第一篇:2017--2018学年人教版必修一Unit 4 earthquakes reading教案
Unit 4 earthquakes reading教案 A Night the Earth Didn’t Sleep
Teaching Plan Teaching Aims: 1.Learn about the Tangshan earthquake.2.Develop the students’ reading ability 3.Learn to care for others.Teaching Important and Difficult Points: Help the students to grasp key information while they are reading.Teaching Methods: 1.Task-based methods to get the students to understand the passage.2.Pair work and group work to make the students work in class.Teaching Aids: 1.OHP 2.the blackboard Teaching Procedures: Step 1.Revision Go over the new words learned in the previous lesson.Step 2.Lead-in 1.The teacher shows a series of pictures of some disasters on the screen and let the students name them.(The pictures are about a fire, a hurricane ,a tsunami, an earthquake and so on.)2.The teacher shows a picture of new Tangshan to the students.Then asks the students to describe what they see.3.The teacher shows another picture of Tangshan(the city after the earthquake), and gets the students to guess what happened and what damage it caused.Step 3.Fast reading 1.Skim the passage and divide the passage into 3 parts.2.Sum up the main idea of each part.Part 1(para.1): Before the earthquake, strange things happened.Part 2(paras.2-3): During the earthquake, the city was destroyed.Part 3(para.4): After the quake, people saw hope.Step 4.Careful reading Let the students read the passage carefully and finish the tasks below.1.Listen and tell whether the statement is True or False.(1)People in Tangshan were warned of the earthquake and didn’t go to bed.(2)People in Beijing also felt the earthquake.(3)More than 4000 000 people were killed in the quake.(4)Many rescue workers and doctors were trapped under the ruins during the aftershock.(5)People tried to get fresh water from under the ground in Tangshan.Answers: F T F T F 2.Do the exercises in students’ book on page 27.(1)Exercise 2.(2)Exercise 1 Step 5.Pair work Suppose one of you are a CCTV reporter, and the other was a witness of the 1976 Tangshan Earthquake.Now you are having a face-to-face interview.Please work in pairs.Step 6.Discussion After the terrible disaster, many children became homeless.Please work in group and discuss what we can do for them.Step 7.Conclusion
A Night the Earth Didn’t Sleep is a news report.It talks about the 1976 Great Tangshan Earthquake.The 1976 Great Tangshan Earthquake, which had many early signs, destroyed the city and shocked people very much, but rescue soon came and people saw hope for a new life.What can we learn from this report? We must care for those who are in trouble.We must do our best to help those who need help.The PLA man and the rescue doctors set us a good example.Step 8.Homework
Read the passage again and write a short passage about the 1976 Tangshan earthquake.
第二篇:人教高中生物必修一细胞癌变教案
第6章 第4节 细胞的癌变
一、知识教学点:
1、说出癌细胞的主要特征和致癌因子。
2、讨论恶性肿瘤的防治,选择健康的生活方式。
二、能力训练点:
1、通过学生在解决实际问题的过程中理解生物学的基本概念,培养学生的理解能力以及从课文中提取信息的能力。
2、通过对癌症的预防措施的讨论,让学生亲历思考和探究的过程,领悟研究方法,养成尊重事实的研究态度和能力,以及应用理论知识解决实际生活问题的能力。
三、德育渗透点:
1、通过癌症的致死率高的学习,激发学生对细胞癌变的关注,从而确立积极的生活态度和健康的生活方式。
2、通过致癌因子的讨论,引导学生认识到吸烟的危害,以及增强爱护环境的意识。
四、美育渗透点:
通过本节课的学习,让学生认识到生命的美,从而感知生命的珍贵。
五、学科方法训练点:
1、结合本课内容,引导学生联系实际生活,发现问题、探究问题、解决问题。
2、对学生进行口头表述能力的训练。
六、教学重点:
1、癌细胞的主要特征。
2、致癌因子。
七、教学难点:
原癌基因与抑癌基因的区别。
八、课时安排:1课时
九、教具:多媒体平台
十、教学设计:
(一)教学方法:启发式讲授法、直观教学法、小组合作学习法
(二)教学过程
1、课前准备
制作PowerPoint演示文稿
2、情景导入
播放一个细胞的生长、增殖、衰老、凋亡的过程动画。从动画中学生深刻认识到细胞是有一定寿命的,细胞的生长、增殖、衰老、凋亡是细胞的正常生理过程。人没有长生不老,细胞有长生不老吗?当今世界人们谈癌色变,患病的原因是什么?这节课我们将围绕这些问题展开讨论。
3、师生互动
〖提问〗在我们身边时常听到有关癌症的情况,就你所知,你听说过哪些癌症?
〖学生回答〗肝癌、肺癌、胃癌、肠癌、食管癌、宫颈癌、鼻咽癌、乳腺癌、皮肤癌、血癌(白血病)、脑癌、前列腺癌、舌癌等等。
〖问题探讨〗同学们回答的很好,下面我们来看书上的问题探讨。(学生思考回答,教师提示。)
〖提示〗
(1)日光浴使皮肤生发层细胞中的胆固醇在紫外线照射下转化成维生素D,可以预防佝偻病、骨质疏松症;同时在紫外线的照射下,表皮细胞可以产生黑色素,保护内部组织和器官。
2(2)首先尽量不在紫外线强烈辐射的时间和地点长时间进行日光浴。不同的地区由于经纬度不同,因而日照强度过强的时间长短不同。可以引导学生调查当地的紫外线辐射的情况。其次涂上防晒霜,可以在一定程度上减弱紫外线辐射对皮肤的伤害。然后使用防紫外线遮阳伞,可以适当减少紫外线辐射。
(3)臭氧层可以部分吸收紫外线。当臭氧层被破坏时,过多的紫外线辐射有可能伤及表皮细胞中的遗传物质,严重时可能导致皮肤癌。
〖提问〗通过前面的学习,我们知道细胞是会分裂和分化的,细胞的分裂和分化如果出现异常将会造成什么后果呢?
〖板书〗癌细胞:有的细胞受到致癌因子的作用,细胞中遗传物质发生变化,就变成不受机体控制的、连续进行分裂的恶性增殖细胞,这种细胞就是癌细胞。
〖提问〗那么癌细胞与正常细胞有哪些区别呢?
〖看课件〗播放正常细胞与癌细胞的图片,启发学生回答: 癌细胞与正常细胞的区别是:
①恶性增值的“不死的细胞”:能够无限增值; ②形状显著改变的“变态的细胞”:形态结构变化;
③黏着性降低的“扩散的细胞”:癌细胞表面糖蛋白减少,使得细胞之间的黏着性减少,因此癌细胞容易在机体内分散和转移。
〖提问〗(分四小组,每组讨论一个问题)(1)引起细胞癌变的致癌因子有哪些?(2)细胞为什么会发生癌变?(3)原癌基因与抑癌基因的区别?
