第一篇:八下Unit 6全英教案
Unit 6 How long have you been collecting shells?
Period 1 Section A I.Teaching aims and teaching demands:
In this unit students learn to talk about how long you have been doing things.II.Teaching key and difficult points:
A.Vocabulary
collect, inline, marathon, skate, stamp, shell, globe, monster,particularly, run out of, be interested in,last year, times, numbers, How long…? birthday, penguin, hobby, kite B.Target language How long have you been skating? I’ve been skating since nine o’clock.When did you start skating? I started skating at nine o’clock.Students are skating at the Hilltop School.C.Structures Present perfect progressive Simple past tense Present progressive tense III.Teaching methods: Audio-lingual methods IV.Teaching aids: a tape recorder V.This unit is divided into eight periods.Period2 Section B I.Teaching aims and demands : Students practice using the target language.II.Teaching key and difficult points:
A.Vocabulary stamp, collect stamps, kites, B.Target language ①What does he collect? He collects kites.②How long have you been collecting these kites? Since I was ten years old.③How many do you have?
I have about 35.④I collect shells because they are beautiful.⑤I’d like to collect stamps because they are interesting.Step 1 Grammar Focus
Go through grammar focus with the students together.Step 2 Reading(3a.)Task 1.Read the passage.Task 2.Explain some difficulties by the teacher.① talk to sb.② raise money
③ the first one to
④ an hour ago ⑤ How long have you been playing Task 3.Find the sentences of the Present Perfect Progressive Tense by students.Step3 Group work
Finish 3b and 4.Step 4.Pairwork 2b This activity reviews and introduces selected vocabulary.Task 1.Ask a student to read the sample answers and then fill in the chart and tell your partner what you collect and what you would like to collect, say why.Task 2.First read the conversation in the box, then ask students to work in pairs to talk about their answers.Task 3.Have some pairs act their conversations to the class.Step 5.Listening 2a This activity gives students practice writing the target language and understand it in spoken conversation.Task 1.Read the instructions.Say you will hear three conversations.They are about Bob, Marcia , and Liam and their collections.First of all, let’s look at some key words.so far 到目前為止
stuffed animals 填充玩具動(dòng)物
an interesting collection 一個(gè)有趣的收藏 theater and movie tickets 電影票
Task 2.Play the recording the first time.Students only listen.Task 3.Play the recording a second time.Ask the students to fill in the table.Then correct the answers.Step 6.Listening 2b Listen carefully.Then check the answers.Step 7 lead in Look at the four pictures and answer the following questions.1.What can you see in the pictures? 2.What are they? Step 8 Reading(3a)1.Read the passage by students and draw lions connecting each snow globe and its description.2.Explain some difficulties by the teacher.3.Find the sentences of The Present Perfect Progressive Tense.Step9Writing(3b)
1.First ask students to complete the message according to Activity 2a.2.Check their answers.3.Show a sample message on screen by a projector and ask students to read by themselves.Step 6 Group work(4a)
Make a survey about everyone’s hobby.Find out how long they have been doing their hobby.Task 3.Teach these words:
1.因?yàn)樽瞿呈露兄x某人:thanks /thank sb for doing sth.=give/return thanks to sb for doing sth 2.因?yàn)槟呈露兄x某人:thanks/thank sb for sth=thanks to sb for sth 3.事實(shí)上:in fact=as a matter of fact 4.我最喜愛(ài)的(人、物):my favorite 5.不得不(客觀因素):have to do sth I had to work for a boss in order to make a living.(為了生存,我不得不為老板工作)
6.一定、必須(主觀因素):must do sth I must work hard.(我必須努力工作)7.用完:run out of 無(wú)意碰到,跑過(guò):run across 追趕:run after 逃跑:run away 自來(lái)水:running water 8.使某事由別人做/遭受了……、:have sth/sb+過(guò)去分詞
I'm going to have my shoes mended tomorrow.(明天我去補(bǔ)鞋子)She had her hands burned.(她燒傷了她的手)①使某人做某事:have/let/make sb do sth ②使……處于……、狀態(tài):have sb/sth doing sth ③have a good time/a lesson/a meeting/a rest/a talk/a swim.....④穿著 :have on ⑤和某人講話:have a word with ⑥最好:had better do sth 9.北極熊:polar bears 10.別人:anyone else=anybody else 別的一些事情:something else 別的任何事情:everything else 沒(méi)有別的事情:nothing else 別的什么事情:what else 11.在某人……歲生日:on one's +序數(shù)詞 birthday
on my seventh birthday(在我7歲生日的時(shí)候)12.到處:be all around
13.帶有動(dòng)物的玻璃器:globes with animals 14.讓?zhuān)ㄊ梗┠橙俗瞿呈拢簂et/make/have sb do sth 有這種用法的還有一些感官動(dòng)詞:
see sb do sth
hear sb do sth
notice sb do sth
feel sb do sth
watch sb do sth
如果接-ing形式,則表示動(dòng)作正在進(jìn)行。15.順便說(shuō)一句:by the way 16.在去……、的路上:on the way(to)....17.擋路:in the way 18.用這種(那種):in this(that)way 19.在某種程度上:in a way 20.決不:in no way 21.迷路:lose one's way 22.喜歡做某事:like to do sth/like doing sth 23.大約兩年:about two years 24.告訴關(guān)于……、:tell about...25.制作一個(gè)……的清單:make a list of....26.完成做某事:finish doing sth 27.對(duì)……感興趣:be/become interested in....28.每?jī)赡辏篹very two years.29.把某物送給某人:send sth to sb=send sb sth 30.停止做某事:stop doing sth 31.停下來(lái)做某事:stop to do sth Step 6.Writing
Task 1.Read the instructions.Task 2.Ask the students to write the e-mails on their own.Task 3.Ask some students to read their e-mails to the class.Step 7Homework 1.Review the vocabulary.2.Write your own conversations about your collections.Period3 Reading and writing I.Teaching aims and demands : Students practice the target language by reading and writing.II.Teaching key and difficult points: A.Vocabulary
the capital of,a city with a very colorful history,in Russian style,more than,be welcomed by,Chinese history,be far from,be certain B.Target language
① This is an teresting city with a very colorful history.② Since I came to China, I’ve been learning a lot about my family history.③ I think if you study hard, you’ll be able to understand any culture III.Teaching methods: Audio-lingual methods and Control-writing.IV.Teaching aids: a tape recorder V.Teaching procedure Step1 Dictation Step 2 Selfcheck(Part 1)1.Get students to fill in the blanks and then check their answers.2.Make their own sentences with the words.Step 3 Self check(Part 2)1.Get students to read the ad.2.Ask students to finish the letter on the own.3.Check their answers and five some explain.Step 4 Reading: I’ve been studying history in China.Section 1 Before you Read:
Ask students to answer the following questions: ① How mush so you know about history? ② How many Chinese dynasties can you think of? ③ How many famous characters from Chinese history can you think of?(make a list)④ Can you think of famous characters from the history of other countries Step 5 Section 2 While You Read: Reading strategy
Let students scan the text quickly to find details that they are looking for.Tell students they can find information quickly without reading the whole text Step 6 Section 3 After You Read:
Ask students to go through the reading again.Then have them complete the sentences below.1.Leo has been teaching in China for_______.2.Some buildings in Harbin are______.3.The _______ welcomed the first Jewish settlers to China.4.In Australia, students usually study _______ and ______ history.5.The more Leo learns about ________, the more he enjoys ______ in China.Step 7 Group work(3b)1.Divide students into groups of three.2.Show the conversations in 3b on th3e screen.3.Ask students to practice the conversations, then let them make their own conversations according to3b.Step 8 Summary Key words: 1.the capital of …的省會(huì)/首都 2.with a very colorful history有著非常豐富的歷史 3.European influence 歐洲化影響 4.be in…style 具有……的風(fēng)格 are in Russian style俄羅斯風(fēng)格
5.So it was very interesting for me to learn that a lot of Jews came to live in Harbin many years ago.很多年前就有很多猶太人來(lái)到哈爾濱居住,這對(duì)我來(lái)說(shuō)了解這一歷史是非常有趣的。
6.In fact, the first Jews probably came to Kaifeng more than a thousand years ago, and were
welcomed by the Song Emperor.事實(shí)上, 最早的猶太人可能一千多年前就來(lái)到了開(kāi)封, 他們受到了宋朝皇帝的熱情歡迎。
7.It is + 形容詞+for sb to do sth 對(duì)于某人而言, 做某事很…… 如: 對(duì)你來(lái)說(shuō)完成此工作很容易。It’s easy for you to finish this work.對(duì)外國(guó)人來(lái)說(shuō)學(xué)中文有點(diǎn)難。
It’s a bit difficult for foreigners to learn Chinese.8.However, when I heard that I was going to work in China, I started studying Chinese history.然而, 當(dāng)我聽(tīng)說(shuō)我將在中國(guó)工作的時(shí)候,我開(kāi)始學(xué)習(xí)中國(guó)歷史。I’ve been studying for over two years now.我已經(jīng)學(xué)習(xí)兩年了。(現(xiàn)在完成進(jìn)行時(shí))9 9.For a foreigner like me, the more I learn about Chinese history, the more I enjoy living in China.對(duì)于一個(gè)象我這樣的外國(guó)人來(lái)說(shuō), 了解中國(guó)歷史越多, 我越喜歡住在中國(guó)。10.the more I learn about Chinese history, the more I enjoy living in China.the +比較級(jí)……, the +比較級(jí)…… 越……越…… 你學(xué)習(xí)越認(rèn)真, 你的成績(jī)就會(huì)越好.
The harder you study, the better your grades will be.11.Although I live quite far from Beijing, I’m certain I will be here for the Olympic Games in 2008!quite adv.相當(dāng);十分
quite far from
距離……相當(dāng)遠(yuǎn) certain
adj.確實(shí)的;無(wú)疑的 be certain 確信……, 肯定…… =be sure the Olympic Games 奧林匹克運(yùn)動(dòng)會(huì)
12.自便。You ______ _____ to come and go as you please.13.If you know where she is,please________(告之我)14.We have_______(用盡)money to buy the house.15.Tom _______(對(duì)……感興趣)science ten years ago.16.He would like to ______(交些朋友)in China.17.The poor man had to________(謀生)by begging.
第二篇:新目標(biāo)八下unit3全英教案
為您提供初中英語(yǔ)教學(xué)資源
Unit 3: What were you doing when the UFO arrived?
