Step 7: complete the discourse according to the grammar rules.Cholera used to be one of the most 1.__________ (fear) diseases in the world. In the early 19th century, _2_________ an outbreak of cholera hit Europe, millions of people died. But neither its cause, 3__________ its cure was understood. A British doctor, John Snow, wanted to solve the problem and he knew that cholera would not be controlled _4_________ its cause was found. In general, there were two contradictory theories 5 __________ explained how cholera spread. The first suggested that bad air caused the disease. The second was that cholera was caused by an _6_________(infect) from germs in food or water. John Snow thought that the second theory was correct but he needed proof. So when another outbreak of cholera hit London in 1854, he began to investigate. Later, with all the evidence he _7_________ (gather), John Snow was able to announce that the pump water carried cholera germs. Therefore, he had the handle of the pump _8_________ (remove) so that it couldn't be used. Through his intervention,the disease was stopped in its tracks. What is more, John Snow found that some companies sold water from the River Thames that __9__________________ (pollute) by raw waste. The people who drank this water were much more likely _10_________ (get) cholera than those who drank pure or boiled water. Through John Snow's efforts, the _11_________ (threaten) of cholera around the world saw a substantial increase. Keys: 1.feared 2.when 3. nor 4.unless 5.that/which 6.infection 7.had gathered 8.removed 9.was polluted 10.to get 11. threat
Step 5: After learning the text, discuss with your peers about the following questions:1.John Snow believed Idea 2 was right. How did he finally prove it?2. Do you think John Snow would have solved this problem without the map?3. Cholera is a 19th century disease. What disease do you think is similar to cholera today?SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.keys:1. John Snow finally proved his idea because he found an outbreak that was clearly related to cholera, collected information and was able to tie cases outside the area to the polluted water.2. No. The map helped John Snow organize his ideas. He was able to identify those households that had had many deaths and check their water-drinking habits. He identified those houses that had had no deaths and surveyed their drinking habits. The evidence clearly pointed to the polluted water being the cause.3. SARS and Covid-19 because they are both deadly and fatally infectious, have an unknown cause and need serious public health care to solve them urgently.Step 6: Consolidate what you have learned by filling in the blanks:John Snow was a well-known _1___ in London in the _2__ century. He wanted to find the _3_____ of cholera in order to help people ___4_____ it. In 1854 when a cholera __5__ London, he began to gather information. He ___6__ on a map ___7___ all the dead people had lived and he found that many people who had ___8____ (drink) the dirty water from the __9____ died. So he decided that the polluted water ___10____ cholera. He suggested that the ___11__ of all water supplies should be _12______ and new methods of dealing with ____13___ water be found. Finally, “King Cholera” was __14_____.Keys: 1. doctor 2. 19th 3.cause 4.infected with 5.hit 6.marked 7.where 8.drunk 9.pump 10.carried 11.source 12.examined 13.polluted 14.defeatedHomework: Retell the text after class and preview its language points
This happens because the dish soap molecules have a strong negative charge, and the milk molecules have a strong positive charge. Like magnets, these molecules are attracted to each other, and so they appear to move around on the plate, taking the food coloring with them, making it look like the colors are quickly moving to escape from the soap.Listening text:? Judy: Oh, I'm so sorry that you were ill and couldn't come with us on our field trip. How are you feeling now? Better?? Bill: Much better, thanks. But how was it?? Judy: Wonderful! I especially liked an area of the museum called Light Games.it was really cool. They had a hall of mirrors where I could see myself reflected thousands of times!? Bill: A hall of mirrors can be a lot of fun. What else did they have?? Judy: Well, they had an experiment where we looked at a blue screen for a while, and then suddenly we could see tiny bright lights moving around on it. You'll never guess what those bright lights were!? Bill: Come on, tell me!? Judy: They were our own blood cells. For some reason, our eyes play tricks on us when we look at a blue screen, and we can see our own blood cells moving around like little lights! But there was another thing I liked better. I stood in front of a white light, and it cast different shadows of me in every color of the rainbow!? Bill: Oh, I wish I had been there. Tell me more!? Judy: Well, they had another area for sound. They had a giant piano keyboard that you could use your feet to play. But then, instead of playing the sounds of a piano, it played the voices of classical singers! Then they had a giant dish, and when you spoke into it, it reflected the sound back and made it louder. You could use it to speak in a whisper to someone 17 meters away.? Bill: It all sounds so cool. I wish I could have gone with you? Judy: I know, but we can go together this weekend. I'd love to go there again!? Bill: That sounds like a great idea!