(4)怎样预防癌症的发生?(教师巡查指导,待学生讨论分析后由学生回答,教师归纳)
〖代表发言〗各小组组长代表发言汇报,经过全体同学的质疑和探讨后得出:
一、致癌因子
⑴物理致癌因子:主要指辐射,如紫外线、X射线、电离辐射等。⑵化学致癌因子:无机物如石棉、砷化物、铬化物、镉化物等;有机物如黄曲霉素、亚硝胺、联苯胺、烯环烃等。
⑶生物致癌因子:如Rous肉瘤病毒。
〖练习〗根据以下案例分析是哪种致癌因子引起的癌症?(1)二战时日本受原子弹爆炸影响,幸存居民经29年观察,发现白血病发生率明显增高,距离爆炸中心越近,发生率也越高。(物理致癌因子)
(2)
3、4-苯并芘是煤焦油的主要成分,近几十年来肺癌的发生率增加,可能与烟草燃烧的烟雾、工厂的煤烟、汽车的废气等气体有关。(化学致癌因子)
(3)有人用砷酸钠治疗皮肤病后,出现局部色素增加,过度角化,最后发展为皮肤癌,砷是唯一能使人类致癌而动物不致癌的物质。(化学致癌因子)
二、癌症的发生是基因突变的累积效应。环境中的致癌因子会损伤细胞中的DNA分子,使原癌基因和抑癌基因发生突变,导致正常细胞的生长和分裂失控而变成癌细胞。细胞的畸形分化,与癌细胞的产生有直接关系。
三、细胞中既有原癌基因,又有抑癌基因,其中原癌基因主要负责调节细胞周期,控制细胞生长和分裂的进程。抑癌基因则主要是阻止组织细胞不正常的增值。
四、在个人日常生活中注意远离物理、化学和病毒致癌因子;同时要注意增强体质,保持心态健康,养成良好的生活习惯,从多方面 4 采取防护措施。
〖资料分析〗健康的生活方式与防癌。学生思考讨论回答,教师提示。
〖提示〗(1)“病从口入”也适用于癌症。发霉的、熏制的、烧烤的以及高脂肪的食品中含有较多的致癌物质,如黄曲霉素、亚硝酸盐、苯并〔α〕芘等。
(2)物理的,化学的,生物的。
4、小结
(1)癌细胞的主要特征:①恶性增值的“不死的细胞”;
②形状显著改变的“变态的细胞”; ③黏着性降低的“扩散的细胞”。
(2)致癌因子:物理、化学、病毒致癌因子。
(3)原癌基因和抑癌基因的区别:原癌基因主要负责调节细胞周期,控制细胞生长和分裂的进程。抑癌基因则主要是阻止组织细胞不正常的增值。
(4)预防癌症发生的措施:在个人日常生活中注意远离物理、化学和病毒致癌因子;同时要注意增强体质,保持心态健康,养成良好的生活习惯,从多方面采取防护措施。
5、随堂练习
(1)癌细胞形成的根本原因是()
A、细胞内原癌基因的激活 B、物理致癌因子的刺激 C、化学致癌因子的刺激 D、病毒致癌因子的刺激(2)检测某一植物组织,发现其分解有机物速率减慢,且细胞萎缩。该细胞正在()
A、分化 B、分裂 C、衰老 D、癌变(3)下列哪组是细胞癌变的特征()
① 细胞无限分裂 ②水分减少 ③畸形改变 ④酶活性减低 ⑤色素沉着 ⑥易分散转移 ⑦呼吸速率减慢 ⑧细胞膜通透性改变
A、①③⑥ B、①②⑤⑦ C、②④⑤⑦⑧ D、②④⑥⑧
(4)当今世界严重威胁人类生存的细胞变化是()A、细胞增值 B、细胞分化 C、细胞癌变 D、细胞衰老
(5)癌细胞具有的特征中,不正确的是()
A、能无限增值 B、形态与结构出现畸形变化
C、细胞表面发生变化 D、能进行正常的细胞分化(6)当人的成纤维细胞由扁平梭形变成球形时,说明该细胞已经完成()
A、细胞分裂 B、细胞分化 C、细胞癌变 D、细胞衰老
A C A C D C
6、作业:练习一二。
〖提示〗基础题1.(1)√;(2)√。
2.癌细胞的特点:细胞增殖失控,能够无限增殖;细胞的形态结构发生显著变化;容易在体内分散和转移。
拓展题
1.提示:不都是。如果早发现,有些癌症完全可以通过手术切除、化疗或放疗治愈,如乳腺癌、胃癌、肠癌等。
2.提示:(1)被动吸烟也可能导致肺癌。(2)其他因素可能导致肺癌。
第三篇:人教新课标必修一 Unit1 Friendship[全套教案]
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Unit 1 Friendship Teaching goals:
*语言知识
1.to talk about friends and friendship, and interpersonal relationship 2.to practise expressing attitudes, agreement and disagreement, and certainty 3.to master some sentences about giving advice 4.to learn to use the Direct Speech and Indirect Speech(1): statements and questions 5.to learn about communication skills
*语言技能和学习策略
1.to develop listening skills by doing exercises in listening task 2.to develop speaking skills by finishing the speaking task and other activities like discussion and oral practice 3.to develop reading skills through the reading materials in this unit 4.to learn to write a letter of advice
*文化意识
1.to know about friend and the real meaning of friend 2.to learn how to get along with others
*情感态度
1.to arouse the interest in learning English 2.to learn to express their feeling of friends and friendship
Teaching key points: 1.how to improve students’ speaking and cooperating abilities
2.learn to use the Direct Speech and Indirect Speech(1):statements and questions 3.master some words and expressions Teaching difficult points: 1.train the students’ speaking, listening, reading and writing abilities 2.how to improve students’ cooperating abilities Teaching methods: Student-focus approach and task-based approach Learning methods: Cooperative study Teaching aids: Computer
The First Period(Warming up &Speaking)Teaching aims: 1.to know about different kinds of friendship 嘉兴英语教学网 www.xiexiebang.com 收集整理
2.to learn some words of describing friend and friendship 3.to master some useful words and expressions Teaching methods: 1.discussing
2.cooperative learning
Teaching materials: Warming up Teaching procedures: Step One: Leading-in 1.Free talk: Something about friend and friendship Ask the Ss to describe one of their friends----their appearance, personality, hobbies, etc.Qs: What’s your friend like?
What does he/she like to do in his/her spare time?