I.Analysis of the Teaching Material 1.Teaching Aims and Demands(1)Knowledge Objects: In this unit students learn to talk about past events and to tell a story.(2)Ability Objects: To train the students’ ability of listening, speaking, reading and writing.(3)Moral Objects: To be virtuous is to do good.Virtue is fairer than beauty.2.Teaching Key Points: Introducing the key vocabulary and target language.3.Teaching Difficulties: New language ? I was standing in front of the library when the UFO landed.While the alien was buying a key ring, I called the police.? UFO, alien, took off, landed, arrived, bathroom, bedroom, kitchen, barber's chair, barber shop, standing, studying, cleaning, talking, cutting, cooking, eating, getting out, bought, got out, making, sleeping, buying, while, when II.Teaching Time: Six periods Section AAdditional materials to bring to class
? paints or markers and large paper for a class mural Language goal ? Ask one student to leave the room and wait outside the door.Then ask different students to start doing different things.One student can walk around the room.Another can look out of the window.A third can stand on his or her chair.Ask all three students to continue doing what they are doing without stopping and then ask the student outside the door to come in.? Ask the student outside the door to come in and sit down.Then ask the three students who were walking around the room, looking out the window, and standing on a chair to sit down.? Ask the first student who was doing an action, What were you doing when(student A)walked in? Help him or her to answer(supplying the whole answer if necessary), / was walking around the room when(student A)walked in.Ask die class to repeat, He(She)was walking around the room when(student A)walked in.? Repeat this with the second and third students who were doing actions: / was looking out the window when(student A)walked in.Ask the class to repeat, He(She)was looking out the window when(student A)walked in.The third student says, 1 was standing on a chair when(student A)walked in.Ask the class to repeat, He(She)was standing on a chair when(student A)walked in.? Ask some other students the question.What were you doing when(student A)walked in? They may answer.-/ was sitting here when(Student A)walked in or/ was talking to Carlos when(Student A)walked in.1 a This activity introduces some key vocabulary.? Point to the sentences.Say each sentence to the class and ask the students to repeat it-Ask-students to explain what each one means.They can use actions and simple explanations.For example, for in the bathroom, a student can pretend to he brushing his or her teeth or taking a shower and say, 1 was in the bathroom.I was brushing my teeth or I was in the bathroom.I was taking a shower.For barber shop and barber's chair, you may want to draw simple pictures on the
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hoard showing two barber chairs in a barber shop with a barber cutting a boy's hair.? Point out the six people and read the letter next to each one.Then ask students to write the letter of each person in the write-on line in front of each sentence.? Point out the sample answer.? Correct the answers.b This activity gives students practice in understanding the target language in spoken conversation.? Read the instructions.? Point to the people in the picture in activity la.Say, You will hear a recording of a reporter talking to the people in this picture.? Point to the two phrases after each letter in this activity.Say, There are two phrases after each letter.Listen carefully and circle the phrase that tells what each person was doing.Point out the sample answer.? Play the recording the first time.Students only listen
? Point to the people in the picture as you hear about that person on the recording.? Play the recording a second time.This time ask students to circle the correct phrases.? Correct the answers.c This activity provides guided oral practice using the target language.? Read the instructions.? Point out the example in the sample dialogue.Ask two students to read it to the class.? Say, Now work with your partner.Start by reading the conversation in the box with your partner.The look at the other people in the picture and have conversations about these people.You can use words and phrases from activity 1b.? As they talk, move around the room checking their work.Offer language support as needed.? Ask several pairs of students to say their conversations to the class.2a This activity gives students practice in understanding the target language in spoken conversation.? Read the instructions.? Point to the sentences with write-on lines.Say, You will hear a recording of a reporter talking to several people.Please put a number I in front of the thing that happened first, a number 2 in front of the thing that happened second, and so forth.? Play the recording the first time.Students only listen.Point to the sentences.? Play the recording a second time.This time ask students to write the numbers in front of the correct phrases.? Correct the answers.2b This activity provides listening and writing practice using the target language.? Read the instructions.Point to the write-on lines in each sentence.? Play the recording.Ask students to write the word when or while on each line.? Play the recording again.Ask students to correct their answers.Grammar note Point out that the abbreviation UFO means Unidentified Flying Object—something that is flying through the air that is unknown(unidentified)here on earth.Say Many abbreviations using two or three letters have a period after each letter For example, N.Y means New York and M.D.means Medical Doctor.But some abbreviations do not use periods.We usually write the abbreviation UPO without periods.2c This activity provides guided oral practice using the target language.? Point out the picture.Ask students to say what each person is doing.? Read the instructions.Then point 10 the example in the sample dialogue-Ask three students to
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read it to the class.Say, Make conversations like this about the people in the picture.? Ask students to work in small groups.Move around the room checking the progress of the groups and offering help as needed.? Ask a group to say its conversation to the class.Grammar focus ? Review the grammar box.Ask students to say the two forms of each statement.? Repeat the activities from the Language Goal section at the beginning of this unit using different students and different actions.For example, have a different student wait outside the door.Have three students in the classroom read a book, sit on the floor, and draw a picture on the board.? Ask the student outside the door to come in and sit down.Then ask the three students who were reading a hook, sitting on the floor, and drawing a picture to sit in their chairs.? Ask the first student who was doing an action, What were you doing when(student A)walked in? Guide him or her to answer, 1 was reading a book when(student A)walked in.Ask the class to repeat.He(She)was reading a book when(student A)walked in.? Repeat this with the second and third students who were doing actions.? Draw a long horizontal line across the board.Write the words / was drawing a picture on the line.Then make a star in the middle of the line and write the word's when(student A)walked in below the star.Point to the straight line and say This action continued for a long time.Then point to the star and say, This action happened quickly.Run your finger along the line as you say the words, I was drawing a picture.Then slap your hand on the board at the star as you say the words, when(student A)walked in.? Point out that the word when comes before a quick action that happens only once.The word while comes before an action that continues for some time.? Ask students to say other sentences with when and while from this unit(or from their own lives).Optional activity Describe an action that you did earlier in the day and that took only a moment to do and tell what time it happened.For example,/ ate and listened to the news at 7:00 this miming, Then ask students to tell what they were doing at that time using the words when and while.Help the students make the first few students make sentences like these: / was sleeping when he/she listened to the news.or When he/she was listening to the radio, I was eating breakfast.Then describe similar actions at different times and ask students to make sentences using when and while.3a This activity provides reading and grammar practice using the target language.? Read the instructions.? Look at the pictures with the students.Ask them to describe what is happening in each one.? Ask students to complete the work on their own.? Correct the answers.3b This activity presents an opportunity for students to measure their vocabulary production against their comprehension.Students may understand what they read, but it is also important that they be able to tell others what they understand.? Read the instructions.? Ask one or two students to epxiain what is happening in one of the pictures.為您提供初中英語(yǔ)教學(xué)資源
Encourage them with additional vocabulary they may have forgotten.? Ask students to complete the work in pairs.Remind them to use as many details as possible in their stories.Students may also add new details.? Ask a few students to tell their stories to the class.Encourage students to add details.4
This activity encourages students to use times to discuss their own experiences.? Read the instructions.? Ask two students to read the sample dialogue.? Ask another one or two students to talk about what they did at different times.You may use times and days other than the ones listed in the exercise.? Ask students to complete the work in groups.Students list and discuss their different activities.? Ask a few students to share their lists.Ask a few students to talk about their day in a conversation.Homework: Review Section A.Recite the words in this unit.Preview Section B.Finish Exx.Section A.Section B New language ? shouted, shouting, took a photo, scared, police officer, call the police, newspaper reporter, climbed, climbing, jump down, couldn't, another, station, crowded, found, happened, ran away 1 This activity introduces some key vocabulary.? Point to the pictures and ask students to say what they see.Provide key vocabulary words as needed.Repeat incomplete or incorrect sentences in full,correct form.[T = Teacher, S = student] T: What is the cat doing? Sl: Going up the tree.T: That's correct.The cat is climbing the tree.It's climbing the tree.Class repeat.It's climbing the tree.SS: It's climbing the tree.? Read the instructions, say, Write the letter of each picture in front of the correct sentence.? Point out the sample answer.Ask students to finish the work on their own.? Correct the answers.2a This activity gives students practice in understanding the target language in spoken conversation.? Read the instructions.? Point to the phrases in the chart.Say, You will hear a recording of two people talking.They will talk about some of these things.They will not talk about two of these things.Check the things they talk about.Point out the sample answer.? Play the recording the first time.Students only listen.? Play the recording a second time.This time ask students to check the phrases they hear on the recording.? Correct the answers.2b This activity gives students practice in understanding the target language in spoken conversation.? Read the instructions.Say, This time you will be listening only for who did each thing.? Point to the third column in activity 2a.Point out the sample answer.Ask students what that answer means(It means that item 1 in activity la [saw a cat in a tree] matches with item e in activity 2a []ohn1.)Say, John saw a cat in a tree.為您提供初中英語(yǔ)教學(xué)資源
? Play the recording.Ask students to write the correct fetter after the actions they checked in activity 2a.? Play the recording a second time, if necessary.? Correct the answers.2c This activity provides guided oral practice using the target language.? Read the instructions.Say, One student will start the sentence and the other student will finish it.? Point to the example in the sample dialogue.Ask two students to read it to the class.? Ask students to work in pairs.Move around the room checking progress and offering help as needed.? Ask several pairs to say some of their sentences to the class.Optional activity
Some students may be ready to do a more advanced form of this activity.Ask these pairs of students to make up true sentences about their lives starting with the word while.For example, they can talk about what they were doing yesterday afternoon.One might say, While I was walking home yesterday afternoon...The other could say, While I was walking home yesterday afternoon, I saw a big dog.3 This activity provides reading and writing practice using the target language.? Read the instructions, pointing to the article and the list of questions.? Ask students to say what they see in the picture.Accept any reasonable answers.Rephrase any incomplete answers or answers with incorrect language as complete.correct sentences.For example: T: what do you see in the picture?S1: Suitcase.T: That's correct.There's a suitcase in the picture.What else is in the picture?S2: A woman.T: Correct.There's a woman.Where is she?S3: Train station? T: Yes, there's a woman at a train station.? Ask students to read the article to themselves, circling any words or phrases they don't understand.Explain these words or phrases or ask other students to do this.? Read the article to the class.Answer any other questions students may have.? Point to the list of five questions.Ask students to write tile answers.? Correct the answers.4a This activity presents an opportunity for students to engage in open-ended writing.? Read the instructions.? Ask one or two students to explain what is happening in one of the pictures.Be careful not to ask for too many descriptions or the other students will not have to think about their answers.? Ask students to complete the work on their own.Remind them to use times in their stories.? Ask a few students to read their stories.Ask if some students have different stories.If not, suggest different endings.For example, The girl's brother found her bike and thought she had forgotten it there.4b This activity lets students practice their speaking an listening skills in role plays.? Read the instructions.Students work in pairs with two students at a time playing the role of police officer and bicycle thief.? Ask students to complete the work on their own.? Ask a few students to show their role plays to the class.Ask the students to vote on the best role play.Homework: Review this unit.Finish Exx.Section B.Recite 3a Writing: Predicting your future, including your future job, the city you will live, etc.Preview the next unit.
第三篇:浙教版 八下 教案 全
學(xué)智教育
浙 教 版 教 案
(八年級(jí)下)
第一章:粒子的模型與符號(hào) 第1節(jié)
模型、符號(hào)的建立與作用
教學(xué)目標(biāo)
1、體驗(yàn)使用符號(hào)、建立模型的思想。
2、能用物質(zhì)粒子模型來(lái)解釋物質(zhì)的三態(tài)變化。重點(diǎn)難點(diǎn)分析 體驗(yàn)使用符號(hào)與建立模型的思想
課程資源的準(zhǔn)備與開(kāi)發(fā) 地球儀、PPT圖片、細(xì)胞模型 教 學(xué) 預(yù) 設(shè) 調(diào) 控 對(duì) 策
【引入】回憶以前學(xué)習(xí)中,曾用用過(guò)的符號(hào)(略)。【討論】為什么要使用這些符號(hào)?用這些符號(hào)來(lái)表示實(shí)物? 【板書(shū)】
一、符號(hào)
用符號(hào)能簡(jiǎn)單明了地表示事物,可避免由于事物外形不同和表達(dá)地文字語(yǔ)言不同而引起地混亂。
【引語(yǔ)】除了符號(hào),我們還使用模型,請(qǐng)舉例。
如地球儀、細(xì)胞模式圖、眼球模型等。【討論】為什么要使用這些模型呢?
學(xué)智教育
1、因?yàn)榈厍蛱螅y以認(rèn)識(shí),所以人們常用地球儀。
因?yàn)榧?xì)胞太小,難以觀察,所以人們畫(huà)出了細(xì)胞模式圖。
由于眼球構(gòu)造太復(fù)雜,難以表達(dá),人們制造了眼球模型。
2、讀圖:
液態(tài)水與氣態(tài)水的狀態(tài)模型 通過(guò)讀圖,可知:
一、水在三態(tài)變化中,分子沒(méi)有發(fā)生變化;
二、水在三態(tài)變化中,分子間的距離發(fā)生了變化。
3、建立模型的意義:
可以幫助人們認(rèn)識(shí)和理解一些不能直接觀察到的事物。
4、模型的不同表示方法: 【練習(xí)】
【補(bǔ)充】元素符號(hào)的記憶和書(shū)寫(xiě)。【馬龍老師備課】
【引入】在我們已經(jīng)學(xué)完的三冊(cè)科學(xué)書(shū)里,我們接觸了很多新的東西。例如:
運(yùn)動(dòng)學(xué):v
t
s
電學(xué):R
I
U
單位:m/s
s
m
單位:Ω
A
V 請(qǐng)同學(xué)用一個(gè)次來(lái)概括一下以上的內(nèi)容,可見(jiàn)這些都是一些符號(hào) 【新授】
一、請(qǐng)同學(xué)說(shuō)出日常生活中常見(jiàn)的符號(hào)
二、請(qǐng)同學(xué)門(mén)討論為什么要使用這些符號(hào)?
講解:例如時(shí)間,不同國(guó)家用不同的文字表示,為了減少這種語(yǔ)言文化帶來(lái)的差異,我們就用T來(lái)表示時(shí)間,再如一些復(fù)雜的事物,如電路圖中的元件,如果都要用實(shí)物表示,那么電路圖會(huì)變的十分復(fù)雜,所以我們就用一些簡(jiǎn)單的符號(hào)表示,可見(jiàn) 符號(hào)的作用:
1、簡(jiǎn)單的表明事物
2、避免混亂
學(xué)智教育
三、模型
1、請(qǐng)同學(xué)描述一下對(duì)地球的認(rèn)識(shí)
2、請(qǐng)同學(xué)在地球儀上找到一些相應(yīng)的位子,并描述一下。
3、同學(xué)們都知道,任何生都是由細(xì)胞構(gòu)成的,請(qǐng)同學(xué)說(shuō)一下動(dòng)物細(xì)胞和植物細(xì)胞的區(qū)別。
畫(huà)出細(xì)胞模式圖
再請(qǐng)一位同學(xué)根據(jù)細(xì)胞模式圖來(lái)分析一下動(dòng)物細(xì)胞和植物細(xì)胞的區(qū)別。
4、眼球的結(jié)構(gòu)很復(fù)雜,所以我們通常用人們制造的眼球模型來(lái)認(rèn)識(shí)其結(jié)構(gòu)
5、請(qǐng)同學(xué)們填寫(xiě)書(shū)本第二頁(yè)的填空
地球儀、細(xì)胞模式圖、眼球模型就是用模型來(lái)表示一些我們通過(guò)肉眼直接很難觀察很難認(rèn)識(shí)清楚的對(duì)象時(shí)采用的方法,所以從某種意義上講符號(hào)也是一種模型。
四、請(qǐng)問(wèn)同學(xué)水有幾種狀態(tài)?
