教学重点:认识圆柱的特征。教学难点:看懂圆柱的平面图。教学过程:一、 安全教育同学们,要注意用火安全,防止火灾发生;教育学生在平时的学习、生活中要养成良好的卫生习惯。二、 复习1、已知圆的半径或直径,怎样计算圆的周长?(指名学生回答,使学生熟悉圆的周长公式:C2r或Cd)2、求下面各圆的周长(教师依次出示题目,然后指名学生回答,其他学生

44、评判答案是否正确)(1)半径是1米(2)直径是3厘米(3)半径是2分米(4)直径是5分米二、认识圆柱特征1、整体感知圆柱(1)谈谈圆柱你喜欢圆柱吗?请同学说说喜欢圆柱的理由。(美观、实用、安全、可滚动)(2)找找圆柱,请同学找出生活中圆柱形的物体。2、圆柱的表面(1)摸摸圆柱。请同学摸摸自己手中圆柱的表面,说说发现了什么?(2)指导看书:摸到的上下两个面叫什么?它们的形状大小如何?摸到的圆柱周围的曲面叫什么?(上下两个面叫做底面,它们是完全相同的两个圆。圆柱的曲面叫侧面。)3、圆柱的高(1)图片显示:一根竖放的大针管中的药水由高到低的变化过程,引导学生思考:药水水柱的高低和水柱的什么有关?(2

45、)引导小结:水柱的高低和水柱的高有关(3)结合课本回答什么叫圆柱的高。(板书:圆柱两个底面之间的距离叫做高。)(4)讨论交流:圆柱的高的特点。课件显示:装满牙签的塑料盒,问:这些牙签是圆柱的高吗?假如牙签细一些,再细一些,能装多少根?初步感知:面对圆柱的高,你想说些什么?归纳小结并板书:圆柱的高有无数条,高的长度都相等。深化感知:面对这数不清的高,测量哪一条最为简便?老师引导学生操作分析,得出测量圆柱边上的这条高最为简便,同时课件上的圆柱体闪烁边上的一条高4圆柱的侧面展开(例2)(1)动手操作:请同学分小组拿出橡皮、蜡笔、水彩笔、固体胶水等有商标纸的圆柱形实物,分别把商标纸剪开,再打开,观察商

46、标纸的形状反馈后讨论:展开后得到长方形和正方形的是怎样剪的?展开后得到平行四边形的是怎样剪的? 长方形板书:沿高剪斜着剪:平行四边形 正方形强调:我们先研究具有代表性的长方形与圆柱的关系(2)寻求发现展开的长方形的长和宽与圆柱的关系师生一起把展开的长方形还原成圆柱的侧面,再展开,在重复操作中观察。学生再观察电脑演示上述过程(用彩色线条突出圆柱底面周长和高转化成长方形长和宽的过程。)同学交流后说出自己的发现:这个长方形的长就是圆柱底面的周长,宽就是圆柱的高。(3)延伸发现展开的平行四边形的底和高及正方形的边长与圆柱的关系。讨论:平行四边形能否通过什么方法转化成长方形?课件显示:平行四边形通过割补

47、转变成长方形,再还原成圆柱侧面的动画过程。想一想:当圆柱底面周长与高相等时,侧面展开图是什么形?引导小结:不管侧面怎样剪,得到各种图形,都能通过割补的方法转化成长方形其中正方形是特殊的长方形三、巩固练习1.做第11页“做一做”的第2题。2.做第15页练习二的第3题。教师行间巡视,对有困难的学生及时辅导。3.做第15页练习二的第4题。四、作业家作:P5页 板书:长方形沿高剪斜着剪:平行四边形 正方形圆柱的底面周长 长方形的长圆柱的高 长方形的宽第二课时圆柱的表面积教学内容:P1314页例3例4,完成“做一做”及练习二的部分习题。教学目标:1、 在初步认识圆柱的基础上理解圆柱的侧面积和表面积的含义