What personality does he/she have? Step Two: Discussion
1.Writing the following statement on the blackboard We all agree that to have a good friend , you need to be a good friend.2.Ask the Ss: What do you think of this statement and how can you be a good friend? Let the Ss express their views 3.Have the Ss get into groups of four to list some qualities of a person they would like as a friend.Ss may list: honest, friendly, open-minded, generous, helpful, patient, good-tempered, trustworthy, careful, full of love, caring, responsible, interesting, brave, easygoing, outgoing, warm-hearted, kind, selfness, tolerant, intelligent… 4.Have a member of each group report on what their lists have and list them on the blackboard 5.Ask the class whether or not they agree with all the qualities listed Step Three: Doing the survey and explanation 1.Have the Ss do the survey in the textbook and let them work out their score.2.Teacher explain each item Question 1 deal with how thoughtful you are towards others.The scoring reflects your concern for others.So one point for A gets the lowest score because it is the most selfish response.B get the highest score because it show a concern for your friend as well as your wish to go to see a film.C gets a slightly lower score because although it shows you want to go with your friend(because you change the plan), you do not help your friend.Question 2 is concerned with fairness.A gets the lowest score because you are not giving your friend another chance to behave better this time.B gets a higher score because you let your friend borrow the camera again.This shows kindness and forgiveness or the trouble you had when it was returned broken.But you are not balancing his heeds against your own.That is why C gets the highest score.You are showing your friend that you will trust him/her with the camera again but this time you are giving him / her rules in case it gets broken.嘉兴英语教学网 www.xiexiebang.com 收集整理
Question 3 deals with your concern for others.A get the lowest score because you would put anything else that needed to be done aside and concentrate only on your friend.This is not responsible.You have things that you need to do.Of course your friend is important but not more important than you responsibilities.B gets a higher score because it shows some concern for your friend and some understanding that you have important things to do too.But it does not show any real interest in his / her problem.C get the highest score because it not only shows concern for your friend but a recognition that you have responsibilities too.Question 4 is concerned with responsibilities to a friend.A provides the correct amount of responsibility to your friend.You recognize that it was your fault and will put it right and pay for the damage.So it gets the highest score.B provides some understanding that you are responsible.You put the situation right but you do not pay for the damage yourself.So it does not get the highest score.C gets the lowest score because you expect your friend to pay for your mistakes even though you were doing your friend a favour.Question 5 is concerned with honesty.If you let your friend look at your paper or somebody else’s paper, you are helping them to cheat.That is not honest, so answers A and C get no marks.But it takes courage to tell your friend that they should have studied and that they cannot look at your paper.That is also the honest answer.So you get 6 points for B, which is more than any other in the quiz.Step Four: Language points Teacher explain language points with some slides 1.add v.1)to put together with something else so as to increase the number, size, importance, etc.增加,添加
eg.Please add something to what I’ve said, John.2)to join numbers, amount, etc so as to find the total eg.Add up these figure for me, please.常用结构:
add up / together sth.把…加起来,合计 add sth.to sth.把…加到/进 add to(=increase)增加了… add up to 合计,共计 add in 包括…,算进
2.pay to get it repaired
花钱让人去修理
3.upset
adj.worred;annoyed 不安的;使心烦意乱的
v.cause to worry, to be sad, to be angry, not to be calm, etc.使不安;使心烦意乱
eg.He was upset when he heard the news.His cheating in the exam upset his teacher.4.ignore vt.to pay no attention to sth.忽视;对…不予理睬 eg.Ignore the child if he misbehaves and he’ll stop soon.ignorant adj.无知的;不知的 ignorance n.无知;愚昧 嘉兴英语教学网 www.xiexiebang.com 收集整理
5.calm
vt.to make sth./ sb.become quiet 使镇静;使平静
adj.not excited, nervous or upset 镇静的;沉着的
calm down 镇静;平静
calm down sb.=calm sb.Down
使某人镇静 sb.calm down(vi.)
某人平静下来 eg.The excited girl quickly calmed down.He took a few deep breaths to calm himself down.6.have got to do sth.(口语)=have to do sth.不得不做某事;必须做某事
eg.Since you’re no longer a child now, you have got to make money to support the family.*have got to在变疑问句或否定句时,不再另加助动词,而have to则须加助动词do.have got to前不用情态动词,而have to前则可以。如: eg.Have you got to writ an assignment for your teacher? 7.be concerned about / for : be worried about eg.We’re all concerned about her safety.8.cheat
vt.1)to act in a dishonest way in order to win
欺骗;作弊
eg.Any student caught cheating will have to leave the classroom.2)to take from(someone)in a dishonest way 骗;骗取
eg.They cheated the old woman(out)of her money by making her sign a document she didn’t understand.n.1)an act of cheating
作弊行为
2)one who cheats
骗子
Step Five: Speaking 1.Get the Ss to work in groups of 4.2.Ask the Ss to use the questionnaire in Warming up as an example and discuss about designing questions.3.Follow the steps in this part and start the discussion like this: A: Now let us design a questionnaire to find out what kind of friend one is.B: OK.First we must think of four questions and three possible answers to each question.C: What about the first question? Have you got one in mind? D: Suppose your friend has taken away your book by mistake.What will you do or say to him / her? …
4.Teacher go around in the classroom and check their discussion.Step Six: Assignments 1.Ask Ss to consider the following question;What is / are the most important quality / qualities that a friend needs to have? 2.Prepare for Reading
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The Second and Third Period
(reading and language points)Teaching aims:
1.to know about the story of Anne’s Diary
2.to promote the Ss’ abilities of reading comprehension 3.to learn about the following words and expressions: readon;list;go through;hide away;set down;a series of;outdoors;crazy;spellbound;on purpose;dare;happen to do sth.;It’s the first time that… Teaching methods: 1.reading and discussion 2.cooperative learning and speaking Teaching materials: Reading, Comprehending Teaching procedures: Step One: Leading-in Ask their opinions on the question mentioned in the assignment of last period.Step Two: Pre-reading Let the Ss think about the questions in Pre-reading, and express their own views to the whole class.Step Three: Reading
1.Ask the Ss to look at the pictures and the heading, guess what the text might be about.2.Get the Ss to skim the passage and answer the following questions: What’s Anne’s best friend?
What does her diary mainly talk about?(1.Anne’s best friend is her diary.2.It’s about Anne’s feeling of hiding away.She especially missed going outside and enjoying nature.3.Let the Ss read the passage and discuss the following questions: 1)Imagine what it might be like if they had to stay in their bedroom for a whole year.You could not leave it even to go to the WC or get a cup of tea.How would they feel? 2)If you are only allowed to have five things with you in the hiding place because there is very little room, what would you choose? 3)Try to guess why the windows had to stay closed.4)Guess the meanings of the word “crazy” and “spellbound” according to the context.Step Four: Discussing the style Ask the Ss: 1.What do you think is the purpose of this passage? Why did Anne write it? 2.Do you think it is successful? Do you understand Anne’s feelings?