水用符號(hào)表示為“H2O”也就是說(shuō)它由兩個(gè)氫原子,一個(gè)氧原子構(gòu)成,用模型表示水分子
從三態(tài)說(shuō)明三種模型(略)
請(qǐng)同學(xué)在書(shū)上填空
通過(guò)模型,我們可以直觀的區(qū)分出水的三態(tài),從模型中我們也可以知道水在三態(tài)中,分子沒(méi)有發(fā)生變化,變化的是分子間的距離,需要強(qiáng)調(diào)一點(diǎn),一個(gè)模型可以是一張圖,一個(gè)物體,也可以是對(duì)一個(gè)復(fù)雜的對(duì)象或過(guò)程的 示意,如光合作用,我們將光合作用過(guò)程中物質(zhì)的變化概括的寫(xiě)成一個(gè)簡(jiǎn)單的表達(dá)式就是一個(gè)模型,包括我們以后要學(xué)的化學(xué)方程式都是模型。五,綜述
通過(guò)學(xué)習(xí)同學(xué)們應(yīng)該建立一種使用符號(hào)和模型的思想,它可以幫我們形象的認(rèn)識(shí)事物的共同點(diǎn),免去一些外因的科學(xué)研究是一個(gè)由具體到抽象,再由抽象到具體的過(guò)程符號(hào)和模型就是中間的紐帶,所以我們建立了模型和符號(hào)的概念對(duì)我們以后學(xué)習(xí)科學(xué),研究科學(xué)是很有利的,同學(xué)們通過(guò)學(xué)習(xí)后經(jīng)常去使用一些符號(hào)和模型,也可以去設(shè)計(jì)一些符號(hào)和模型,只要方便使用就可以。當(dāng)然你設(shè)計(jì)的符號(hào)如果沒(méi)有經(jīng)過(guò)有關(guān)機(jī)構(gòu)的認(rèn)同,千萬(wàn)不要公開(kāi)發(fā)表!包括你的作業(yè)和試卷。
學(xué)智教育
第2節(jié)
物質(zhì)與微觀粒子模型
教學(xué)目標(biāo)
1、知道物質(zhì)是由分子構(gòu)成的,分子是由原子構(gòu)成,物質(zhì)也可由原子直接構(gòu)成。
2、知道原子組成分子時(shí)結(jié)構(gòu)和種類(lèi)不同,物質(zhì)的性質(zhì)也不同。
3、認(rèn)識(shí)分子微粒的大小、質(zhì)量的數(shù)量級(jí)。重點(diǎn)難點(diǎn)分析 重點(diǎn):知道物質(zhì)的不同構(gòu)成:分子、原子和離子。
知道物質(zhì)構(gòu)成與性質(zhì)的關(guān)系。難點(diǎn):認(rèn)識(shí)微粒的數(shù)量級(jí)的大小。
課程資源的準(zhǔn)備與開(kāi)發(fā) 用橡皮泥和牙簽讓學(xué)生制作分子模型 實(shí)驗(yàn):稱(chēng)量米的質(zhì)量 教 學(xué) 預(yù) 設(shè) 調(diào)控對(duì)策
【復(fù)習(xí)】你對(duì)分子的了解有多少?
--物質(zhì)由分子構(gòu)成;分子在不停地運(yùn)動(dòng);分子間有間隙;
【引入】分子又是由什么粒子構(gòu)成的呢?
【分析】水電解實(shí)驗(yàn):說(shuō)明水是由氫、氧元素組成; 水分子是由更小的粒子構(gòu)成的--原子構(gòu)成。由這個(gè)實(shí)驗(yàn)還可以知道:
1、分子和原子的區(qū)別:在化學(xué)變化中,分子可分,原子不可再分。
2、化學(xué)變化的實(shí)質(zhì):分子分割成原子,原子重新組合成新的原子。
3、化學(xué)變化和物理變化的本質(zhì)區(qū)別:在變化中,物質(zhì)的分子變成了其它物質(zhì)的分子,就是化學(xué)變化。在變化中,物質(zhì)的分子還是原來(lái)的分子,只是分子間的距離發(fā)生了變化,就是物理變化。
學(xué)智教育
【介紹】人類(lèi)對(duì)原子的認(rèn)識(shí)歷程。(資料打印)
【讀圖】我們用模型來(lái)認(rèn)識(shí)分子、原子,表示化學(xué)反應(yīng)過(guò)程。【結(jié)論】
一、物質(zhì)--分子--原子
宏觀--微觀----物質(zhì)組成的層次性 【了解】不同的物質(zhì)由不同的微粒構(gòu)成。
金屬由原子構(gòu)成;石墨由碳原子組成;
--說(shuō)明哪些物質(zhì)是由原子直接構(gòu)成的:金屬和固體非金屬
二、不同種類(lèi)的物質(zhì)
【讀圖】【思考】不同物質(zhì)的模型
(1)構(gòu)成分子的原子可以是同種原子,也可以是不同種原子。
(2)同種原子構(gòu)成不同物質(zhì)時(shí)結(jié)構(gòu)是不一樣的。--金剛石中碳原子的排列成網(wǎng)狀,石墨中碳原子的排列成層狀,足球烯中碳原子的排列成球狀。重點(diǎn)講解:金剛石和石墨在性質(zhì)上的區(qū)別: 物理性質(zhì)上:硬度、導(dǎo)電性、熔點(diǎn)、沸點(diǎn)等;
化學(xué)性質(zhì)上:一樣。【舉例】科學(xué)家做過(guò)的實(shí)驗(yàn):在密閉的容器中充滿氧氣,分別放入金剛石和石墨,結(jié)構(gòu)都生成唯一的產(chǎn)物--二氧化碳。
三、粒子的大小與質(zhì)量
1、分子和原子都有一定的質(zhì)量和體積.原子的體積很小,半徑的數(shù)量級(jí)在10-10米。原子的質(zhì)量也非常小,數(shù)量級(jí)在10-26千克。
2、不同質(zhì)量的原子質(zhì)量不同,體積也不同。【認(rèn)識(shí)】不同的分子和原子質(zhì)量。
【學(xué)生活動(dòng)】感受10-27千克質(zhì)量大小。稱(chēng)量1克米,數(shù)出米的粒數(shù)。【補(bǔ)充】
學(xué)智教育
第3節(jié)
原子結(jié)構(gòu)的模型
教學(xué)目標(biāo)
1、了解原子的構(gòu)成、原子結(jié)構(gòu)模型及其在歷史上的發(fā)展過(guò)程,體驗(yàn)建立模型的思想。
2、了解同位素的結(jié)構(gòu)特點(diǎn),能說(shuō)出1-2項(xiàng)在實(shí)際生活中的用途
3、知道物質(zhì)也可由離子構(gòu)成,認(rèn)識(shí)離子微粒大小的數(shù)量級(jí)。重點(diǎn)難點(diǎn)分析 重點(diǎn):了解原子的構(gòu)成、原子結(jié)構(gòu)模型及其在歷史上的發(fā)展過(guò)程,體驗(yàn)建立模型的思想。難點(diǎn):對(duì)原子結(jié)構(gòu)知識(shí)的初步了解 課程資源的準(zhǔn)備與開(kāi)發(fā) 實(shí)驗(yàn),課外資料
調(diào)控對(duì)策 教 學(xué) 預(yù) 設(shè)
【作業(yè)講評(píng)】:摩擦起電的原因:物體中本來(lái)就存在正電荷和負(fù)電荷,通常情況下正負(fù)電荷的數(shù)量相等,物體是中性的。當(dāng)兩個(gè)物體摩擦?xí)r,電子從束縛較弱的物體轉(zhuǎn)移到另一物體。失去電子的物體帶正電,得到電子的物體帶負(fù)。注意:摩擦起電都是帶負(fù)電的電子轉(zhuǎn)移,而不是帶正電的正離子或質(zhì)子等的轉(zhuǎn)移。【引入】
1、練習(xí):由同種原子構(gòu)成的物質(zhì)是純凈物;
由不同種原子構(gòu)成的物質(zhì)是混合物;
分子是由不同種原子構(gòu)成的。
2、復(fù)習(xí):物質(zhì)的構(gòu)成、電流的形成 【新授】
一、原子結(jié)構(gòu)模型的建立與修正
1、道爾頓--實(shí)心球原子結(jié)構(gòu) --發(fā)現(xiàn)原子
學(xué)智教育
2、湯姆森--“湯姆森模型”:原子是一個(gè)平均分布著正電荷的球體,帶負(fù)電荷的電子嵌在中間。
--發(fā)現(xiàn)電子
3、盧瑟福--“盧瑟福模型”:電子繞原子核運(yùn)行 【介紹】實(shí)驗(yàn):α粒子轟擊原子
4、波爾--“分層模型”:電子在固定的軌道上運(yùn)動(dòng)
5、“電子云模型”--電子在核周?chē)械膮^(qū)域出現(xiàn)的次數(shù)多,有的區(qū)域出現(xiàn)的次數(shù)少,就象“云霧”一樣籠罩在核的周?chē)?/p>
【小結(jié)】建立模型是一個(gè)不斷完善、不斷修正的過(guò)程。使學(xué)生體驗(yàn)、學(xué)習(xí)科學(xué)家提出問(wèn)題、建立假設(shè)、修正模型的研究方法。
二、原子的結(jié)構(gòu):
1、原子:
原子核:
帶正電(不顯電性)
核外電子:帶負(fù)電
2、原子核大小與核外電子運(yùn)動(dòng)范圍(原子大小)的比較。
三、揭開(kāi)原子核的秘密
1、原子核是由更小的兩種粒子質(zhì)子和中子構(gòu)成的。
核電荷數(shù):原子核所帶的電荷數(shù)
一個(gè)電子帶一個(gè)單位的負(fù)電荷,一個(gè)質(zhì)子帶一個(gè)單位的負(fù)電荷;
【讀表】思考:在原子中哪些數(shù)目總是相等的?(1)核電荷數(shù)=質(zhì)子數(shù)=核外電子數(shù)。(2)中子數(shù)不一定等于質(zhì)子數(shù)。(3)原子內(nèi)可以沒(méi)有中子。
2、質(zhì)子、中子核電子的質(zhì)量比較
質(zhì)子、中子的質(zhì)量大小幾乎相等。電子質(zhì)量很小,在整個(gè)原子的質(zhì)量中所占的比例極小,可忽略不計(jì)。所以說(shuō),原子的質(zhì)量主要集中在原子核上。
學(xué)智教育
【讀圖】一杯水的微觀層次分析
3、一杯水--水分子--氧原子、氫原子--原子核、核外電子--質(zhì)子、中子--夸克
四、原子的“孿生兄弟”--同位素
1、具有相同的核電荷數(shù)(即質(zhì)子數(shù))的同一類(lèi)原子的總稱(chēng)為元素。如:氧元素就是所有氧原子的總稱(chēng)。
同種原子的原子核內(nèi)核電荷數(shù)、質(zhì)子數(shù)與中子數(shù)是一定的。但有的原子其核內(nèi)的中子數(shù)會(huì)發(fā)生變化。
【舉例】氧的三種原子的原子核:核內(nèi)都有8個(gè)質(zhì)子,但中子數(shù)分別是8個(gè)、9個(gè)、10個(gè)。屬于同種元素的不同原子。
2、原子中原子核內(nèi)質(zhì)子數(shù)相同、中子數(shù)不相同的同類(lèi)原子統(tǒng)稱(chēng)為同位素。氧的同位素原子是氧元素的不同種原子。
【思考】氧的3種同位素其核外電子應(yīng)各有幾個(gè)?--8個(gè)。如:氫有3種同位素原子:氕、氘、氚。汞有7種同位素。
3、同位素元素在工業(yè)、農(nóng)業(yè)、醫(yī)療、國(guó)防等方面有廣泛的應(yīng)用:化學(xué)分析、消除細(xì)菌、醫(yī)學(xué)診斷等。
【閱讀】利用碳-14同位素測(cè)定年代
五、帶電的原子--離子 【實(shí)驗(yàn)】鈉在氯氣中燃燒的實(shí)驗(yàn)
實(shí)驗(yàn)現(xiàn)象:
鈉原子失去電子--形成正電荷的鈉離子(陽(yáng)離子)氯原子得到電子--形成負(fù)電荷的氯離子(陰離子)
所以,離子就是帶電的原子或原子團(tuán)(離子的組成元素不止一種)。離子和分子、原子一樣也是構(gòu)成物質(zhì)的基本粒子。【學(xué)生實(shí)驗(yàn)】估計(jì)高錳酸鉀離子的大小 說(shuō)明:這是一個(gè)思想實(shí)驗(yàn)。
學(xué)智教育
目的:讓顯示感受到離子的存在,利用簡(jiǎn)易可行的實(shí)驗(yàn)估計(jì)構(gòu)成物質(zhì)的粒子--離子大小的數(shù)量級(jí)。
基本操作技能:固體藥品的取用;毫米刻度尺的使用;液體體積的測(cè)量;振蕩。主要科學(xué)方法:估計(jì)方法、觀察實(shí)驗(yàn)方法、對(duì)比方法。
實(shí)驗(yàn)設(shè)計(jì)思路:已知經(jīng)過(guò)多次按1/10稀釋后,最后能看到的紫紅色高錳酸鉀溶液中,每100毫升大約存在1000個(gè)高錳酸鉀離子。根據(jù)稀釋的次數(shù)克推算出高錳酸鉀晶體中含有的高錳酸鉀離子數(shù)為N。溶解前,先用毫米刻度尺測(cè)量并估算出離子的大小,這是一種通過(guò)宏觀現(xiàn)象推測(cè)微觀世界的思想方法。
學(xué)智教育
第4節(jié)
組成物質(zhì)的元素
教學(xué)目標(biāo)
1、知道自然界的物質(zhì)由100多種元素組成,從組成物質(zhì)元素角度出發(fā)理解物質(zhì)初步分類(lèi)思想。