48、,掌握圆柱侧面积和表面积的计算方法,会正确计算圆柱的侧面积和表面积,能解决一些有关实际生活的问题。2、 培养学生良好的空间观念和解决简单的实际问题的能力。3、 通过实践操作,在学生理解圆柱侧面积和表面的含义的同时,培养学生的理解能力和探索意识。教学重点:掌握圆柱侧面积和表面积的计算方法。教学难点:运用所学的知识解决简单的实际问题。教学过程:一、 安全教育同学们,要注意用火安全,防止火灾发生;教育学生在学校应学会保护自己的人身安全、防止意外发生。二、 复习1、指名学生说出圆柱的特征2、口头回答下面问题(1)一个圆形花池,直径是5米,周长是多少?(2)长方形的面积怎样计算?板书:长方形的面积长宽三

49、、新课1、圆柱的侧面积。(1)圆柱的侧面积,顾名思义,也就是圆柱侧面的面积。(2)出示圆柱的展开图:这个展开后的长方形的面积和圆柱的侧面积有什么关系呢?(学生观察很容易看到这个长方形的面积等于圆柱的侧面积)(3)那么,圆柱的侧面积应该怎样计算呢?(引导学生根据展开后的长方形的长和宽与圆柱底面周长和高的关系,可以知道:圆柱的侧面积底面周长高)2、侧面积练习:练习七第5题(1)学生审题,回答下面的问题:这两道题分别已知什么,求什么?计算结果要注意什么?(2)指定一名学生板演,其他学生在练习本上做教师行间巡视,注意发现学生计算中的错误,并及时纠正。(3)小结:要计算圆柱的侧面积,必须知道圆柱底面周长

50、和高这两个条件,有时题里只给出直径或半径,底面周长这个条件可以通过计算得到,在解题前要注意看清题意再列式。3、理解圆柱表面积的含义(1)让学生把自己制作的圆柱模型展开,观察一下,圆柱的表面由哪几个部分组成? (2)圆柱的表面积是指圆柱表面的面积,也就是圆柱的侧面积加上两个底面的面积。公式:圆柱的表面积圆柱的侧面积底面积24、教学例4(1)出示例3。学生读题,明确已知条件(2)求的是厨师帽所用的材料,需要注意些什么?(厨师帽没有下底面,说明它只有一个底面)(3)指定两名学生板演,其他学生独立进行计算教师行间巡视,注意察看最后的得数是否计算正确。(由此指出:这道题使用的材料要比计算得到的结果多一些

51、。因此,这里不能用四舍五入法取近似值。这道题要保留整百平方厘米,省略的十位上即使是4或比4小,都要向前一位进1。这种取近值的方法叫做进一法。) 侧面积:3.1420281758.4(平方厘米) 底面积:3.14(202)2314(平方厘米) 表面积:1758.43142072.42080(平方厘米)5、小结:在实际应用中计算圆柱形物体的表面积,要根据实际情况计算各部分的面积如计算烟筒用铁皮只求一个侧面积;水桶用铁皮是侧面积加上一个底面积;油桶用铁皮是侧面积加上两个底面积,求用料多少,一般采用进一法取值,以保证原材料够用四、巩固练习1做第14页“做一做”。(求表面积包括哪些部分?)2. 练习七第

52、6题。五、作业:家作P6页板书: 圆柱的侧面积底面周长高圆柱的表面积圆柱的侧面积底面积2例4:侧面积:3.1420281758.4(平方厘米) 底面积:3.14(202)2314(平方厘米) 表面积:1758.43142072.42080(平方厘米)第三课时圆柱的表面积练习课教学内容:练习二余下的练习。教学目标:1、会正确计算圆柱的侧面积和表面积,能解决一些有关实际生活的问题。2、培养学生良好的空间观念和解决简单的实际问题的能力。教学重点:运用所学的知识解决简单的实际问题。教学难点:运用所学的知识解决简单的实际问题。教学过程:一、 安全教育同学们,要注意用火安全,防止火灾发生;同学们在无论在校