The newspaper reported more than 100 people had been killed in the thunderstorm.报纸报道说有一百多人在暴风雨中丧生。(2)before、when、by the time、until、after、once等引导的时间状语从句的谓语是一般过去时,以及by、before后面接过去的时间时,主句动作发生在从句的动作或过去的时间之前且表示被动时,要用过去完成时的被动语态。By the time my brother was 10, he had been sent to Italy.我弟弟10岁前就已经被送到意大利了。Tons of rice had been produced by the end of last month. 到上月底已生产了好几吨大米。(3) It was the first/second/last ... time that ...句中that引导的定语从句中,主语与谓语构成被动关系时,要用过去完成时的被动语态。It was the first time that I had seen the night fact to face in one and a half years. 这是我一年半以来第一次亲眼目睹夜晚的景色。(4)在虚拟语气中,条件句表示与过去事实相反,且主语与谓语构成被动关系时,要用过去完成时的被动语态。If I had been instructed by him earlier, I would have finished the task.如果我早一点得到他的指示,我早就完成这项任务了。If I had hurried, I wouldn't have missed the train.如果我快点的话,我就不会误了火车。If you had been at the party, you would have met him. 如果你去了晚会,你就会见到他的。
The discourse explores the link between food and culture from a foreign’s perspective and it records some authentic Chinese food and illustrates the cultural meaning, gerography features and historic tradition that the food reflects. It is aimed to lead students to understand and think about the connection between food and culture. While teaching, the teacher should instruct students to find out the writing order and the writer’s experieces and feelings towards Chinese food and culture.1.Guide the students to read the text, sort out the information and dig out the topic.2.Understand the cultural connotation, regional characteristics and historical tradition of Chinese cuisine3.Understand and explore the relationship between food and people's personality4.Guide the students to use the cohesive words in the text5.Lead students to accurately grasp the real meaning of the information and improve the overall understanding ability by understanding the implied meaning behind the text.1. Enable the Ss to understand the structure and the writing style of the passage well.2. Lead the Ss to understand and think further about the connection between food and geography and local character traits.Step1: Prediction before reading. Before you read, look at the title, and the picture. What do you think this article is about?keys:It is about various culture and cuisine about a place or some countries.
You have no excuse for not going.你没有理由不去。He was punished for not having finished his homework.他因未完成作业而受到惩罚。2.动词ing形式复合结构由物主代词或人称代词宾格、名词所有格或普通格加动词ing,即“sb./sb.'s+doing”构成。动词ing形式的复合结构实际上是给动词ing形式加了一个逻辑主语。动词ing形式的复合结构有四种形式:①形容词性物主代词+动词ing②名词所有格+动词ing③代词宾格+动词ing④名词+动词ingHer coming to help encouraged all of us.她来帮忙鼓舞了我们所有人。The baby was made awake by the door suddenly shutting.这个婴儿被突然的关门声吵醒了。Can you imagine him/Jack cooking at home?你能想象他/杰克在家做饭的样子吗?无生命名词无论是作主语还是作宾语都不能用第②种形式。Tom's winning first prize last year impressed me a lot.汤姆去年得了一等奖使我印象深刻。Do you mind my/me/Jack's/Jack leaving now?你介意我/杰克现在离开吗?Excuse me for my not coming on time.很抱歉我没能按时来。His father's being ill made him worried.他父亲病了,他很担心。We are looking forward to the singer's/the singer to give us a concert.我们盼望着这位歌手来给我们举办一场演唱会。
【教学设计】一、教学目的:1、引导学生关注生活,向生活学习语言。2、了解新词新语,能正确评价和运用新词新语。二、教学重难点:1、重点:认识并评价新词新语。2、难点:如何评价新词新语三、教学用时:一课时四、教学过程预设(一)导入新课以前如果有人说我可爱,我会很高兴:我还是有优点的哦。现在如果有人说我可爱,我就会心里嘀咕了:这是什么意思呀?同学们知道这有什么意思吗?(可爱=可怜没人爱)如果大家留心就会发现,类似这样的词语很多,在网上是特别流行,很新颖、独特,谁来列举几个?(点评学生所列举出的词语)网络上有新词新语,其它媒体(如报刊、电视等)都有新词新语。关于新词新语的概念,一般认为,新近创造出来的词语,或是旧词新用,这样的词语就叫新词新语。
二、互动交流,理解算法1.出示教科书第22页的情境图,提问:他们在干什么?你获得了什么信息?能提出什么问题?怎样列式?2.师:今天我们就学习一位数除三位数的计算方法。(板书课题:一位数除三位数)3.师:怎样计算238÷6呢?你能用估算的方法估计出大致结果吗?4.学生尝试独立完成例3的竖式计算。师:在这道题中被除数最高位上是2个百,2个百除以6,商不够1个百怎么办?师:谁能说一说商3个十的3写在商的什么位置上?为什么?教师边板演边说明:用除数6去乘3个十,积是18个十,表示被除数中已经分掉的数,写在23的下面。23减18得5,表示十位上还剩5个十。师:接下来该怎么办?(把被除数个位上的8落下来,与十位上的5合起来继续除。)师:最后结果是多少?5.启发学生想一想:如果一本相册有24页,一本相册能插得下这些照片吗?2本呢?