2、知道組成人體、地球的主要元素。重點(diǎn)難點(diǎn)分析 重點(diǎn):?jiǎn)钨|(zhì)和化合物的概念 難點(diǎn):區(qū)別單質(zhì)、化合物、混合物 課程資源的準(zhǔn)備與開(kāi)發(fā)
教 學(xué) 預(yù) 設(shè) 調(diào) 控 對(duì) 策
【引入】講人類(lèi)認(rèn)識(shí)微觀世界的歷史 【新授】
一、元素的種類(lèi) 1、110多種,包括人造元素。
元素分類(lèi):金屬元素和非金屬元素(包括稀有氣體元素:在自然界含量極少,性質(zhì)非常穩(wěn)定)
2、單質(zhì):由同種元素組成的純凈物。舉例:氧氣、金屬鐵等。化合物:由不同種元素組成的純凈物。舉例:二氧化碳、水等。【注意】單質(zhì)和化合物的區(qū)別及分類(lèi)依據(jù)
【閱讀】元素名稱(chēng)的由來(lái):進(jìn)一步來(lái)了解元素的分類(lèi)
二、元素的分布
1、元素在地殼的分布是不均勻的,地殼主要由氧、硅、鋁、鐵、鈣、鈉、鉀、鎂、氫等元素組成。其中含量最高的是氧,其次是硅。金屬元素中含量最高的是鋁,其次是鐵。
2、在人體中含量最高的是氧元素,其次是碳、氫; 【閱讀】人體種元素的作用
【校本課程】營(yíng)養(yǎng)與各元素的攝取;廣告與生活
3、在海水中除了水由氫氧兩種元素組成以外,含量較高的是氯元素和鈉元素(氧85.5%,氫10.7%,氯2.0%,鈉、鎂等1.5%),還有貴重的金屬等--海洋是資源寶庫(kù),21世紀(jì)是“海洋
學(xué)智教育 的世紀(jì))。
【課外探究】海水中氕、氘、氚的利用
4、生物所含的大量的有機(jī)化合物如血糖、植物纖維主要由碳、氫和氧三種元素組成的。
5、人造元素通過(guò)核反應(yīng)制得的,其中一部分人造元素核天然元素具有放射性。有利有弊:對(duì)人體有害;利用放射性可以治療一些疾病。
第5節(jié)
表示元素的符號(hào)
教學(xué)目標(biāo)
日 期
1、認(rèn)識(shí)常見(jiàn)元素符號(hào)(H、0、C、S、Si、Na、Fe、Cu、Cl、Ca、Ag、Al、I、K、P),學(xué)智教育
會(huì)查閱元素符號(hào)。
2、通過(guò)探究活動(dòng),初步認(rèn)識(shí)元素周期表,知道金屬元素和非金屬元素在元素周期表中的分布。
3、閱讀元素周期表的發(fā)現(xiàn)及應(yīng)用的地形、典型歷史事實(shí),體會(huì)科學(xué)家的創(chuàng)造性思維和元素周期表的重要意義。
重點(diǎn)難點(diǎn)分析 重點(diǎn):認(rèn)識(shí)常見(jiàn)元素符號(hào)
難點(diǎn):元素周期表的認(rèn)識(shí)和簡(jiǎn)單運(yùn)用
課程資源的準(zhǔn)備與開(kāi)發(fā)
教 學(xué) 預(yù) 設(shè) 調(diào) 控 對(duì) 策
【復(fù)習(xí)】元素的種類(lèi)、分布以及與物質(zhì)、原子、分子間的關(guān)系 【新授】
一、元素符號(hào)
1、元素符號(hào)是國(guó)際上統(tǒng)一采用的符號(hào),通常用該元素拉丁文的第一個(gè)大寫(xiě)字母來(lái)表示。當(dāng)元素的第一個(gè)字母與其它元素重復(fù)時(shí),克寫(xiě)上該元素名稱(chēng)的第二個(gè)字母以示區(qū)別。
2、元素符號(hào)一般表示: ⑴一種元素
⑵這種元素的1個(gè)原子 ⑶這種元素的原子的質(zhì)量
【練習(xí)】“2N”等的意義;與“N2”的區(qū)別
二、元素周期表
【介紹】簡(jiǎn)單介紹元素周期表
7個(gè)周期(短周期、長(zhǎng)周期、不完全周期); 16個(gè)族(7個(gè)主族、7個(gè)副族、0族、第8族); 112種元素(金屬元素、非金屬元素、稀有元素); 【探究】尋找元素周期表中元素之間的聯(lián)系和規(guī)律
1、提出問(wèn)題:
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2、建立假設(shè):規(guī)律可能表現(xiàn)在元素的性質(zhì)上; 規(guī)律可能表現(xiàn)在元素的種類(lèi)上; 規(guī)律可能表現(xiàn)在元素的質(zhì)量上; 規(guī)律可能表現(xiàn)在元素的質(zhì)子數(shù)上; 規(guī)律可能表現(xiàn)在元素的中子數(shù)上; 規(guī)律可能表現(xiàn)在元素的發(fā)現(xiàn)史上;
3、設(shè)計(jì)方案:研究課本上的元素周期表
4、記錄考察結(jié)構(gòu)
5、驗(yàn)證假設(shè)
6、交流 【小結(jié)】
第6節(jié)
表示物質(zhì)的符號(hào)
教學(xué)目標(biāo)
1、會(huì)查元素的化合價(jià),會(huì)運(yùn)用化合價(jià)寫(xiě)出簡(jiǎn)單的化學(xué)式。
2、能解釋化學(xué)式表示的意義,能根據(jù)化學(xué)式區(qū)分單質(zhì)和化合價(jià)、金屬和非金屬。
3、能用;表示離子或帶電原子團(tuán)。
重點(diǎn)難點(diǎn)分析 重點(diǎn):會(huì)查元素的化合價(jià),會(huì)運(yùn)用化合價(jià)寫(xiě)出簡(jiǎn)單的化學(xué)式。難點(diǎn):會(huì)運(yùn)用
學(xué)智教育
化合價(jià)寫(xiě)出簡(jiǎn)單的化學(xué)式。課程資源的準(zhǔn)備與開(kāi)發(fā)
教 學(xué) 預(yù) 設(shè) 【復(fù)習(xí)】
1、默寫(xiě)元素符號(hào)
2、說(shuō)明符號(hào)的意義 【新授】
一、化學(xué)式
1、用元素符號(hào)來(lái)表示物質(zhì)分子組成的式子稱(chēng)化學(xué)式
2、化學(xué)式的確定依據(jù):由實(shí)驗(yàn)測(cè)定組成,如水的電解實(shí)驗(yàn)測(cè)定水的組成。不能憑空想象,一種物質(zhì)只有一種化學(xué)式。
3、化學(xué)式的書(shū)寫(xiě)原則 ⑴單質(zhì)化學(xué)式的寫(xiě)法: 雙原子分子: 稀有氣體: 多原子分子:
固態(tài)非金屬(結(jié)構(gòu)復(fù)雜,習(xí)慣上用元素符號(hào)表示): 金屬(同上):
⑵化合物化學(xué)式的寫(xiě)法:按一定順序?qū)懗鼋M成化合物的所有元素符號(hào),然后在每種元素符號(hào)的右下角用數(shù)字寫(xiě)出化合物分子中該元素的原子個(gè)數(shù)。
一定順序:氧元素與另一種元素組成的化合物,一般要把氧元素符號(hào)寫(xiě)在左邊;氫元素與另一元素組成的化合物,一般要把氫元素寫(xiě)在左邊;金屬元素、氫元素與非金屬元素組成的化合物,一般要把非金屬元素寫(xiě)在右邊。
直接由離子構(gòu)成的化合物,其化學(xué)式常用其離子的最簡(jiǎn)單整數(shù)比表示。【例】 【練習(xí)】 調(diào) 控 對(duì) 策
學(xué)智教育
4、化學(xué)式的讀法:一般從右向左讀做“某化某”;或者要指出一個(gè)分子里的個(gè)數(shù)。
5、化學(xué)式表示的意義: ⑴表示某種物質(zhì)(純凈物)⑵表示某種物質(zhì)的一個(gè)分子 ⑶表示物質(zhì)的元素組成 ⑷表示物質(zhì)分子的構(gòu)成 ⑸表示分子的質(zhì)量 【例】 【練習(xí)】 【補(bǔ)充】
1.化學(xué)式能代表某種質(zhì),如CO2這個(gè)化學(xué)式就代表二氧化碳。因?yàn)橐环N物質(zhì)只用一個(gè)化學(xué)式來(lái)表示。
2.化學(xué)式能表示物質(zhì)組成。如H2O這個(gè)化學(xué)式能表示出水是由氫元素和氧元素組成。
3.化學(xué)式能表示物質(zhì)中原子或離子個(gè)數(shù)比。如NaCl這個(gè)化學(xué)式表示在氯化鈉中氯離子和鈉離子的個(gè)數(shù)比為1∶1。
4.通過(guò)化學(xué)式可計(jì)算式量。如水的化學(xué)式是H2O,H2O的式量=1×2+16=18
5.通過(guò)化學(xué)式可計(jì)算組成物質(zhì)的各元素的質(zhì)量比。如二氧化硫中硫元素和氧元素的質(zhì)量比等于:32:16×2=1∶1
6.通過(guò)化學(xué)式可計(jì)算物質(zhì)中某一元素的質(zhì)量分?jǐn)?shù)。
二、離子的符號(hào)
【引入】當(dāng)原子失去或得到電子成為離子時(shí),怎樣用符號(hào)來(lái)表示呢?
1、離子符號(hào)是在形成該離子的原子的元素符號(hào)右上角標(biāo)出該離子所帶的電荷數(shù)。
2、離子符號(hào)的意義:
3、常見(jiàn)的離子(包括原子團(tuán)所帶的電荷數(shù))
三、化合價(jià)
1、原子之間相互化合的數(shù)目,用化合價(jià)來(lái)表示。
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2、常見(jiàn)化合價(jià):
金屬元素、非金屬元素,氫、氧元素的化合價(jià)規(guī)律; 常見(jiàn)原子團(tuán)(根)的化合價(jià)。
3、原則:在化合物中所有元素化合價(jià)的代數(shù)和為零。
4、單質(zhì)的化合價(jià)為零。
5、標(biāo)價(jià)方式與離子表示方式。
6、應(yīng)用:
根據(jù)化合價(jià)的代數(shù)和為零推出各元素的化合價(jià); 根據(jù)化合價(jià)寫(xiě)出化合物的化學(xué)式。【例】
第7節(jié) 元素符號(hào)表示的量
教學(xué)目標(biāo)
1、會(huì)查閱相對(duì)原子質(zhì)量表。
2、能根據(jù)化學(xué)式計(jì)算物質(zhì)的相對(duì)分子質(zhì)量。
3、能根據(jù)化學(xué)式計(jì)算元素含量、所含元素質(zhì)量比。
重點(diǎn)難點(diǎn)分析 重點(diǎn):能解釋化學(xué)式表示的意義;相對(duì)原子質(zhì)量的了解及查閱;根據(jù)化學(xué)式計(jì)算相對(duì)原子質(zhì)量和元素的質(zhì)量比。
難點(diǎn):根據(jù)化學(xué)式計(jì)算相對(duì)原子質(zhì)量和元素的質(zhì)量比。課程資源的準(zhǔn)備與開(kāi)發(fā) PPT課件
學(xué)智教育
教 學(xué) 預(yù) 設(shè) 【引入】
今天我們要來(lái)學(xué)習(xí)元素符號(hào)表示的量,首先請(qǐng)同學(xué)們回憶一下“C”表示的意思
表示碳元素
C
表示一個(gè)碳原子
表示碳元素的質(zhì)量
關(guān)于前面兩層意思我們已經(jīng)進(jìn)行了詳細(xì)的分析和討論,今天我們就來(lái)研究一下其中的第三層含義 【新授】
我們知道“C”這個(gè)元素符號(hào)可以表示一個(gè)碳原子的質(zhì)量,且由相關(guān)的表中可以查得
C:1.993×10-26千克
H: 1.674×10-27千克
O: 2.657×10-26千克
由此可見(jiàn),原子的質(zhì)量非常小,所以直接用它的真實(shí)質(zhì)量會(huì)使計(jì)算復(fù)雜,且數(shù)據(jù)不容易記憶,所以我們?nèi)∷麄兿鄬?duì)的值。在取這個(gè)相對(duì)的值之前我們必須先有一個(gè)標(biāo)準(zhǔn)。就像畫(huà)地圖時(shí)用的比例尺,我們就可以把一個(gè)國(guó)家按比例縮小畫(huà)到一張紙上,現(xiàn)在我們的原子質(zhì)量太小了,所以我們要讓它按比例擴(kuò)大,而且擴(kuò)大后的數(shù)值要盡可能易記,實(shí)際上這就是建立原子質(zhì)量模型。找出了原子質(zhì)量的標(biāo)準(zhǔn),我們就把其它原子的質(zhì)量與之相比,把比值就定義為某元素的相對(duì)原子質(zhì)量。下面就來(lái)規(guī)定這個(gè)標(biāo)準(zhǔn)
C-12(提問(wèn):12表示什么意思?表示質(zhì)子數(shù)和中子數(shù)之和是12,由于碳有兩種同位素,即C-12,C-14,所以必須指明是哪種碳原子。)C-12
M=1.993×10-26千克
1/12C-12
M=1/2×1.993×10-26千克=1.661×10-27千克 先留一個(gè)問(wèn)題,為什么要取1/12C-12作為標(biāo)準(zhǔn)?