3.What is Anne’s tone? In other words, is the author angry, sad, happy or thrilled? 4.What is Anne’s point of view? Do you agree with it? If so, why? If not, why not? Step Five: Listen to the text and comprehend it Step Six: Language points 1.go through 嘉兴英语教学网 www.xiexiebang.com 收集整理
1)to examine carefully
仔细阅读或研究 eg.I went through the students’ papers last night.2)to experience 经历;遭受或忍受
eg.You really don’t know what we went through while working on this project.2.hide away 3)vi.to go somewhere where you hope you will not be seen or found 躲避;隐匿
hide away +地点
eg.The thief hid away in a friends’ house for several weeks after the robbery.4)to put or keep sth./sb.in a place where they / it can’t be seen or found 藏;隐蔽
hide away sth./ hide sth.away eg.Why do you hide your thoughts away from me? 3.set down 5)write down 写下;记下
eg.I’ll set down the story as it was told to me.6)put down 放下;搁下 set down sth./set sth.down eg.He set down a basket on the ground.4.series
n.(单复数同形)
a series of 一连串的;一系列的 5.crazy
adj.7)mad, foolish 疯狂的;愚蠢的
It is crazy of sb.to do sth.= sb be crazy to do sth.eg.It’s crazy to go out in such hot weather.8)wildly excited;very interested 狂热的;着迷的 grow / be crazy about sb./ sth.eg.The boys are crazy about the girl singer.9)like crazy 发疯似的;拼命地
eg.He talked like crazy;I couldn’t understand what he said.6.I wonder if it’s because I haven’tt been able to be outdoors for so long that ….*I wonder if / whether…
eg.I wonder if you can help me? *It’s because …
it is 后的表原因的从句中,只能用because来引导,不能用since或as.eg.Why did you go to school on foot?
It is because my bike had broken.7.spellbind
v.to hold the complete attention of 吸引人,迷人;使入迷
eg.The children watched spellbound as the magician took rabbits from his hat.9.stay
v.to continue to be in a particular state or situatioin 系动词,表是状态。后跟名词或形容词,不能用于被动语态和进行时态。eg.He stayed single all his life.10.on purpose 嘉兴英语教学网 www.xiexiebang.com 收集整理
1)故意地(反义:by chance / accident)
eg.I think she lost the key on purpose.2)on purpose to do sth.为了要…而特地
eg.He went to town on purpose to sell one of his paintings.10.far
adv.“过于;…得多” ,表示程度,经常与too或形容词、副词的比较级连用。
eg.She speaks English far better than I.This room is far too warm.cf.very, much, far 11.dare 1)modal.v.多用于否定句、疑问句、条件状语从句、whether(if)等名词性从句或有否定意义的句中,后接动词原形。没有人称和数的变化,其时态只有现在时和过去时。否定式在其后加not.eg.How dare he say such a word!
If you dare do that again, you’ll be punished.2)vt.敢,胆敢。有人称、数和时态的变化。在否定句和疑问句中,dare后的to可保留也可省略。
eg.I wonder how he dare to day such words.12.happen to do sth.It so(just)happened that… 不能用于进行时态。
eg.I happened to be out when he came.= It so happened that I was out when he came.13.It’s the first time that…
eg.It is the first time that I have seen the sea.Step Seven: Comprehending Get the Ss to do the exercises in this part.Step Eight: Consolidation Listen to the text again to appreciate it.Step Nine: Assignments 1.Read the key sentences in the text 2.do the exercises on Wb(Page 41-42)
The Fourth Period(Listening)Teaching aims: to train and develop listening skills by listening to the listening exercises in this unit Teaching methods: Listening and speaking Teaching materials: listening parts on Page 6 and Page 41 and Page 43 Teaching procedures: Step One: Revision Check the answers to the homework Step Two: Listening 1.Listen to the exercises on Page 6 嘉兴英语教学网 www.xiexiebang.com 收集整理
2.Guess the words by listening to the tape and write them down Step Three: Listening to the passage Fill in the blanks on Page 41 Step Four: Speaking
Listen to the tape and discuss questions in groups of four, express your own views.Step Five: Listening task 1.Discuss with the Ss whether they always do what their parents tell them.2.Have the Ss listen to the passage.3.Fill in the table
4.Work in pairs to give some advice to Anne Step Six: Assignments 1.Do the exercises on Page 42(Ex 1,2)2.Revise the Object Clause
The Fifth Period(Discovering Useful Structures)Teaching aims: Let the Ss use the Direct Speech and Indirect Speech Teaching methods: 1.discovery learning 2.cooperative learning Teaching materials: Page 5 Teaching procedures: Step One: Revision 1.Check the homework with the Ss 2.Revise the Object clause
Exercise: Rewrite the following sentences.1.I go to school by bike.(He said…)
2.Will you forget to do your homework?(Mary asked him…)3.When did you come here?(They asked me…)4.What has he said?(Do you know…)
5.Anne is watching TV now.(Mother told me …)Step Two: discovering useful structures 1.Present some sentences for Ss
1)My friend says, “ I will come here tomorrow?”
如果此时此地,你来转述,应该说:
My friend says she / he will come here tomorrow? 如果时间变了,地点不变,你来转述,应该说: My friend said she / he would come here the next day.如果地点变了,时间还是今天,你来转述,应该说: My friend sayd she / he will go there tomorrow.如果时间地点都变了,你来转述,应该说: My friend said She / he would go there the next day.嘉兴英语教学网 www.xiexiebang.com 收集整理
如果由别人转述,时间地点都变了,应该说:
He/ She said he /she would go there the next day.*使用直接引语和间接引语要注意具体语境。
2)“Do you go to the park yesterday?” He asked me.He asked me if / whether I went to the park the day before.3)Kate said to John, “What’s your favourite food?”