53、内校外都要注意饮食习惯和卫生二、 复习1、圆柱的侧面积怎么求?(圆柱的侧面积底面周长高)2、圆柱的表面积怎么求?(圆柱的表面积圆柱的侧面积底面积2)3、练习二第14题:根据已知条件求出圆柱的侧面积和表面积。(第题已知圆柱的底面周长,对于求侧面积较有利。但在求底面积时,要先应用C2来求出圆柱的底面半径)二、实际应用1、练习二第13题(1)复习长方体、正方体的表面积公式:长方体的表面积(长宽长高宽高)2正方体的表面积棱长棱长6(2)学生独立完成第13题:计算长方体、正方体、圆柱体的表面积,并指名板演。2、练习二第7题(1)用教具辅助,引导学生思考:前轮转动一周,压路面的面积是指什么?(通过圆柱教具

54、的直观演示,使学生看到所压路面的面积就是前轮的侧面积)(2)学生独立完成这道题,集体订正。3、练习二第9题(1)学生通过读题理解题意,思考“抹水泥的部分”是指哪几个面?(侧面和下底面,也就是只有一个底面积)(2)指名板演,其他学生独立完成于课堂练习本上。4、练习二第16题(1)学生读题理解题意后尝试独立解题。(2)集体评讲,让学生理解计算“制作中间的轴需要多大的硬纸板”,就是计算硬纸轴的侧面积,卫生纸的宽度就是硬纸板的高度。5、练习二第19题(1)学生小组讨论:可以漆色的面有哪些?(2)通过教具演示,使学生明白圆柱及长方体表面被遮住的部分刚好是圆柱的三个底面积。因此,计算油漆的面积就是计算长方

55、体表面积与圆柱侧面积之和减去圆柱的一个底面积。(3)提醒学生将计算结果化成以平方米为单位的数,并可根据实际情况保留近似数。三、作业1、 练习二第7、9、13、16-20题。2、 家作:家作P7页板书: 圆柱的侧面积底面周长高 圆柱的表面积圆柱的侧面积底面积2 长方体的表面积(长宽长高宽高)2正方体的表面积棱长棱长6教学反思:第四课时圆柱的体积教学内容:P1920页例5、6及补充例题,完成“做一做”及练习三1-4题。教学目标:1、通过用切割拼合的方法借助长方体的体积公式推导出圆柱的体积公式,能够运用公式正确地计算圆柱的体积和容积。2、初步学会用转化的数学思想和方法,解决实际问题的能力3、渗透转化

56、思想,培养学生的自主探索意识。教学重点:掌握圆柱体积的计算公式。教学难点:圆柱体积的计算公式的推导。教学过程:一、 安全教育同学们,要注意用火安全,防止火灾发生;同学们在校时,需要认真学习小学生守则和小学生日常行为规范,并认真遵守和执行。二、 复习1、长方体的体积公式是什么?(长方体的体积长宽高,长方体和正方体体积的统一公式“底面积高”,即长方体的体积底面积高)2、拿出一个圆柱形物体,指名学生指出圆柱的底面、高、侧面、表面各是什么,怎么求。3、复习圆面积计算公式的推导过程:把圆等分切割,拼成一个近似的长方形,找出圆和所拼成的长方形之间的关系,再利用求长方形面积的计算公式导出求圆面积的计算公式。

57、二、新课1、圆柱体积计算公式的推导。(1)用将圆转化成长方形来求出圆的面积的方法来推导圆柱的体积。(沿着圆柱底面的扇形和圆柱的高把圆柱切开,可以得到大小相等的16块,把它们拼成一个近似长方体的立体图形课件演示)(2)由于我们分的不够细,所以看起来还不太像长方体;如果分成的扇形越多,拼成的立体图形就越接近于长方体了。(课件演示将圆柱细分,拼成一个长方体)(3)通过观察,使学生明确:长方体的底面积等于圆柱的底面积,长方体的高就是圆柱的高。(长方体的体积底面积高,所以圆柱的体积底面积高,VSh)2、教学补充例题(1)出示补充例题:一根圆柱形钢材,底面积是50平方厘米,高是2.1米。它的体积是多少?(