找到了標(biāo)準(zhǔn),我們就可以給出任意一種元素的相對(duì)原子質(zhì)量了
學(xué)智教育
例如:O: 2.657×10-26千克/1.661×10-27千克
一、相對(duì)原子質(zhì)量
以C-12質(zhì)量的1/12作為標(biāo)準(zhǔn),其它原子的質(zhì)量跟它相比所得的比值,叫做這種原子的相對(duì)原子質(zhì)量。
【練習(xí)】查找各元素原子的相對(duì)原子質(zhì)量。
【閱讀】張青蓮教授與相對(duì)原子質(zhì)量--激發(fā)愛(ài)國(guó)熱情
二、相對(duì)分子質(zhì)量
1、一個(gè)分子中各原子的相對(duì)原子質(zhì)量總和就是該原子的相對(duì)分子質(zhì)量。【例題】注意規(guī)范及計(jì)算方法。H2SO4、3CO2、CUS04.5H2O等
2、化學(xué)式的意義:5點(diǎn)(1)表示一種物質(zhì);
(2)表示組成這種物質(zhì)的元素;(3)表示各種元素原子的個(gè)數(shù)比;
(4)表示這種物質(zhì)的一個(gè)分子(對(duì)由分子構(gòu)成的物質(zhì))。(5)表示物質(zhì)的相對(duì)分子質(zhì)量 【講解】及【練習(xí)】
三、元素質(zhì)量分?jǐn)?shù)和質(zhì)量比的確定
1、組成物質(zhì)的各種元素的質(zhì)量比 【例題】H2O、NH4NO3 【練習(xí)】Fe2O3、CO2、H2SO4、NH4HCO3、2、物質(zhì)中某一元素的質(zhì)量分?jǐn)?shù) 【例題】講解例題。
提醒學(xué)生注意:①各元素的質(zhì)量比跟原子個(gè)數(shù)比是不同的。例如NH4NO3中氮、氫、氧三種元素的質(zhì)量比是7∶1∶12,而它們的原子個(gè)數(shù)比是2∶4∶3。②計(jì)算NH4NO3中氮元素的質(zhì)量分?jǐn)?shù)時(shí),學(xué)智教育
【練習(xí)】
【補(bǔ)充】計(jì)算5t氧化鐵中含鐵多少?lài)崱解]氧化鐵的化學(xué)式是Fe2O3 氧化鐵的式量是56×2+16×3=160 5t氧化鐵中所含鐵的質(zhì)量是:5×70%=3.5(t)答:5t氧化鐵中含鐵3.5t。
復(fù)習(xí)教案
1、同種原子里
電量關(guān)系:核電荷數(shù)=質(zhì)子數(shù)=核外電子數(shù) 質(zhì)量關(guān)系:相對(duì)原子質(zhì)量數(shù)值=質(zhì)子數(shù)+中子數(shù) 2.同一種元素的離子里
電量關(guān)系:核電荷數(shù)=質(zhì)子數(shù)≠核外電子數(shù)
質(zhì)量關(guān)系:相對(duì)原子質(zhì)量數(shù)值=質(zhì)子數(shù)+中子數(shù) 3.同一種元素的原子、離子里
電量關(guān)系:核電荷數(shù)=質(zhì)子數(shù)>核外電子數(shù)
該微粒為陽(yáng)離子;
學(xué)智教育
核電荷數(shù)=質(zhì)子數(shù)<核外電子數(shù)
該微粒為陰離子; 核電荷數(shù)-核外電子數(shù)=陽(yáng)離子的正電荷數(shù)(元素正價(jià)數(shù))核外電子數(shù)-核電荷數(shù)=陰離子的負(fù)電荷數(shù)(元素負(fù)價(jià)數(shù))質(zhì)量關(guān)系:與原子、離子相同 4.相對(duì)原子質(zhì)量
元素的相對(duì)原子質(zhì)量=某元素一個(gè)原子質(zhì)量÷碳原子質(zhì)量的十二分之一。【例題講解】
例1:一種四價(jià)元素硫化物的式量與此元素氯化物的式量之比為100∶202,確定此元素的相對(duì)原子質(zhì)量和名稱(chēng)。
解:設(shè)此元素為M,則硫化物的化學(xué)式為MS2,氯化物化學(xué)式為MCl4,由已知條件知:MS2∶MCl4=100∶202
(M+64)∶(M+142)=100∶202(M+142)×100=(M+64)×202 M=12.47
答:此元素的相對(duì)原子質(zhì)量是12.47,是碳元素。
例2: x和y兩元素組成的A和B兩化合物,A的分子組成為xy2,其中x的質(zhì)量分?jǐn)?shù)為44.1%,B分子中x的質(zhì)量分?jǐn)?shù)為34.5%,B的化學(xué)式為
[
B
]
A.x2y
B.xy3
C.xy
D.x3y 例3:一包氯化銨(NH4Cl)化肥中,混入了少量某種其它化肥,此包氯化銨化肥中的含氮量為27.5%,則入的化肥可能是
(A)A、CO(NH2)2
B、(NH4)2SO4
C、NH4HCO3
D、KNO3 例
4、當(dāng)氨肥硝酸銨[NH4NO3]和尿素[CO(NH2)2]所含氮元素質(zhì)量相同時(shí),它們的質(zhì)量比是A、1∶1
B、8∶3
C、4∶3
D、2∶3
(C)例
5、R、X兩元素形成多種化合物在RX中R元素的質(zhì)量分?jǐn)?shù)為49.7%,則下列化合物中R元素質(zhì)量分?jǐn)?shù)大于43%的是
()
(A)RX
2(B)R2X
3(C)R2X
(D)R2X5 【練習(xí)】
1、已知n個(gè)銀原子的質(zhì)量為mkg,a個(gè)碳原子(測(cè)定相對(duì)原子質(zhì)量的一種碳原子)的質(zhì)量為bkg,則銀原子的相對(duì)原子質(zhì)量可表示為
[ A
]
學(xué)智教育
A.12am/bn
B.a(chǎn)m/12bn
C.12bn/am
D.bn/12am
2、已知K2MnO4的式量為m,若鉀的相對(duì)原子質(zhì)量為a,氧的相對(duì)原子質(zhì)量為b,則錳的相對(duì)原子質(zhì)量(表達(dá)式)為x=m-2a-4b。
3、某元素R的氧化物化學(xué)式為R2O3,若R與氧氣化合時(shí)的質(zhì)量比為9∶8,則R元素的相對(duì)原子質(zhì)量為
[ C
] A.9
B.13
C.27
D.56
4、某物質(zhì)的化學(xué)式是RH4,其中含氫25%,則R元素的相對(duì)原子質(zhì)量為_(kāi)_____。
5、由C2H6和C2H60組成的混合物中,氧元素的質(zhì)量分?jǐn)?shù)為A%,則碳元素的質(zhì)量分?jǐn)?shù)為。21
學(xué)智教育
第1節(jié)
大氣層
教學(xué)目標(biāo)
1、了解大氣層的重要性。
2、了解大氣溫度的垂直分布特點(diǎn)。
3、掌握大氣的垂直分布規(guī)律。
4、理解對(duì)流層的特點(diǎn),探究對(duì)流的形成。
重點(diǎn)難點(diǎn)分析
重點(diǎn):大氣的垂直分層規(guī)律
難點(diǎn):對(duì)流層的特點(diǎn);探究對(duì)流的形成教、學(xué) 預(yù) 設(shè)
一、大氣的重要性
地球周?chē)灰粚雍芎竦目諝獍鼑恢毖由斓?000千米的高空(主要集中在1000千米的高度)。包圍地球的空氣層叫大氣層,空氣也叫大氣。
【補(bǔ)充】大氣的成分:由氮?dú)狻⒀鯕狻⒍趸肌⑾∮袣怏w、臭氧、水蒸氣以及懸浮在其中的固體雜質(zhì)等物質(zhì)組成。
【討論】如果沒(méi)有大氣,地球會(huì)變得怎樣?
提示:地球?qū)⒆兊煤驮铝帘砻嬉粯樱瑳](méi)有天氣變化,沒(méi)有聲音,易受隕石的侵襲,溫度較差增大等。
大氣作用:
1、保護(hù)地球,如避免流星的襲擊
2、大氣中的各種氣體,都是人類(lèi)不可缺少的資源(舉例:氧氣進(jìn)行生命活動(dòng)必需的;二氧化碳是光合作用的重要原料)
3、臭氧層能保護(hù)地面上的生物免受太陽(yáng)紫外線的傷害
4、水蒸氣能成云致雨
二、大氣的溫度
【讀圖】大氣溫度的垂直分布圖
特點(diǎn):
1、大氣溫度的變化范圍約在-84℃--2500℃之間。
學(xué)智教育
2、在85千米以上,大氣的溫度呈逐漸上升趨勢(shì)(想一想為什么?太陽(yáng)輻射強(qiáng))。
3、在0-12千米、55-85千米之間氣溫隨高度的增加而降低
4、在12-55千米之間,氣溫隨著高度的增加溫度升高。【思考】哈勃望遠(yuǎn)鏡的外面為什么要穿一件銀白色的“外衣”?
——高層大氣溫度高、太陽(yáng)輻射強(qiáng),銀白色的金屬外殼可以反射熱的輻射,避免高溫下外殼熔化。
三、大氣的分層
根據(jù)大氣的溫度、密度和物質(zhì)組成等特點(diǎn)(大氣溫度在垂直方向上的變化是我們對(duì)大氣進(jìn)行分層的主要依據(jù)。),把地球大氣層分為五層,即對(duì)流層(0-17千米)平流層(17-50千米)中間層(50-80千米)暖層(80-500千米)
外層(500千米以上)外層就是地球大氣與宇宙間的過(guò)渡層。1000千米以上,大氣變得十分稀薄,密度很小。5000千米以外,大氣已接近真空。
四、對(duì)流層的特點(diǎn)
1、對(duì)流層是大氣的底層。
2、在兩極和赤道地地區(qū)的厚度不同。兩極厚度約8千米,在赤道增大到17-18千米。
3、對(duì)流層集中了地球四分之三的大氣質(zhì)量和幾乎全部的水汽、固體雜質(zhì)。
4、對(duì)流層最顯著的特點(diǎn)有強(qiáng)烈的對(duì)流運(yùn)動(dòng)。【探究實(shí)驗(yàn)】對(duì)流是怎樣形成的實(shí)驗(yàn)
1.燒杯中加高錳酸鉀或直接用對(duì)流實(shí)驗(yàn)裝置。2.