Kate asked John what his favourite food was.2.Get the Ss to have a look at Part 1 in “Discovering useful structures” and sum up this grammar point.人称、时态、指示代词、时间状语、地点状语等的变化。Step Three: Practice 1.Do the first tow sentences in Part 2 as examples.2.Check the answers together.Step Four: Assignments 1.Wb, Page 42, 43(Individual, Groups)2.Prepare for Reading on Page 44
The Sixth Period(Reading)Teaching aims:
1.to learn about friendship in Hawaii 2.to promote the Ss’ abilities of reading comprehension 3.to learn about the following words and expressions: way;the second important;It’s believed that…;in peace;those who …;etc.Teaching methods: 1.reading and discussion
2.cooperative learning and speaking Teaching methods: Reading(Page 44)Teaching procedures: Step One: Leading-in
1.Ask the Ss if they can think of any place in the world where Chinese and Western cultures live side by side.(Hong Kong, Macao, Singapore, the Philippines, San Francisco, etc.)Step Two: Reading 1.Get the Ss to read the passage and try to finish the table in Ex1.2.Read the passage carefully again and discuss the questions in Ex2.3.Report their discussion Step Three: Listening to the text and comprehend it Step Four: Language points 1.the way to do sth./ the way of doing sth.2.the second most important the second + adj.(最高级)the third + adj.(最高级)
eg.The Yellow River is the second longest river in China.嘉兴英语教学网 www.xiexiebang.com 收集整理
China is the third largest country in the world.3.to enjoy the land = in order to enjoy the land eg.To make the w8th Olympic Games the game ever, Beijing will make several changes.* to do和 in order to do可以置于句首、句末,而 so as to do只能置于句末。4.Indeed, Hawaii is a place where ….small communities.5.It’s believed that the islands can be a paradise ….It’s believed that …= People believe that …
eg.It’s believed that they arrived more than 30,000 years ago.6.in peace 7.… they are really talking about all those who live on the islands.those who…=people who … “凡…的人”
eg.The teacher praised those who had done good deeds.We find it our duty to help those who are in trouble.8.Living in peace, Hawaiians has developed …
现在分词短语作原因状语,相当于 As they are living in peace.9.Perhaps this is how most visitors will remember their new friendship.Step Five: Listening to the text and enjoy it
The Seventh Period(Speaking Task and Writing)Teaching aims: 1.to develop Ss’ speaking ability and learn to express their own views 2.enable Ss to write a letter of advice Teaching methods: 1.tasked-based learning 2.speaking Teaching procedures: Step One: Speaking task Task One: Ex1(Page 45)1.Get the Ss to work in pairs, have them read the situations and choose one to discuss.2.Ask the Ss to present their dialogue.Task Two: Ex2(Page 45-46)1.Ask the Ss to look at the pictures.2.Work in groups of four and talk about whether they are doing is cool or not.3.Try to express their own views to the whole class.Step Two: Writing
Task One: Ask the Ss to write a letter of advice 1.Get the S to read the letter on Page 7 and understand it.2.Ask the Ss to work in pairs and talk about how to answer the letter.3.Write the letter in reply down.10 嘉兴英语教学网 www.xiexiebang.com 收集整理
Task Two: Ask the Ss to write a passage about their opinions on friend and friendship 1.Read the proverbs carefully.2.Write a passage to express their own opinions.Step Three: Assignments 1.Fill in the form in Sum up(Page 8)2.Fill in the form in Checking yourself(Page 47)11
第四篇:精品教案--人教必修1 抗日战争
高中历史必修一《抗日战争》教学案例
一、《课标》内容标准
“列举侵华日军的罪行,简述中国军民抗日斗争的主要史实,理解全民族团结抗战的重要性,探讨抗日战争胜利在中国反抗外来侵略斗争中的历史地位。”
二、教学目标
1、知识与能力:
(1)识记:七七事变、抗日民族统一战线的建立、正面战场与敌后战场的抗战、日军侵华的滔天罪行、抗日战争胜利的基本事实。
(2)理解:抗日民族统一战线形成的原因及过程;比较分析抗战初期两个战场的抗战;全面分析抗战胜利的原因,尤其是抗日民族统一战线的作用;抗战胜利的历史意义。
(3)运用:结合当前时事分析历史与现实的联系,思考战争给中日两国带来的影响。
2、过程与方法:
通过播放有关录象和历史图片,创设历史情境,让学生置身于抗日战争的特定背景中,去探究日军侵华和中国军民抗战这两方面的问题;通过提供材料让学生获取有效信息,培养学生从不同角度认识问题和论从史出的学习方法。
3、情感态度与价值观:
(1)日本帝国主义发动的侵华战争给中国人民带来了深重的灾难,学习本课历史激发学生的民族自豪感、历史使命感,树立强国之志。
(2)中国人民的抗战是“民族抗战”,以此培养和发扬学生的民族精神和爱国主义情感,形成对国家、民族的历史使命感和责任感,为建设中国特色社会主义做贡献。
三、教学准备
搜集与抗战相关的图片、影视资料和相关文字材料等信息,制作多媒体课件。
四、学情分析
由于初中生对抗日战争史的学习比较充分,学生对抗日战争的主要史实比较熟悉,但是主要停留在感性认识阶段,高中教学要在引导学生回顾抗日战争的基本史实的基础上,加强对抗日战争胜利原因和历史地位及以史为鉴、开创未来的理性思考。
五、教学方法:
本课采用“回顾—讨论—探究—反思”的互动教学模式,以史实为基础,以问题为载体,以情境为主线,以多媒体为辅助手段,以活动为实现方式,师生互动,生生互动,经过全体课堂参与者的阅读、思考、讨论,使每个学习者都经历一个主动的获取知识、解决问题、完善情感、升华人格的自主学习过程。
六、重点、难点
重点:日军的滔天罪行、全民族的抗战、抗战胜利的原因和地位。
难点:抗战胜利的原因和地位。
七、课时安排:1课时
八、板书设计
教学过程 导入新课:
播放《义勇军进行曲》。刚才大家听到的这首高亢激昂的歌曲是——(学生回答:《义勇军进行曲》。)我们每周升国旗仪式必唱的国歌,多么熟悉的旋律。《义勇军进行曲》创作于1935年,“中华民族到了最危险的时候”,主要是因为什么?(日本侵略,民族危机严重)中华民族当时的主要任务是什么?(抗日救亡)让我们共同走进那不堪回首的岁月,走进伟大的抗日战争。
本节课我们通过回顾历史、探究历史和感悟历史三个主题来纪念伟大的抗日战争。
一、回顾历史——血腥野蛮地侵略
1、侵华事变:
(由于高中生对抗战史的主要事实比较清楚,本目主要采取学生回顾的方式进行。)二十世纪三四十年代,日本帝国主义对中国进行了最惨无人道的野蛮侵略,同学们,你们在初中已经学习过抗日战争史,请你们回顾:日本帝国主义在三四十年代对中国发动了哪些侵华事变?对中国人民犯下了哪些滔天罪行?
在学生回答后,课件打出:《中华民国图》,在图中相应位置闪动出现九一八事变、一二八事变、伪满洲国、华北事变、七七事变等侵华事变,中国大片国土沦丧,中华民族到了最危险的时候。
【思考】:“小”日本为何侵略“大”中国?
(1)历史原因:从大陆政策到“国策基准”(课件打出“国策基准”的材料)。
(2)经济原因:自然条件的限制;摆脱经济危机。
(3)外部原因:国际社会的绥靖之风和国共内战。
(过渡)日本帝国主义在侵华过程中犯下了滔天罪行。
2、滔天罪行:
南京大屠杀:出示相关图片如累累白骨、杀人比赛(向井和野田在进南京城前谁先杀100人,野田杀了105人,向井杀了106人),突出遇难者300000人。
(请同学有感情地朗诵下列这首诗)
凝视300000,——
“3”后面是一个个“o”(零)吗?
不——分明是一颗颗屈死的头颅,正面对屠刀,怒目相看!
凝视300000,——
“3”后面是一个个“0”(圈)吗?
不——分明是一根根高悬的绞索,东条英机们 ,不正吊死在耻辱柱上?!
凝视300000,——
字字在喷火,声声在呐喊:
多行不义必自毙,血债定要用血来偿还!
3、潘家峪惨案:现场一角等图片,死难者1200余人。
4、七三一细菌部队:出示活体实验、2003年中毒后李贵珍等相关图片。
27万——侵华日军实施细菌战致死中国民众27万多人(日本学者认为,这是相当保守的数字,他们认为,死于侵华日军细菌战的中国人多于日军于1937年在南京制造的大屠杀人数);
3000公斤——侵华日军“731部队”每年可以生产出3000公斤的纯细菌(每135克的纯细菌就可以使400平方公里之内的所有水源遭到污染,每年的生产量足以污染全中国的水源);
3000人——侵华日军“731”部队用活人作试验人数(仅日方承认的);
【讨论】同学们在看了这些图片之后一定深有感触,请用一句话表达你此时的心情(学生回答)。【学思之窗】是什么使他们从人变成了野兽?