58、2)指名学生分别回答下面的问题: 这道题已知什么?求什么? 能不能根据公式直接计算? 计算之前要注意什么?(计算时既要分析已知条件和问题,还要注意要先统一计量单位)(3)出示下面几种解答方案,让学生判断哪个是正确的VSh=502.1105(立方厘米)答:它的体积是105立方厘米。2.1米210厘米VSh=5021010500(立方厘米)答:它的体积是10500立方厘米。50平方厘米0.5平方米VSh=0.52.11.05(立方米)答:它的体积是1.05立方米。50平方厘米0.005平方米VSh=0.0052.10.0105(立方米)答:它的体积是0.0105立方米。先让学生思考,然后指名学生回

59、答哪个是正确的解答,并比较一下哪一种解答更简单对不正确的第、种解答要说说错在什么地方(4)做第20页的“做一做”。学生独立做在练习本上,做完后集体订正3、引导思考:如果已知圆柱底面半径r和高h,圆柱体积的计算公式是怎样的?(Vr2h)4、教学例6(1)出示例5,并让学生思考:要知道杯子能不能装下这袋牛奶,得先知道什么?(应先知道杯子的容积)(2)学生尝试完成例6。 杯子的底面积:3.14(82)23.14423.141650.24(cm2) 杯子的容积:50.2410502.4(cm3)502.4(ml)5、比较一下补充例题、例6有哪些相同的地方和不同的地方?(相同的是都要用圆柱的体积计算公式

60、进行计算;不同的是补充例题已给出底面积,可直接应用公式计算;例6只知道底面直径,要先求底面积,再求体积)三、巩固练习1、做第21页练习三的第1题2、练习三的第2题这两道题分别是已知底面半径(或直径)和高,求圆柱体积的习题要求学生审题后,知道要先求出底面积,再求圆柱的体积。板书: 圆柱的体积底面积高 VSh或Vr2h例6: 杯子的底面积:3.14(82)23.14423.141650.24(cm2) 杯子的容积:50.2410502.4(cm3)502.4(ml) 第五课时圆柱的体积练习课 教学目标:1、使学生能够运用公式正确地计算圆柱的体积和容积。2、初步学会用转化的数学思想和方法,解决实际问

61、题的能力3、渗透转化思想,培养学生的自主探索意识。教学重点:掌握圆柱体积的计算公式。教学难点:灵活应用圆柱的体积公式解决实际问题。教学过程:一、 复习1、复习圆柱体积的推导过程长方体的底面积等于圆柱的底面积,长方体的高就是圆柱的高。长方体的体积底面积高,所以圆柱的体积底面积高,即VSh。2、复习长方体的体积公式后,让学生独立完成练习三第6题,并指名板演。二、解决实际问题1、练习三第7题。学生思考:要求粮囤所能装的玉米的重量,需先知道什么?然后独立完成。2、练习三第5题。(1)指导学生变换公式:因为VSh,所以hVS。也可以列方程解答。(2)学生选择喜爱的方法解答这道题目。3、练习三第8题。(1

62、)学生读题后,指名说说对题意的理解:求减少的土方石就是求月亮门所占的空间,而月亮门所占的空间是一个底面直径为2米,高为0.25米的圆柱。(2)在充分理解题意后学生独立完成,集体订正。4、练习三第9、10题(1)学生独立审题,完成9、10两题。(2)评讲第9题:要怎样才能判断出800ml的果汁够倒三杯吗?必须先求出什么?怎么求?(需先求出圆柱形玻璃杯的容积,用公式VSh)(3)指名说说解答第10题的思路:根据两个圆柱的底面积相等这一条件,先求出其中一个圆柱的底面积。利用这个底面积再求出另一个圆柱的体积。三、布置作业1、 练习三4、5、7、8、10题。2、 家作P8- P9页教学反思:2、圆锥第六课时圆锥的认识教学内容:教科书P2326的内容,P24“做一做”,完成练习四的1、2题。教学目标:1、 认识圆锥,圆锥的高和侧面,掌握圆锥的特征,会看圆锥的平面图,会正确测量圆锥的高,能根据实验材料正确制作圆锥。2、 通过动手制作圆锥和测量圆锥的高,培养学生的动手操作能力和一定的空间想象能力。3、 培养学生的自主探索意识,激发学生强烈的求知欲望。教学重点:掌握圆锥的特征。教学难点:正确理解圆锥的组成。教学

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