燃香的實(shí)驗(yàn)用實(shí)驗(yàn)室的現(xiàn)成器材,現(xiàn)象非常明顯。結(jié)論:受熱處空氣上升,兩側(cè)溫度低的地方空氣下沉。
【小結(jié)】想一想對(duì)流層的溫度特點(diǎn),對(duì)形成對(duì)流有利嗎?――它的溫度特點(diǎn)是氣溫隨高度的增加而降低,有利于對(duì)流的形成。
學(xué)智教育
所以,顯著的對(duì)流運(yùn)動(dòng)和充足的水汽,使對(duì)流層的天氣現(xiàn)象復(fù)雜多變,云、雨、雪、和雷電等主要的天氣現(xiàn)象都發(fā)生在這一層。對(duì)流層的各種天氣變化影響著生物的生存和行為,對(duì)流層是大氣層中與人們生活和生產(chǎn)關(guān)系最密切的一層。
【拓寬】冷空調(diào)應(yīng)該怎樣裝?冷藏室的冷凝管為什么要安裝在室的上部?――形成對(duì)流,達(dá)到制冷效果。
學(xué)智教育
第2節(jié)
天氣和氣溫
教學(xué)目標(biāo)
1、理解天氣的概念
2、知道什么是氣溫,以及測(cè)量和度量氣溫的常用儀器和方法。
3、學(xué)會(huì)測(cè)量氣溫
4、了解氣溫與人們的生活和其它生物的關(guān)系 重點(diǎn)難點(diǎn)分析
重點(diǎn):氣溫的觀測(cè)
難點(diǎn):探究為什么氣象觀測(cè)中溫度計(jì)要放在百葉箱里 教、學(xué) 預(yù) 設(shè) 一. 天氣是什么
短時(shí)間內(nèi)近地面的大氣溫度、濕度、氣壓等要素的綜合狀況稱(chēng)為天氣。刮風(fēng)、下雨、雷電等都是天氣現(xiàn)象。【讀圖】2-
6、2-7感受天氣
天氣是由許多要素組成的,其中主要的是氣溫、氣壓、風(fēng)、濕度和降水。【討論題】
1、判別描述天氣與氣候的詞語(yǔ)
2、說(shuō)說(shuō)當(dāng)天的天氣狀況
二、氣溫
1、氣溫的含義:空氣的溫度叫氣溫。描述當(dāng)?shù)乜諝獾睦錈岢潭取鉁厥菢?gòu)成天氣的基本要素。
2、測(cè)量氣溫的工具:溫度計(jì)
【分類(lèi)】水銀溫度計(jì)、酒精溫度計(jì)、金屬溫度計(jì)等;普通溫度計(jì)、最高溫度計(jì)、最低溫度計(jì) 【復(fù)習(xí)】溫度計(jì)的結(jié)構(gòu)和制造原理
3、氣溫度量單位:攝氏度(℃)【設(shè)問(wèn)】一般把溫度計(jì)放在一個(gè)漆成白色的百葉箱里,為什么? 【探究實(shí)驗(yàn)1】用溫度計(jì)分別測(cè)量百葉箱內(nèi)和百葉箱外的氣溫
學(xué)智教育
時(shí)間
上午
中午
下午
晚上
溫度(百葉箱內(nèi))溫度(百葉箱外)
據(jù)表中的數(shù)據(jù),進(jìn)行分析,得出實(shí)驗(yàn)結(jié)論: 1)百葉箱內(nèi)的氣溫比箱外低;
2)百葉箱內(nèi)的溫度波動(dòng)比較小,所以更能反映真實(shí)的氣溫。【探究實(shí)驗(yàn)2】探究一天中氣溫最高值和最低值大概出現(xiàn)在什么時(shí)間
實(shí)驗(yàn)結(jié)論:一般氣溫的最高值出現(xiàn)在午后2時(shí),氣溫的最低值出現(xiàn)在日出前后。【想一想】這是為什么?與太陽(yáng)輻射和大地散熱有關(guān)
4、氣溫與人類(lèi)生活和其它生物的關(guān)系――非常密切
【舉例】
1、人類(lèi)的生產(chǎn)方面:春播、夏收;冬季作物的防凍;農(nóng)作物有各自最適宜的生長(zhǎng)溫度;
2、人類(lèi)的生活方面:空調(diào)、暖氣;避暑療養(yǎng);
3、生物的行為:狗在高溫時(shí)的表現(xiàn);蛇的冬眠、蛙的產(chǎn)卵等。出示圖或?qū)嵨铮宰髦v解構(gòu)造與原理、用途等
引導(dǎo)學(xué)生在課外用連續(xù)觀測(cè)的方法得出結(jié)論,而且晴天的觀測(cè)效果比陰天好。軼事 記錄
最高溫度計(jì)和最低溫度計(jì)的制作原理是什么?這個(gè)問(wèn)題學(xué)生提了出來(lái),但是教師真的很難搞懂,何況學(xué)生。課后 反思
學(xué)智教育
限于學(xué)校的實(shí)驗(yàn)條件,氣溫的觀測(cè)只能放在課后或者是要求學(xué)生自主完成。探究實(shí)驗(yàn)的難度較大,學(xué)生盡管測(cè)出了溫度,但很難達(dá)到教學(xué)所要求的整理和比較能力。故而也難以得出結(jié)論。
如果能夠補(bǔ)充氣候的有關(guān)知識(shí),通過(guò)對(duì)比教學(xué),學(xué)生更易于掌握天氣的描述詞語(yǔ)
課內(nèi)探究實(shí)驗(yàn),兩人一組 軼事記錄
利用高錳酸鉀來(lái)演示對(duì)流實(shí)驗(yàn)(用對(duì)流管),現(xiàn)象清晰明了。學(xué)生頗感興趣,對(duì)于分析對(duì)流的成因非常易于接受。線香的實(shí)驗(yàn)也是在玻璃鐘罩內(nèi)進(jìn)行,效果很好。課后反思
通過(guò)實(shí)驗(yàn)來(lái)了解對(duì)流層的特點(diǎn),學(xué)生易于接受。補(bǔ)充大氣的作用,使學(xué)生對(duì)大氣與生活的關(guān)系更了解。對(duì)于飛機(jī)和衛(wèi)星在大氣中的分布學(xué)生很難理解。其實(shí),包括老師也能以理解。
學(xué)智教育
第3節(jié)
大氣的壓強(qiáng)教
教學(xué)目標(biāo)
1.能列舉證明大氣壓存在的實(shí)驗(yàn)現(xiàn)象,并能用大氣壓解釋有關(guān)現(xiàn)象。
2. 能說(shuō)出標(biāo)準(zhǔn)大氣壓的數(shù)值,說(shuō)出測(cè)量大氣壓的工具:水銀壓強(qiáng)計(jì)和空盒壓強(qiáng)計(jì)。3. 3.能說(shuō)出氣體和液體的流速與壓之間的關(guān)系:流速越大,壓強(qiáng)越小。并能用這一關(guān)系解釋有關(guān)現(xiàn)象。
重點(diǎn)難點(diǎn)分析 重點(diǎn):
1、氣壓的觀測(cè)
2、大氣壓存在的證明
3、氣體和液體的流速與壓強(qiáng)的關(guān)系 難點(diǎn):
1、大氣壓的大小
2、氣體和液體的流速與壓強(qiáng)的關(guān)系 教 學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
一、大氣壓的存在 【實(shí)驗(yàn)引入】
1、器材:一杯水(染成紅色),一個(gè)空杯,一個(gè)膠頭(或橡皮套),一根玻璃管(兩端開(kāi)口,粗細(xì)均勻,長(zhǎng)20cm,內(nèi)徑約5~10mm均可)
2、演示過(guò)程
1).出示玻璃管,將空杯置于管的正下方,然后向管內(nèi)倒水,可看到水從管底流出。2).左手拿管,并且用食指緊緊堵住玻璃管的下端,仍然向管內(nèi)注入水,至滿。3).教師提問(wèn):為什么水不會(huì)從下面流出?
學(xué)生微笑,齊答:因?yàn)楣艿妆皇种付伦×恕9P者肯定學(xué)生的回答,并指出:由于管底被手指堵住,所以手指對(duì)管內(nèi)的水產(chǎn)生向上的壓強(qiáng),支承住了水柱。接著置疑:若此時(shí)將管倒拿,使其開(kāi)口端朝下,水會(huì)不會(huì)流出?學(xué)生紛紛猜測(cè),形成懸念。
4).左手拿管不變,同時(shí)用右手中指抵住玻璃管的上口,然后將管倒置,(倒置過(guò)程中,手指不要松開(kāi))。
學(xué)智教育
5).接著故意緩慢移開(kāi)右手指,使下面的管口露出。這時(shí)可見(jiàn)紅色水柱并沒(méi)有流出來(lái)!
學(xué)生大吃一驚!教師自言自語(yǔ):咦,為什么水沒(méi)有流出來(lái)呢?(可用左手倒拿著管,夸張地放到眼底瞧一瞧)難道管里的水突然沒(méi)有了重力嗎?難道是老師會(huì)氣功,‘發(fā)功’將管內(nèi)的水吸住了嗎?
學(xué)生輕笑,同時(shí)產(chǎn)生了想獲知正確答案的強(qiáng)烈欲望。
6).啟發(fā):雖然我們看不見(jiàn)管口有物堵住它,但管口附近是不是任何物體都沒(méi)有呢? 學(xué)生茅塞頓開(kāi)――有空氣存在。因勢(shì)利導(dǎo):在管口四周存在著我們看不見(jiàn)的大量空氣,這些氣體起到了手指的作用,堵住了管口,使管內(nèi)的水竟然無(wú)可奈何地呆在里面。這說(shuō)明了這些大氣對(duì)管底的水面有向上的壓強(qiáng),支承著水柱。
7).這時(shí),仍有學(xué)生半信半疑,可進(jìn)一步說(shuō)明:因?yàn)楝F(xiàn)在管內(nèi)的水只有下面受到了大氣壓強(qiáng)的支承作用,所以很難流出;但如果同時(shí)有大氣作用在管的上水面,那么上、下作用的氣壓相互抵消,水就會(huì)在重力作用下流出來(lái)。
8).松開(kāi)左手食指,水應(yīng)聲落下。(學(xué)生開(kāi)始相信大氣有壓強(qiáng))
9).改用膠頭,套住玻璃管的一端,再做一遍,同樣獲得滿意效果。——大氣壓強(qiáng)確實(shí)存在.液體在各個(gè)方向上存在壓強(qiáng),氣體是否也一樣呢?
【學(xué)生實(shí)驗(yàn)】探究大氣壓強(qiáng)是否向各個(gè)方向都有.
①向上.玻璃杯裝滿水用紙片擋住,倒立玻璃杯,紙片不脫落,如圖1.說(shuō)明向上有大氣壓. ②向下.將剝了殼的熟雞蛋塞住剛燒過(guò)酒精棉球的廣口瓶口,很快雞蛋就被壓進(jìn)廣口瓶中.說(shuō)明向下有大氣壓.
③猜想向左、向往是否也有大氣壓,如何證實(shí)?(讓學(xué)生自己證實(shí))
通過(guò)上述演示實(shí)驗(yàn)及日常生活經(jīng)驗(yàn)得知——在氣體內(nèi)部向各個(gè)方向都有壓強(qiáng). 【解釋】圖2-
14、2-
15、2-16(學(xué)生動(dòng)手實(shí)驗(yàn)體會(huì)吸盤(pán)的作用)倘若沒(méi)有大氣壓強(qiáng)作用在液體的表面,各種液體就不可能被抽吸起來(lái)。從這個(gè)含義上講,一切抽吸液體的過(guò)程,其實(shí)都是大氣壓強(qiáng)將液體“壓”上來(lái)的過(guò)程.【演示實(shí)驗(yàn)】抽出可樂(lè)瓶中的氣體
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實(shí)驗(yàn)現(xiàn)象:可樂(lè)瓶變癟 實(shí)驗(yàn)結(jié)論:氣體向各個(gè)方向上都有壓強(qiáng)
【設(shè)問(wèn)】大氣壓確實(shí)是存在的,而且各個(gè)方向上都有壓強(qiáng)。那么大氣壓究竟有多大呢? 【演示】馬德堡半球?qū)嶒?yàn)
實(shí)驗(yàn)現(xiàn)象:兩個(gè)半球需用很大的力才能拉開(kāi) 提出疑問(wèn):是什么力使兩個(gè)半球合得那么攏?