思考:洗衣机脱水时转速高时容易甩干衣物,还是转速低时容易甩干衣物?(2) 制作棉花糖的原理内筒与洗衣机的脱水筒相似,里面加入白砂糖,加热使糖熔化成糖汁。内筒高速旋转,黏稠的糖汁就做离心运动,从内筒壁的小孔飞散出去,成为丝状到达温度较低的外筒,并迅速冷却凝固,变得纤细雪白,像一团团棉花。5.离心现象的防止在水平公路上行驶的汽车,转弯时所需的向心力是由车轮与路面的静摩擦力提供的。如果转弯时速度过大,所需向心力F大于最大静摩擦力Fmax,汽车将做离心运动而造成交通事故。因此,在公路弯道处,车辆行驶不允许超过规定的速度。当高速转动的砂轮或者飞轮内部分子间相互作用力不足以提供所需向心力时,离心运动就会使他们破裂,甚至酿成事故。
【参考】“沧海月明珠有泪,蓝田日暖玉生烟。”沧海中的珍珠只有在明月之夜,才能流下晶莹的泪花;蓝田下的美玉只有在日暖之时,才能升腾飘逸的烟霞。物犹如此,人当如是。“沧海月明”与“蓝田日暖”优美意境的创设,不仅仅是诗人精妙绝伦艺术素养的表现和挥洒,更是诗人回答人生价值的标准和尺度。诗人以物推人,拓展深化了诗作的主题,整篇的闪光点在此,魂亦在此。【参考】“此情可待成追忆,只是当时已惘然。”追忆过去,尽管自己以一颗浸满血泪的真诚之心,付出巨大的努力,去追求美好的人生理想,可“五十弦”如玉的岁月、如珠的年华,值得珍惜之时却等闲而过;面对现实:恋人生离、爱妻死别、盛年已逝、抱负难展、功业未建……,幡醒悟之日已风光不再。如泣如诉的悲剧式结问,又让诗人重新回到对“人生价值到底是什么?到底该怎样实现?”深深的思考和迷惑之中,大大增强了诗作的震撼力。
(幻灯六)巴金作品《家》描写的是“五四”之后,成都地区一个封建大家庭走向崩溃的故事。故事集中在1920年冬到1921年秋的八九个月时间里。成都的一个官僚地主家庭高公馆,一家之主的高老太爷,封建专制,顽固不化。长房长孙觉新,为人厚道,却很软弱,原与梅表姐相爱,后屈从于老太爷之命而与李瑞珏结婚。后来梅和瑞珏双双惨死。觉新的胞弟觉民、觉慧积极参加爱国运动,从而和冯公馆的冯乐山成了死对头。觉民爱上琴,冯乐山却要他娶自己的侄孙女,在觉民觉慧的反抗下,他们终于取得胜利。觉慧爱上聪明伶俐的婢女鸣凤,但冯乐山却指名要娶鸣凤为妾,鸣凤坚决不从,投湖自尽…至此,觉新有所觉醒,而觉慧则毅然脱离家庭,投身革命。(故事主要以高家三兄弟的爱情遭际为线索。)
2、黛玉进入贾府到贾母处,她看到了什么?提示:从荣府西角门进去,走“一射之地”,转至垂花门,过穿堂,绕插屏,再经三间过厅,后面方是贾母居住的正房大院。“正面五间上房,皆雕梁画栋,两边穿山游廊厢房,挂着各色鹦鹉、画眉等鸟雀。”这样穿堂过厅一路行来,仆役、婆子、丫环轮番更换,的确给人以侯门深似海的感觉。然而贾母居处还不是正内室。3、黛玉去拜见二舅舅时又看到什么?提示:往东。“穿过一个东西的穿堂,向南大厅之后,仪门内大院落,上面五间大正房,两边厢房鹿顶耳房钻山,四通八达,轩昂壮丽”。堂屋中迎面“一个赤金九龙青地大匾,匾上写着斗大的三个大字,是‘荣禧堂’,后有一行小字:‘某年月日,书赐荣国公贾源’,又有‘万几宸翰之宝’。”屋内摆设有名贵的家具,珍贵的字画、古玩。“又有一副对联,乃乌木联牌,镶着錾银的字迹,道是:座上珠讥昭日月,堂前黼黻焕烟霞。”由堂屋进入东耳房,这里是起居室,另有一番布置,再到东廊三间小正房王夫人的住室,又别有摆设。
①平动的物体一般可以看作质点做平动的物体,由于物体上各点的运动情况相同,可以用一个点代表整个物体的运动,在这种情况下,物体的大小、形状就无关紧要了,可以把整个物体当质点。例如:平直公路上行驶的汽车,车身上各部分的运动情况相同,当我们把汽车作为一个整体来研究它的运动的时候,就可以把汽车当作质点。当然,假如我们需要研究汽车轮胎的运动,由于轮胎上各部分运动情况不相同,那就不能把它看作质点了。要注意的是:同一物体在不同情况下有时可看质点,有时不可以看作质点,一列火车从北京开到上海,研究火车的运行的时间,可将火车看成质点,而火车过桥时,计算火车过桥的时间,不可以将火车看成质点。②有转动但转动为次要因素例如:研究地球公转时,可把地球看作质点;研究地球自转时,不能把地球看作质点。③物体的形状、大小可忽略再如:乒乓球旋转对球的运动的较大的影响,运动员在发球、击球时都要考虑,就不能把乒乓球简单看作质点。