(武士道精神、灭亡中国,泯灭中国人民的抗战意识)。
我们经常说,中日两国是一衣带水,我要说在中国近代史上,中日两国是一衣带血。日本帝国主义侵略者自1931年“九一八”事变至1945年战败投降,在长达14年的侵华战争中,在中国广大的土地上,以最野蛮、最残暴、最惨绝人寰、最没有人性的手段进行着大破坏、大屠杀,对中国人民犯下了滔天罪行。神州在流血,中华在哭泣。偌大的中国乌云密布,哀鸿遍野。泱泱中华,面临亡种灭国的危机。
作为一个中国人,作为那个时代有血性的中国人,你该怎么做(学生回答)?
“国破尚如此,我何惜此头!”
课件打出:以下材料
材料一 全中国同胞,政府,与军队,团结起来,建筑民族统一战线的坚固长城,抵抗日寇的侵掠!国共两党亲密合作驱逐日寇出中国!
——中国共产党为日军进攻卢沟桥通电
(1937年7月8日)材料二 我们希望和平而不求苟安,……如果战端一开,就是地无分南北,年无分老幼,无论何人,皆有守土抗战之责任,皆应抱定牺牲一切之决心。
——蒋介石庐山谈话(1937年7月17日)
国共两党捐弃前嫌,共赴国难,实现了第二次国共合作,建立了抗日民族统一战线,从此中国的抗日战争开始了全民族的抗战,成为抗日战争胜利的根本保证。
二、探究历史——不屈不挠地抗争
1、探究一:如何看待国民党正面战场和共产党敌后战场的抗战?
【新闻发布会:将班级分成两个大组分别代表国共双方】请分别代表国共双方阐述自己对抗战的贡献。
材料一:
正面战场:从1937年7月开始,国民党军队发动大型会战22次,重要战斗1117次,小型战斗28931次。陆军阵亡、负伤、失踪3211419人,空军阵亡4321人,毁机2468驾,海军舰艇损失殆尽。先后有70余名将军战死在沙场,其中佟麟阁、赵登禹、张自忠等8名上将;吴克仁中将(67军军长)冯安邦中将(42军军长)等32名中将;邹绍孟少将(124师参谋长)王凤山少将(暂45师师长)等32名少将。材料二:
敌后战场:中国共产党领导的人民抗日力量对敌作战12.5万次,消灭日、伪军171.4万人。同时,敌后抗日军民也付出了巨大的代价,部队伤亡60余万人,解放区人民群众伤亡600余万人。材料三:
以国民党军队为主体的正面战场,组织了一系列大仗,特别是全国抗战初期的淞沪、忻口、徐州、武汉等战役,给日军以沉重打击。
中国共产党领导的敌后战场,广泛发动群众,开展游击战争,八路军、新四军、华南游击队、东北抗日联军和其他人民抗日武装力量奋勇作战。平型关大捷打破了“日军不可战胜”的神话,百团大战振奋了全国军民争取抗战胜利的信心。敌后战场钳制和歼灭日军大量兵力,歼灭大部分伪军,逐渐成为中国人民抗日战争的主战场。
——胡锦涛《在纪念中国人民抗日战争暨世界反法西斯战争胜利60周年大会上的讲话》
学生发言后小结:
国民党正面战场:(1)抗战:卢沟桥抗战、淞沪会战、太原会战、徐州会战、武汉会战(播放有关影象资料);中国远征军远征缅甸。(2)评价:积极抗日,粉碎了日军速决战的计划;节节败退(片面抗战路线)。(先在课件上打出证明国民政府在抗战时期抗战的有关数据,让学生总结概括国民政府抗战的评价。最后打出胡锦涛主席《在纪念抗日战争胜利60周年大会上的讲话》中对国民党抗战的评价加深学生印象。)
共产党敌后战场:全面抗战路线;建立敌后根据地;重大战役:平型关战役(抗战初期第一次胜利)、百团大战(主动出击的大规模战役)、回民支队的抗战。(课件展示有关中国共产党军队抗日的有关数据,表明中国共产党是抗日的中流砥柱。)
两大战场之间的关系:相互配合,相互支持。
2、探究三:抗日战争胜利的原因。
【谜语大家猜】抗日战争胜利的原因(打一历史人物)。(屈原、苏武、共工)(1)抗日民族统一战线建立,全民族抗战(根本原因);(2)中共领导的人民军队起了中流砥柱作用;(3)国民党爱国官兵的英勇抗战;
(4)国际反法西斯联盟的有力支持和配合(苏联的援助、美国的原子弹);(5)日本发动的是侵略的、非正义的法西斯战争。
3、探究四:抗日战争的胜利在中国反抗外来侵略斗争中的历史地位。(课件:展示相关材料,学生阅读后发言)。材料一:
在如何看待中国战场问题上,美国总统罗斯福曾说:“如果中国屈服,……那将是日军和纳粹的大规模钳形攻势,在近东某处会合,完全切断俄国同外界的联系,瓜分埃及,切断经过地中海的所有交通线……” 材料二:
在反法西斯战争中,中国伤亡3500万人,死亡2000多万人,直接经济损失620亿美元,间接经济损失5000亿美元;美国死亡40.5万人;英国死亡37.5万人。
学生发言后总结:
(1)第一次反帝斗争完全胜利;
(2)增强民族自尊、自信心,为革命胜利奠定基础;
(3)对世界反法西斯战争胜利作出重大贡献;
(4)中国的国际地位得到提高。
三、感悟历史——让历史告诉未来
60多年过去了,日本帝国主义发动的那场罪恶的侵华战争到底给中日两国带来了什么?中日两国的人们对待战争的态度又如何?
课件:展示日本首相小泉参拜靖国神社图片、西德总理勃兰特在波兰下跪图片
(图片配文字:同样是祭拜,相似的事件,不同的形式,迥异的内容。德国人跪下了,跪在了受难者墓前,跪得是那么的坦诚;日本人却站着,站在了凶手的牌位下,站得是那么的孤傲。同样举起过屠刀,也同样放下了凶器。德国人正视历史、尊重历史,用真诚换取理解,融入欧洲,强大自身;日本人无视历史、歪曲历史,用丑恶掩盖罪恶,一意孤行,伤害四邻。有的人下跪了,他显得更崇高;有的人还站着,他看着更卑微;有的人为尊严,有的人为生存;有的人毫无廉耻,有的人荒诞不经……下跪,意味着什么?你又为什么而下跪?参拜,又意味着什么,惨死在日本屠刀下的中国人,什么时候才能听到同样的忏悔?)