討論后得出:是大氣的壓力把兩個(gè)半球緊緊壓在一起的,進(jìn)而讓學(xué)生確信大氣壓的存在.因?yàn)榈厍蛑車(chē)拇髿馐艿降厍虻奈创髿庖彩艿街亓Φ淖饔茫源髿鈱?duì)浸在其內(nèi)的物體就有壓力、壓強(qiáng)。如果半球內(nèi)為真空,那么要拉開(kāi)半球需要的力約為7065牛。――馬德堡半球?qū)嶒?yàn)證明了大氣壓的存在,而且說(shuō)明大氣壓是很大的。【閱讀】人體中的“馬德堡半球”
二、大氣壓的大小
大氣壓的大小跟我們的生活密切相關(guān),我們應(yīng)該知道大氣壓的測(cè)量方法。
1、大氣壓的大小可以用空盒氣壓計(jì)或水銀氣壓計(jì)進(jìn)行測(cè)量。
【出示】空盒壓強(qiáng)計(jì)(或叫金屬盒壓強(qiáng)計(jì)、無(wú)液壓強(qiáng)計(jì))觀察:其上有兩行刻度,一行以百帕為單位,一行以毫米汞柱為單位。說(shuō)明它的原理和構(gòu)造。【出示】水銀壓強(qiáng)計(jì)
補(bǔ)充實(shí)驗(yàn):托里拆利實(shí)驗(yàn)――進(jìn)行簡(jiǎn)單的實(shí)驗(yàn)說(shuō)明、數(shù)據(jù)讀數(shù)和分析,大氣壓支持著玻璃管中的水銀柱。當(dāng)大氣壓發(fā)生變化的時(shí)候,水銀柱的高度會(huì)發(fā)生變化。從中說(shuō)明水銀壓強(qiáng)計(jì)的原理。
【簡(jiǎn)單比較】:兩種壓強(qiáng)計(jì)的優(yōu)缺點(diǎn)
2、大氣壓的變化:
1)大氣壓的大小與大氣的密度有關(guān)--解釋?zhuān)捍髿鈮旱漠a(chǎn)生是由于大氣有重力。2)大氣壓的大小隨著高度的增加而減小--解釋?zhuān)捍髿獾拿芏入S著高度而減小。
實(shí)例:高山上氣壓很低。有些登山運(yùn)動(dòng)員在進(jìn)入高山地區(qū)后,會(huì)發(fā)生高山病。高山病的癥狀
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差別很大,包括:頭暈、頭痛、耳鳴、惡心、嘔吐、脈搏和呼吸加速、四肢麻木等。每個(gè)人的反應(yīng)隨一系列的條件而不同,主要決定于訓(xùn)練的程度和海拔高度的轉(zhuǎn)變速度等。登山運(yùn)動(dòng)員初次迅速攀登很高的山峰時(shí),會(huì)出現(xiàn)以下現(xiàn)象:睡眠不好,全身感覺(jué)不舒服,軟弱無(wú)力,懶散和情緒低落,動(dòng)作協(xié)調(diào)性差。呼吸系統(tǒng)的癥狀是:氣喘,時(shí)常感到空氣不足,睡眠時(shí)發(fā)生周期性的呼吸停頓,夜間感到窒息發(fā)悶。由于心臟血管系統(tǒng)機(jī)能狀況變化引起頭暈、鼻出血、耳鳴和血管跳動(dòng)的感覺(jué),皮膚和粘膜變得青紫或蒼白,常常惡心和嘔吐。嚴(yán)重的會(huì)陷入昏迷、甚至死亡。
高山病的主要原因是高山地區(qū)空氣稀薄,大氣壓低,人們呼吸時(shí)吸入的氧氣的分壓也低,造成肺泡中的氧分壓降低,血液中含氧量減少。
平原地區(qū)的青年人在高山地區(qū)居住一段時(shí)間后,對(duì)高山氣候的適應(yīng)能力和缺氧的抵抗能力都會(huì)提高。一般地說(shuō),高山病的急性癥狀就會(huì)逐漸減輕,以至消失。身體健康的人和訓(xùn)練有素的登山運(yùn)動(dòng)員對(duì)高山氣候的適應(yīng)能力也強(qiáng)。
3)在海平面附近,大氣壓的數(shù)值接近1.01×105帕(760毫米汞
柱)規(guī)定:這個(gè)大氣壓值稱(chēng)為標(biāo)準(zhǔn)大氣壓。
【討論】要求簡(jiǎn)單地運(yùn)用液體壓強(qiáng)公式進(jìn)行計(jì)算。并與磚的壓強(qiáng)進(jìn)行比較。【問(wèn)題】這么大的壓強(qiáng),我們?yōu)槭裁礇](méi)有受壓的感覺(jué)? --解釋?zhuān)喝藢?duì)環(huán)境的適應(yīng),人的體內(nèi)也有壓強(qiáng),它抗衡著體外的大氣壓。軼事記錄
本節(jié)課的引入很有意思,學(xué)生真的被深深地吸引。雖然這種現(xiàn)象在生活中出現(xiàn),但往往平時(shí)沒(méi)有注意。通過(guò)教師的渲染,學(xué)生更能體會(huì)到科學(xué)就在身邊。只不過(guò)是平時(shí)習(xí)以為常罷了。課后反思
本節(jié)內(nèi)容分3課時(shí)。第一課時(shí)主要為大氣壓的存在,補(bǔ)充一些實(shí)驗(yàn);第二課時(shí)主要講大氣壓的大小測(cè)定,補(bǔ)充托里拆利實(shí)驗(yàn)。第三課時(shí):流速與壓強(qiáng)的關(guān)系。具體見(jiàn)后面的教案。
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第3節(jié)
大氣的壓強(qiáng)(第3課時(shí))教學(xué)目標(biāo)
1、知識(shí)與技能:能說(shuō)出氣體和液體的流速與壓之間的關(guān)系:流速越大,壓強(qiáng)越小。并能用這一關(guān)系解釋有關(guān)現(xiàn)象
2、過(guò)程與方法:通過(guò)觀察與實(shí)驗(yàn),認(rèn)識(shí)氣體的壓強(qiáng)跟流速有關(guān)的現(xiàn)象。
3、情感、態(tài)度與價(jià)值觀:初步領(lǐng)略氣體壓強(qiáng)差異所產(chǎn)生現(xiàn)象的奧妙,獲得對(duì)科學(xué)的熱愛(ài)、親近感。
重點(diǎn)難點(diǎn)分析
重點(diǎn):氣體和液體的流速與壓強(qiáng)的關(guān)系
難點(diǎn):用氣體和液體的流速與壓強(qiáng)的關(guān)系解釋有關(guān)現(xiàn)象 教 學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
【圖片引入】就你看到的這幅圖片,你能提出一些問(wèn)題來(lái)嗎?老師有一個(gè)問(wèn)題:在火車(chē)的站臺(tái)上,標(biāo)有一道平行于鐵軌的直線。當(dāng)列車(chē)駛過(guò)時(shí),不允許旅客站在這條線內(nèi),以保證人體與鐵軌離開(kāi)足夠的距離。你知道這是為什么嗎? 要解釋這個(gè)問(wèn)題,就讓我們一起來(lái)做幾個(gè)探究實(shí)驗(yàn)吧!【實(shí)驗(yàn)】研究氣流的流速與壓強(qiáng)的關(guān)系
1)找一條薄紙帶,捏住紙的一端,讓紙自然下垂,當(dāng)你用嘴朝水平方向吹氣時(shí),你會(huì)發(fā)現(xiàn)什么現(xiàn)象?若改變吹氣的力量和速度,紙帶會(huì)發(fā)生什么變化? 現(xiàn)象:紙向上飄起
2)找兩張相同的薄紙,用手捏住兩張紙的一端,讓兩張紙自然下垂,相距3-5厘米,并使兩張紙保持平行。沿兩張紙的中間向下吹氣時(shí),猜測(cè)會(huì)出現(xiàn)的現(xiàn)象。試一試,結(jié)果與你的猜測(cè)相同嗎?
學(xué)生猜測(cè):紙條會(huì)被氣流向兩邊吹開(kāi) 現(xiàn)象:當(dāng)吹氣時(shí),兩紙條反而向中間合攏 分析:吹氣時(shí)紙條為什么會(huì)向中間合攏呢?
肯定是紙條受到了力的作用,而且力的方向是指向內(nèi)側(cè)。那么是什么物體施與紙條力的作用
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呢?我們分析一下:與紙條接觸的只有空氣。吹氣前,兩條紙互相平行,保持一定的間距,沒(méi)有吸引和推斥,表明它們受到外側(cè)和內(nèi)側(cè)的力互相平衡;吹氣時(shí),兩條紙相互靠近。紙條外側(cè)的氣體壓強(qiáng)沒(méi)有發(fā)生變化,說(shuō)明是紙條內(nèi)側(cè)的氣體壓強(qiáng)變小了。吹氣時(shí)與不吹氣時(shí)有什么不同嗎??jī)杉垪l內(nèi)側(cè)的氣體的流速較大。
可見(jiàn),氣體流速的改變,改變了氣體的壓強(qiáng);而且是氣體的流速越大,壓強(qiáng)越小。【教師】現(xiàn)在你能解釋在火車(chē)站的站臺(tái)上,人為什么要與行駛的列車(chē)保持適當(dāng)距離了嗎? 行駛的火車(chē)和人之間的氣流速度大,壓強(qiáng)變小。人外側(cè)的大氣壓大于火車(chē)和人之間的氣壓。這種情況下,會(huì)使人大氣壓擠到火車(chē)前,這樣非常危險(xiǎn)。
【實(shí)驗(yàn)】把一支玻璃管插入水中,當(dāng)用另一支玻璃管對(duì)著它的上端吹氣時(shí),有什么現(xiàn)象?試一試,怎樣對(duì)此現(xiàn)象作出解釋。現(xiàn)象:有水從管口吹出。
解釋?zhuān)翰AЧ艿纳隙藲饬魉俣却螅瑝簭?qiáng)小(小于大氣壓)。所以玻璃管中的水在大氣壓的作用下從管口出來(lái)。
【教師】跟氣體一樣,液體的壓強(qiáng)也會(huì)隨著流速的增大而減小。
講述:在1912年秋季的一天,當(dāng)時(shí)世界上最大的遠(yuǎn)洋輪之一“奧林匹克號(hào)”正在大海上航行,離它100米左右的地方,有一艘比它小得多的鐵甲巡洋艦“豪克號(hào)”與它平行疾駛。突然,小軍艦偏離了航道,一個(gè)勁地向“奧林匹克號(hào)”沖去,結(jié)果與“奧林匹克號(hào)”相撞。大家肯定知道原因了。首先大家要明白:水流動(dòng)而船不動(dòng)與船運(yùn)動(dòng)而水不動(dòng)效果時(shí)相同的,即運(yùn)動(dòng)是相對(duì)的(畫(huà)圖說(shuō)明)。
當(dāng)兩船彼此接近平行行駛時(shí),兩船之間的水由于被擠在一起,流速要比外部大一些,壓強(qiáng)就要比外部小一些。這樣,水流的壓力差將使兩船相互“吸引”,外部壓強(qiáng)較大的水就把兩船擠在一起而發(fā)生碰撞事故。
因此,同方向高速平行行駛的船舶要保持一定的距離。
【教師】氣體和液體一樣,受到外界環(huán)境影響時(shí)都會(huì)流動(dòng),并且流動(dòng)的規(guī)律也相同,因此人們將液體和氣體統(tǒng)稱(chēng)為流體。關(guān)于流體有兩個(gè)著名的定理:連續(xù)性定理和伯努利定理。伯努利定理:流體在一個(gè)管道中流動(dòng)時(shí),流速大的地方壓力小,流速小的地方壓力大。
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流體的連續(xù)性定理:當(dāng)流體連續(xù)不斷而穩(wěn)定地流過(guò)一個(gè)粗細(xì)不等的管道時(shí),由于管道中任何一部分的流體都不能中斷或擠壓起來(lái),因此在同一時(shí)間內(nèi),流進(jìn)任一切面的流體的質(zhì)量和從另一切面流出的流體質(zhì)量是相等的。
【教師】當(dāng)我們了解了伯努利定理后,我們可以深入了解飛機(jī)的飛行原理。我們發(fā)現(xiàn)機(jī)翼的翼型不是平的,而是平凸型的。(圖示)【實(shí)驗(yàn)】紙飛機(jī)機(jī)翼上升實(shí)驗(yàn)
我們發(fā)現(xiàn):空氣流到機(jī)翼前緣后,分成上下兩股氣流,分別沿機(jī)翼的上下表面流過(guò),在機(jī)翼后緣又重新匯合向后流去。機(jī)翼的上表面凸起,使流速加快,壓強(qiáng)減小;而機(jī)翼的下表面流速小,壓強(qiáng)增大。于是在機(jī)翼的上下表面出現(xiàn)了壓強(qiáng)差,就有了壓力差,這成為飛機(jī)上升的動(dòng)力。當(dāng)升力大于飛機(jī)重力的時(shí)候,飛機(jī)就可以升空了。【補(bǔ)充】實(shí)驗(yàn)并解釋現(xiàn)象
1、吹蠟燭
2、吹不下來(lái)的乒乓球)
3、懸空的豌豆(先教師演示懸空的乒乓球)【分析題】:
1、用細(xì)線吊起一個(gè)空的塑料瓶,用手轉(zhuǎn)動(dòng)飲料瓶,使它繞對(duì)稱(chēng)軸線旋轉(zhuǎn)。轉(zhuǎn)動(dòng)的塑料瓶帶動(dòng)四周的空氣繞它旋轉(zhuǎn)。如果這時(shí)用電
風(fēng)扇向它吹風(fēng),由于瓶的轉(zhuǎn)動(dòng),它兩側(cè)的風(fēng)速將不一樣。按照氣流和壓強(qiáng)的關(guān)系,旋轉(zhuǎn)著的飲料瓶應(yīng)當(dāng)向哪個(gè)分析移動(dòng)?