(创设实例:多媒体播放视频刘翔的110m栏。)1.提出问题:怎样定量(准确)人描述车或刘翔所在的位置?2.提示:你的描述必须能反映物体(或人)的运动特点(直线)、运动方向、各点之间的距离等因素。3.总结:①为了定量地描述物体的位置及位置的变化,需要在参考系上建立适当的坐标系。坐标系是在参考系的基础上抽象出来的概念,是抽象化的参考系。为了定量地描述物体的位置及位置的变化需要在参考系上建立适当的坐标系,如果物体在一维空间运动,即沿一条直线运动,只需建立直线坐标系,就能准确表达物体的位置;如果物体在二维空间运动,即在同一平面运动,就需要建立平面直角坐标系来描述物体的位置;当物体在三维空间运动时,则需要建立三维坐标系。①一维坐标:描述物体在一条直线上运动,即物体做一维运动时,可以以这条直线为x轴,在直线上规定原点、正方向和单位长度,建立直线坐标系。如图1-1-1所示,若某一物体运动到A点,此时它的位置坐标XA=3m,若它运动到B点,则此时它的坐标XB=-2m(“-”表示沿X轴负方向)。
(二)进行新课1、动能与势能的相互转化演示实验1:如右图,用细线、小球、带有标尺的铁架台等做实验。把一个小球用细线悬挂起来,把小球拉到一定高度的A点,然后放开,小球在摆动过程中,重力势能和动能相互转化。我们看到,小球可以摆到跟A点等高的C点,如图甲。如果用尺子在某一点挡住细线,小球虽然不能摆到C点,但摆到另一侧时,也能达到跟A点相同的高度,如图乙。问题:这个小实验中,小球的受力情况如何?各个力的做功情况如何?这个小实验说明了什么?学生观察演示实验,思考问题,选出代表发表见解。小球在摆动过程中受重力和绳的拉力作用。拉力和速度方向总垂直,对小球不做功;只有重力对小球能做功。实验证明,小球在摆动过程中重力势能和动能在不断转化。在摆动过程中,小球总能回到原来的高度。可见,重力势能和动能的总和保持不变。即机械能保持不变。
3.适用条件(1)万有引力定律只适用于质点间引力大小的计算。当两物体间的距离远远大于每个物体的尺寸时,物体可以看成质点,直接使用万有引力定律计算。(模型)研究相互接触的两个人之间的万有引力时,不能把他们看作质点。(2)当两物体是质量均匀分布的球体时,它们间的引力也可直接用公式计算,但式中的r是指两球心间距离。研究太阳和地球之间的万有引力,可以把它们看作质量均匀的球体。当研究物体不能看成质点时,可以把物体假想分割成无数个质点,求出两个物体上每个质点与另一物体上所有质点的万有引力,然后求合力,这是微积分的思想。万有引力定律产生于对太阳系行星运动的研究,但它对物质运动的适用性却要广泛得多。可以这样说,宇宙中凡有引力参与的一切复杂的现象,无不要归结到这样一条十分简洁的定律之中,这不能不使人惊叹宇宙万物超乎寻常的和谐及人类理性思考所具有的统摄力。
二、课堂教学(课前由科代表发回预习学案)1、教师根据预习学案检查结果提出问题(用多媒体展示),引导全班讨论(重点讨论:①、为什么动能的表达式一定是 mV2 ?你如何得出这个结论?②、力在一个过程中对物体所做的功,和物体在这个过程中动能的变化量有什么关系?你如何得出这个结论?这个做功的力和F=ma中的力F有什么关系)。有困难的小组应及时问老师。老师在这个过程中巡视指导。2、学生自主阅读课文“7 动能和动能定理”中的“动能的表达式”,然后完成如下练习(教师在此过程中巡视指导):2.1尝试推出动能的表达式(鼓励会推导的同学积极上台板演,老师引导讨论)。2.2写出动能的小结(认真阅读教材p66倒数第二段、第三段,结合你推导动能表达式的过程,认真思考后四人一组讨论:①、动能是矢量还是标量?②、动能的单位是什么?③、你认为应从哪几方面来理解动能?)