日本政要参拜靖国神社是日本不愿正视历史,日本军国主义复活的表现之一。你还知道哪些表现?(日本篡改教科书、否认南京大屠杀等)
中国:赵薇日本军旗装图片(我不懂这段历史)
侵华日军细菌战中国受害诉讼原告团团长兼总代表、2002年十大人物之一的王选图片
(颁奖词:“她用柔弱的肩头担负起历史的使命,她用正义的利剑戳穿弥天的谎言,她用坚毅和执著还原历史的真相。她奔走在一条看不见尽头的诉讼之路上,和她相伴的是一群满身历史创伤的老人。她不仅仅是在为日本细菌战中的中国受害者讨还公道,更是为整个人类赖以生存的大规则寻求支撑的力量,告诉世界该如何面对伤害,面对耻辱,面对谎言,面对罪恶,为人类如何继承和延续历史提供了注解。”)
(只要有两个王选这样的女人,就可以让日本沉没。——美国历史学家谢尔顿·h·哈里斯。下一个“王选”,会是你吗?)
【课堂感悟】通过本节课的学习,你从中得到哪些感悟? 我们应该怎么做?
(历史不能忘却,忘记历史就意味着背叛!防止日本军国主义复活;以史为鉴,面向未来。好好学习,报效国家)
课后探究(两题任选一题): 1、2005年,香港人大代表朱幼麟向全国人大递交了《我国国家级、国际化纪念抗战胜利60周年》的议案。请你就抗日战争设计一项国家级、国际化的纪念活动(包括活动形式、设计理念及设计理由等)。
2、阅读下列材料:
法国一位名叫切尔西的女记者对日本广岛和中国的南京两个灾难深重的城市纪念活动进行了记录,现摘抄一些:
广岛:被原子弹轰炸的残骸都保存完好;
南京:难以找到当年屠城遗址。
广岛:2001年,公布原子弹受害者221893人,精确到个位。
南京:大屠杀死难人数34万以上,纪念馆“哭墙”上只刻有3000个死者的名字;
广岛:每年8月6日,举行悼念大会,8月15日,钟声汽笛鸣响,工厂、学校、机关停止一切工作,全城哀悼;
南京:大屠杀纪念大会从1985年才开始,1997年才有了拉响防空警报和车船汽笛的做法,除了悼念大会会场,鲜见肃立默哀场面。
广岛:参加纪念大会人数有5万多人,占全市人口的1/21。
南京:参加纪念大会人数2000人左右,最多不到一万人,占全市人口的1/2800或1/500……
第五篇:高中化学人教必修一1.1.2-蒸馏和萃取--教案
人教必修1
教案
蒸馏和萃取1.1.2
一、教材分析:蒸馏和萃取是在实际生产生活中有着广泛应用的分离和提纯技术,海水淡化问题是目前解决全球淡水日益紧缺问题的重要途径,这为选修《化学与技术》奠定了一定的知识基础。萃取对于学生来说是全新的分离和提纯技术,它是对溶解性规律的一个应用,其原理也在今后卤族元素和有机物的学习中多次体现,在生活中也有多方面 的应用。本节课教学内容主要包括两个方面:
(一)复习蒸馏的原理,掌握实验室规范的蒸馏装置。这部分内容只作复习和简单的扩充;
(二)介绍萃取的原理和装置,特别是实验操作中的细节。这部分知识为新知识,应采用灵活多样的教学手段由浅入深地让学生理解和掌握。蒸馏和萃取是高中阶段的两个基本实验操作,学生对于相关内容及部分仪器还比较陌生,本节课的主要目的就是让学生了解蒸馏和萃取的操作及过程,学习一些仪器的使用方法,并进
一步丰富分离提纯物质的方法和手段。
二、教学目标
(一)知识与能力 .认识化学实验在学习和研究化学中的作用。1.知道液体混合物分离和提纯的常用方法——蒸馏和萃取,能根据物质的性质设计分离和提纯方案,并初步掌握2
其操作技能。体验科学探究的过程,通过亲自实验和教师指导,让学生掌握做好实验的方法。
(二)过程与方法: 能发现生产、生活中有意义的化学问题,建立化学为生产、生活服务的观点。
(三)情感态度与价值观:
教学重点、难点
三、蒸馏和萃取的实验原理以及操作过程。教学重点:
蒸馏和萃取的掌握和应用。教学难点:
四、教学过程:【引言】上节课我们学习了粗盐的提纯,通过除杂质过滤的方法得到比较纯的盐水,大家想想如果我们要把盐水变
页6 共 页1 第
为淡水,该怎么做呢?比如说在海边,渔民们是怎么解决生活用水的问题;前段时间,中央电视台播放了郑和下西洋的那段历史,大
家知道他们是怎么解决长期在海上漂泊的吃水问题吗?
【展示】海水变淡水【引】做汤的时候,观察过锅盖吗?锅盖上有水珠,这水珠与汤不什么不同?为什么会有水珠?水蒸汽凝结?为什
么水蒸汽会凝结成水珠?我们在化学中应怎么称呼?那么这是一个什么过程,水蒸汽遇温度低的锅盖而凝成水珠附于锅盖。汤沸腾后,【讲】 大家想一想蒸馏是不是一种分离混合物的方法?如果是,那么是分离什么样的混合物?混合物的分离和提纯除了过滤、蒸发外,还有其他很多方法,这节课,我们来学习另外两种新方法:蒸馏和【过】 萃取)二(【板书】(distillation and extraction)蒸馏和萃取 【过】首先,让我们利用实验室通过蒸馏的方法除去自来水中的杂质制取蒸馏水的实验来学习蒸馏的过程、蒸馏1【板书】Cl使水中含有因为自来水厂使用了消毒剂氯对水进行了消毒。我们引用的自来水是纯净的水吗?不是。【引入】―。我们可以利用加入硝酸银溶液检验是否含有氯离子。
【实验演示】自来水中加入硝酸酸化的硝酸银溶液【讲】有明显白色沉淀生成,证明自来水中含有氯离子。那么,我们应该用什么方法除去自来水中的氯离子呢?能
否向上一堂课中使用化学方法,加入试剂反应除去?不能。加入试剂后会引入新的杂质,达不到我们实验目的。要想得到纯净水。可以使用加热将水变为水蒸汽,()然后再冷凝为纯净的液态蒸馏水。
【小结】实验室就是使用蒸馏的方法制取蒸馏水。
【投】原理:利用互溶的液体混合物中各组分的沸点不同,给液体混合物加热,使其中的某一组分变成蒸气再冷凝成(1)的水提纯其Fe3+(例如蒸馏含有液体,从而达到分离提纯的目的。蒸馏一般用于分离沸点相差较大的液体混合物。页6 共 页2 第