【学习内容分析】在行星运动规律与万有引力定律两节内容之间安排本节内容,是为了更突出发现万有引力定律的这个科学过程。如果说上一节内容是从运动学角度描述行星运动的话,那么,本节内容是从动力学角度来研究行星运动的,研究过程是依据已有规律进行的演绎推理过程。教科书在尊重历史事实的前提下,通过一些逻辑思维的铺垫,让学生以自己现有的知识基础身于历史的背景下,经历一次“发现”万有引力的过程,因此体验物理学研究问题的方法就成为主要的教学目标。【学情分析】在学太阳对行星的引力之前,学生已经对力、重力、向心力、加速度、重力加速度、向心加速度等概念有了较好的理解,并且掌握自由落体运动和圆周运动等运动规律,能熟练运用牛顿运动定律解决动力学问题。已经完全具备深入探究和学习万有引力定律的起点能力。所以在推导太阳与行星运动规律时,教师可以要求学生自主地运用原有的知识进行推导,并要求说明每一步推理的理论依据是什么,教师仅在难点问题上做适当的点拨。
“做功的过程就是能量转化过程”,这是本章教学中的一条主线。对于一种势能,就一定对应于相应的力做功。类比研究重力势能是从分析重力做功入手的,研究弹簧的弹性势能则应从弹簧的弹力做功入手。然而弹簧的弹力是一个变力,如何研究变力做功是本节的一个难点,也是重点。首先,要引导学生通过类比重力做功和重力势能的关系得出弹簧的弹力做功和弹簧的弹性势能的关系。其次,通过合理的猜想与假设得出弹簧的弹力做功与哪些物理量有关。最后,类比匀变速直线运动求位移的方法,进行知识迁移,利用微元法的思想得到弹簧弹力做功的表达式,逐步把微分和积分的思想渗透到学生的思维中。本节课通过游戏引入课题,通过生活中拉弓射箭、撑杆跳高和弹跳蛙等玩具以及各种弹簧等实例来创设情景,提出问题。给学生感性认识,引起学生的好奇心;让学生对弹簧弹力做功的影响因素进行猜想和假设,提出合理的推测,激发学生的探索心理,构思实验,为定性探究打下基础。然后,引导学生通过类比重力做功与重力势能的关系得出弹簧弹性势能与弹簧弹力做功的关系。
说明:“倍增法”是一种重要的物理方法,历史上库仑在研究电荷间的相互作用力时曾用过此法,但学生在此前的物理学习中可能未曾遇到类似例子,因此引导学生通过交流,领会“倍增法”的妙处,这是本节课的一个要点.可用体育锻炼中的“拉力器”来类比。(2)该方案消除摩擦力影响的方法:所用的消除方法与实验方案2一样。也可使用气垫导轨代替木板,以更好地消除摩擦影响。(3)小车速度的确定方法:①确定打出来的点大致呈现什么规律:先密后疏(变加速),再均匀分布(匀速);②应研究小车在哪个时刻的速度:在橡皮筋刚恢复原长时小车的瞬时速度,即纸带上的点刚开始呈现均匀分布时的速度;③应如何取纸带上的点距以确定速度:由于实验器材和每次操作的分散性,尤其是橡皮筋不可能长度、粗细完全一致,使得每次改变橡皮筋的条数后,纸带上反映小车匀速运动的点数和点的位置,不一定都在事先的设定点(即用一条橡皮筋拉小车,橡皮筋刚好恢复原长时纸带上的点)处。
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