中水份,蒸馏石油提纯不同沸点的有机组分)、锥形瓶、胶管)仪器:铁架台、酒精灯、石棉网、蒸馏烧瓶、冷凝管、温度计、胶塞、牛角管(尾接管)2(【实验演示】实验室制取蒸馏水)蒸馏时的注意事项:3(【投】 防止爆沸。)碎瓷片(,烧瓶要垫上石棉网加热,烧瓶中还要加入沸石2/3烧瓶内液体的容积不超过a.温度计下端水银泡应置于烧瓶支管处,测量逸出气体的温度。b.冷凝水下口进,上口出。c.d.实验开始时,先开冷凝水,后加热。实验结束时,先停止加热,后关冷凝水。溶液不可蒸干。
【讲】锥形瓶中的液体就是蒸馏水,我们再用硝酸银溶液检验是否含有氯离子。
【实验演示】蒸馏水加入硝酸银溶液 实验室制取蒸馏水1-3 【投影小结实验】实验 现象 实验加硝酸银溶液有白色沉淀产生,滴入几滴稀硝酸和几滴硝酸在试管中加入少量自来水,、1
且沉淀不溶解 银溶液。℃100加热,烧瓶中水温升高到烧瓶中加入约100 mL、在2体积的自来水,再加入几1/3 沸腾,在锥形瓶中收集蒸馏水,如图连接好装置,向冷凝管中通入冷)或碎瓷片(粒沸石却水。加热烧瓶,弃去开始馏出的总分液体,用锥形瓶收 液体,停止加热10 mL 集约加硝酸银溶液于蒸馏水中,无沉然后滴入几滴稀硝酸取少量收集到的液体加入试管中,、3 共 页3 第 页6
淀 和几滴硝酸银溶液 【思考】、为什么冷却水通入方向与被冷凝蒸气流向相反?)为了使蒸馏出的蒸气与冷却水长时间充分接触,带走尽可能多的热量(、为什么温度计水银球的顶端要与圆底烧瓶支管下沿处于同一水平线?2对于蒸馏来说,只有精确控制蒸馏的温度才能达到分离提纯的目的,而蒸馏烧瓶支管口的温度正是被蒸馏变为气()体某组分的温度,故温度计水银球顶端要与圆底烧瓶支管下沿处于同一水平线、在日常生活中,我们应用蒸馏的方法可以将海水淡化,或制造无水酒精。若采用蒸馏的方法分离酒精和水的混)酒精沸点低,先蒸出的是酒精。(合物,先蒸馏出来的物质是什么?、从这个实验中,大家可以看出蒸馏适用于什么类型的混合物的分离?4
液态混合物中,沸点不同,除去难挥发或不挥发的物质。:)蒸馏的使用范围4(【投】加热是为了获得溶液的残留物时,要用蒸发;加热是为了收集蒸气的冷凝液体时,(【思考】蒸馏与蒸发的区别:)要用蒸馏【过渡】在日常生活中,有时我们的衣服粘了油渍,可以用汽油擦洗,这就是萃取的应用。接下来我们学习另外的 一种分离方法,叫做萃取与分液。、萃取2【板书】 【过】我们先来认识这个新的仪器:分液漏斗。【展示仪器】分液漏斗的组成,分液漏斗的活塞、盖子同漏斗本身是配套的。使用漏斗 前要检验漏斗是否漏水。方法为:关闭活塞,在漏斗中加少量水,盖好盖子,用右手压 住分液漏斗口部,左手握住活塞部分,把分液漏斗倒转过来用力振荡,看是否漏水定义:利用某溶质在互不相溶的溶剂中的溶解度不同,用一种溶剂把溶质从它(1)【投】
与另一种溶剂组成的溶液中提取出来,在利用分液的原理和方法将它们分离开来。【讲解+实验演示】我们通过实验来解释萃取的定义,我们知道碘单质在水中的溶解度 页6 共 页4 第
饱和碘水,倒入分液漏斗中。接着,按照萃取的定义,我们10ml不大,碘水呈黄棕色。碘是溶质,水是溶剂。取 要用另一种溶剂加把溶质碘从碘水中提取出来,这另外一种溶剂的选择要符合一些条件,)萃取剂的选择:2(【投】 溶质在萃取剂的溶解度要比在原溶剂(水)大。a.萃取剂与原溶剂(水)不互溶。b.萃取剂与溶液不发生发应。c.【讲解+实验演示】那么,我们根据这些条件可以选择了四氯化碳,由于碘在四氯化碳的溶解度比较大,所以我们就可以了,进行振荡。请大家注意振荡的操作:用右手压住分液漏斗口部,左手握住活塞部分,把分液漏4ml加入
(斗倒转过来用力振荡,注意放气怎么。振荡后将分液漏斗放在铁架台上静置。)强调放气的重要性【讲解】静置后,大家发现漏斗中的液体分为两层,下层为紫红色,这一层为碘的四氯化碳的溶液。上层溶液颜色
变淡了,证明碘水中的碘已经被萃取到四氯化碳中了,达到了碘和水分离的目的,这就是萃取。)。。。勺子舀,吸管吸,(【引导】大家想想,萃取后,如何分离?比如汤上面的油层是怎样弄走的?【讲】我们试想一下,可不可以想办法使汤使下面流走,让油刚好留在容器中。容器下面有通道,汤从下面流走,在汤刚好流完时,关闭通道,这样汤和油不就分开了吗,这正好符合分液漏斗的结构。、分液3【板书】,为什么?【讲解+实验演示】最后一步,就是把四氯化碳层和水层分开,这就是分液。首先,打开盖子(塞子)(平衡大气压)将活塞打开,使下层液体慢慢流出。漏斗下端口靠烧杯壁。上层液体从上口倒出,为什么?(防止
上层液体混带有下层液体)【投影总结】
定义:把两种互不相溶的液体(且密度不同)分开的操作(1)【板书】萃取与分液的步骤: 检验分液漏斗是否漏水a.加入溶液,加入萃取剂,振荡b.页6 共 页5 第
静置分层c.分液d.(四个步骤)以及掌握萃取与分液的操作步骤。,(三个条件)大家要掌握的是萃取剂的选择通过这个实验,【小结】
附:板书设计:、蒸馏、萃取和分液
(二)、蒸馏1、萃取2、分液3 萃取与分液的步骤:4.分液 d.静置分层 c.加入溶液,加入萃取剂,振荡 b.检验分液漏斗是否漏水a.五、教学反思本节学习了混合物的分离和提纯的基本操作:蒸馏、分液和萃取,在实验室上这节课充分的调动了学生学习的兴趣和积极性,虽然准备实验很麻烦,但提高了课堂效率,不用再另找时间做实验。学生分组实验并合作探究,在老师的引导下完成教学重点内容——蒸馏、分液和萃取的基本操作,并通过亲身实践进一步领会了蒸馏、分液和萃取法,突破了本节课的难点——蒸馏、分液和萃取的基本操作原理和注意事项,在探究实验的过程中学生也提升了,还有许多分离和提纯的方法,化学学的科学素养。在化学实验和科学研究中利用物质的,等等。此外,如分馏、层析整堂课学生求知旺我们将在今后的学习中慢慢接触到。,应用也十分广泛,特殊性质来分离和检验物质的方法也很多
盛,复杂的知识变得简单化,亲自动手操作,加深了印象,提高了能力。页6 共 页6 第