2、乒乓球前進(jìn)中由于不同的旋轉(zhuǎn)方向會(huì)沿不同的徑跡運(yùn)動(dòng),且乒乓球旋轉(zhuǎn)時(shí)會(huì)帶動(dòng)周?chē)諝獾男D(zhuǎn)。運(yùn)動(dòng)員用三種不同的擊球方法把乒乓球擊出,請(qǐng)判斷,圖中1、2、3三條徑跡哪一條是上旋球(球沿逆時(shí)針?lè)较蛐D(zhuǎn)),哪一條是下旋球(球沿順時(shí)針?lè)较蛐D(zhuǎn)),哪一條是不旋球。試說(shuō)明為什么上旋球應(yīng)該沿著你所選的徑跡運(yùn)動(dòng)。【小結(jié)】流速與壓強(qiáng)的關(guān)系 軼事記錄 課后反思
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本節(jié)課為公開(kāi)課。注重實(shí)驗(yàn)和探究,把一些實(shí)驗(yàn)通過(guò)各種方式聯(lián)系起來(lái),有屬于探究的,有屬于驗(yàn)證的,也有屬于趣味的和綜合的。
學(xué)智教育
第4節(jié)
大氣壓與人類(lèi)生活
教學(xué)目標(biāo)
1、了解大氣壓對(duì)天氣的影響,能說(shuō)出晴朗的天氣氣壓較高,陰雨的天氣氣壓較低。
2、了解大氣壓對(duì)人體的影響,氣壓變化過(guò)大會(huì)使人產(chǎn)生不良的反應(yīng)。
3、了解液體的沸點(diǎn)與壓強(qiáng)的關(guān)系:當(dāng)氣壓增大時(shí),液體的沸點(diǎn)升高;當(dāng)氣壓減小時(shí),液體的沸點(diǎn)降低。并會(huì)用這一結(jié)論來(lái)解釋有關(guān)現(xiàn)象和解決簡(jiǎn)單的實(shí)際問(wèn)題。
4、了解大氣壓在真空保存袋、吸塵器等生活用具中所起的作用。通過(guò)探究吸塵器內(nèi)部結(jié)構(gòu)的過(guò)程,學(xué)習(xí)黑箱問(wèn)題的解決方法。重點(diǎn)難點(diǎn)分析
重點(diǎn):氣壓對(duì)天氣的影響 難點(diǎn):探究吸塵器內(nèi)部結(jié)構(gòu) 課程資源的準(zhǔn)備與開(kāi)發(fā) 實(shí)驗(yàn)、實(shí)物展示
教、學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
一、大氣壓對(duì)天氣的影響
1、大氣壓的特點(diǎn):
1)、大氣壓隨高度的增大而減小
2)、同一高度的不同區(qū)域,大氣壓的數(shù)值也不一定相同 3)、同一地點(diǎn)的不同時(shí)間,大氣壓也會(huì)不同
2、大氣壓對(duì)天氣的影響:
高氣壓多晴朗天氣,低氣壓區(qū)多陰雨天氣。(畫(huà)圖說(shuō)明)
二、大氣壓對(duì)人體的影響 大氣壓對(duì)人體有一定的影響:
1、人的情緒、心情受氣壓影響較大
2、人對(duì)氣壓的變化有逐步適應(yīng)的過(guò)程(高山病的說(shuō)明)
3、減壓實(shí)驗(yàn)說(shuō)明:人體內(nèi)也有壓強(qiáng)。當(dāng)體內(nèi)外壓強(qiáng)失去平衡后,也會(huì)對(duì)人體產(chǎn)生不良的影響。
學(xué)智教育
【討論】我們的周?chē)拇髿鈮捍蠹s有105帕,這么大的氣壓作用在我們身上,我們?yōu)槭裁礇](méi)有感覺(jué)?
--猜測(cè)原因:可能時(shí)我們已經(jīng)適應(yīng)了,也可能時(shí)我們的體內(nèi)也有壓強(qiáng),它跟體外的大氣壓相平衡。
【閱讀】宇航員為什么要穿上宇航服?
三、氣壓對(duì)液體沸點(diǎn)的影響:
【提出問(wèn)題】為什么高山上用普通的鍋難以將飯煮熟? 【實(shí)驗(yàn)】研究液體的沸點(diǎn)和氣壓的關(guān)系 【現(xiàn)象】增大氣壓時(shí)原來(lái)沸騰的水不再沸騰 減小氣壓時(shí)原來(lái)不在沸騰的水又重新沸騰
【結(jié)論】液體的沸點(diǎn)與氣壓有關(guān):當(dāng)氣壓增大時(shí),液體的沸點(diǎn)升高;當(dāng)氣壓減小時(shí),液體的沸點(diǎn)會(huì)降低。
【練習(xí)】用該知識(shí)點(diǎn)解釋現(xiàn)象:
1、高壓鍋煮飯的原理
2、低壓鍋的原理
四、生活用品與大氣壓
1、真空壓縮保存袋;
2、吸塵器吸塵器是怎樣工作的 【為什么做】
吸塵器是利用大氣壓工作的一種清潔工具。你可能使用過(guò)它:當(dāng)吸塵器接上電源工作時(shí),外面帶著塵垢的空氣會(huì)從地刷的入口進(jìn)入吸塵器,而凈化的空氣則從吸塵器的尾部排出。可是你知道吸塵器的內(nèi)部結(jié)構(gòu)和工作原理嗎?恐怕很多同學(xué)和你一樣不了解。那么就讓我們帶著這個(gè)任務(wù)來(lái)進(jìn)行下面的探究活動(dòng)吧!【怎樣做】
首先讓我們提出問(wèn)題:吸塵器要達(dá)到吸塵的目的,內(nèi)部應(yīng)有什么結(jié)構(gòu)?說(shuō)說(shuō)各個(gè)器件在吸塵器中的作用。(要起塵,應(yīng)該有地面刷;要吸塵,必須使地面刷前端的空氣能進(jìn)入吸塵器,這
學(xué)智教育
就需要有風(fēng)機(jī)使吸塵器中的空氣高速排出;濾塵,則需要濾塵器(袋))。
那么,在吸塵器的工作過(guò)程中,大氣壓的作用又表現(xiàn)在哪里?(其實(shí)吸塵器靠電動(dòng)機(jī)高速驅(qū)動(dòng)風(fēng)機(jī)葉輪旋轉(zhuǎn),使空氣高速排出,而風(fēng)機(jī)前端吸塵部分的空氣不斷地補(bǔ)充風(fēng)機(jī)中的空氣,致使吸塵器內(nèi)部產(chǎn)生瞬時(shí)真空,和外界大氣壓形成負(fù)壓差。在此壓差的作用下,吸入含灰塵的空氣,經(jīng)濾塵器過(guò)濾,排出清凈的空氣,負(fù)壓差越大風(fēng)量越大,則吸塵能力也越大。)接著根據(jù)你和同學(xué)的生活經(jīng)驗(yàn)和知識(shí)經(jīng)驗(yàn),你認(rèn)為各個(gè)器件應(yīng)該怎樣連接呢?如長(zhǎng)接管與地面刷、彎管、軟管與吸塵器、吸塵器內(nèi)部器件的連接等。
最后,與其他小組交流,看看誰(shuí)的描述更合理;并與老師出示的吸塵器內(nèi)部結(jié)構(gòu)實(shí)物或圖,看看你的描述與實(shí)際情形是否相接近? 【學(xué)到了什么】
通過(guò)在教師指導(dǎo)下的探究活動(dòng),你能夠體會(huì)到科學(xué)知識(shí)在生活實(shí)際中的應(yīng)用――吸塵器就是利用大氣壓來(lái)工作的。
你一定對(duì)你在探究中出現(xiàn)的偏差有了更深的認(rèn)識(shí),體驗(yàn)到了探索科學(xué)的道路是不平坦的。通過(guò)這樣的探究活動(dòng)也培養(yǎng)了我們探索科學(xué)的精神、科學(xué)素養(yǎng)、信息素養(yǎng)、技術(shù)素養(yǎng)。我們從問(wèn)題的提出、證據(jù)的收集、方案的制訂和實(shí)施到解釋的形成,檢驗(yàn)和結(jié)論的得出等等都是我們的自主發(fā)現(xiàn)。【進(jìn)一步的研究】
知道了吸塵器的內(nèi)部結(jié)構(gòu)和工作原理,你肯定很想知道使用吸塵器應(yīng)該注意什么。下面就是有關(guān)吸塵器的使用及保養(yǎng)的小竅門(mén),供你參考。
1、吸塵器工作時(shí)應(yīng)避免開(kāi)關(guān)頻繁啟動(dòng)以免啟動(dòng)電流沖擊過(guò)大,燒壞電器設(shè)備。
2、注意墻壁電源及電源接線板插接牢固,以防止非人為因素電源開(kāi)關(guān)的瀕繁啟動(dòng)。
3、桶外軟管部分及按口部分,應(yīng)避免用力拉撞,防止這些部件損壞。
4、因吸塵器的輪子為萬(wàn)向輪,其運(yùn)動(dòng)方向有隨意性,固在工作中拉動(dòng)吸塵器時(shí),應(yīng)防止撞壞其他物品及自身輪子。
5、吸塵器的過(guò)濾網(wǎng)罩應(yīng)及時(shí)清洗以防灰塵雜物過(guò)多堵死過(guò)濾網(wǎng),增大電機(jī)工作負(fù)荷。
6、工作中,應(yīng)將地毯上的較大雜物預(yù)先清理,以防止牙簽、發(fā)卡、圖釘?shù)瓤ㄗ≤浌芗捌?/p>
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他部位。
7、為使集塵箱內(nèi)干凈、整潔,建議使用吸塵袋(須另配)。
8、使用完畢后,應(yīng)將吸塵器及塵桶內(nèi)外、軟管、扒頭、電線擦拭干凈以備下次使用。
9、吸塵器如無(wú)特殊吸水功能,嚴(yán)禁用于吸水處理。
10、除塵刷上刷毛如磨損嚴(yán)重,應(yīng)及時(shí)更換。吸塵器的電機(jī)軸承,應(yīng)定期加潤(rùn)滑油。吸塵器電機(jī)的炭刷,長(zhǎng)期使用后如產(chǎn)生磨損,應(yīng)更換新炭刷。吸塵器內(nèi)的密封膠墊若老化,應(yīng)更換新膠墊。
11、如遇緊急情況出現(xiàn)故障時(shí)應(yīng)馬上停機(jī),通報(bào)有關(guān)部門(mén)管理人員,找廠家及經(jīng)銷(xiāo)商專(zhuān)業(yè)維修人員進(jìn)行維修。
3、離心式水泵、活塞式抽水機(jī)(用圖分析)利用大氣壓工作
說(shuō)明為什么在啟動(dòng)機(jī)器前要先灌滿水以及工作的主要過(guò)程。軼事記錄
實(shí)驗(yàn)很成功。充分說(shuō)明知識(shí)的呈現(xiàn)可以通過(guò)實(shí)驗(yàn)探究來(lái)實(shí)現(xiàn)。課后反思
本節(jié)課能聯(lián)系實(shí)際,學(xué)生較容易理解和掌握。學(xué)生對(duì)這塊內(nèi)容
學(xué)智教育
第5節(jié)
風(fēng)
教學(xué)目標(biāo)
1、了解風(fēng)是怎樣形成的
2、知道風(fēng)向、風(fēng)速的表示方法和度量單位
3、學(xué)會(huì)用風(fēng)向標(biāo)、風(fēng)速儀測(cè)定風(fēng)向和風(fēng)速的方法
4、了解風(fēng)對(duì)人類(lèi)活動(dòng)和動(dòng)物行為的影響 重點(diǎn)難點(diǎn)分析 重點(diǎn):風(fēng)的觀測(cè)
難點(diǎn):風(fēng)的形成;目測(cè)風(fēng)向、風(fēng)速 課程資源的準(zhǔn)備與開(kāi)發(fā)
風(fēng)速儀和風(fēng)向標(biāo),并實(shí)地測(cè)試風(fēng)向和風(fēng)速
教、學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
【演示并思考】把充滿氣體的氣球充氣口松開(kāi),會(huì)感到氣球內(nèi)的空氣一涌而出,這是為什么?
一、風(fēng)
1、風(fēng)是空氣的水平運(yùn)動(dòng)。風(fēng)是從高氣壓區(qū)流向低氣壓區(qū)的。
2、風(fēng)的兩個(gè)基本要素:風(fēng)向和風(fēng)速 1)風(fēng)向是紙風(fēng)吹來(lái)的方向。天氣觀測(cè)和預(yù)報(bào)中常使用8種風(fēng)向。表示方法:用一短線段表示。用紙飛機(jī)測(cè)風(fēng)向 【為什么做】
風(fēng)向和風(fēng)速是測(cè)量風(fēng)的兩個(gè)基本要素。觀測(cè)風(fēng)向的儀器叫風(fēng)向標(biāo),由箭頭、水平桿和尾翼三部分組成。那么風(fēng)向標(biāo)是怎樣指示風(fēng)向的呢?風(fēng)向是由風(fēng)向標(biāo)箭頭的方向來(lái)指示,還是由箭
學(xué)智教育
尾的方向來(lái)指示呢?風(fēng)向又是怎么規(guī)定的呢?就讓我們用紙飛機(jī)測(cè)風(fēng)向這個(gè)簡(jiǎn)單的模擬實(shí)驗(yàn)來(lái)解決吧!【怎樣做】
折一紙飛機(jī),中間用鉛筆穿過(guò)(要讓紙飛機(jī)能在鉛筆上輕松轉(zhuǎn)動(dòng))。用手握住鉛筆,將紙飛機(jī)放在開(kāi)啟的電風(fēng)扇前,觀察紙飛機(jī)的機(jī)頭和尾翼的指向。注意:此時(shí)人要站在紙飛機(jī)的后方。并借助指南針判斷風(fēng)向。【學(xué)到了什么】
通過(guò)實(shí)驗(yàn),使我們對(duì)風(fēng)和風(fēng)向有了一個(gè)直觀的認(rèn)識(shí):紙飛機(jī)的箭頭指向風(fēng)來(lái)自的方向。同理,在氣象觀測(cè)中,風(fēng)向是由風(fēng)向標(biāo)的箭頭指向的。
同時(shí)也使我們明白:實(shí)驗(yàn)可以使我們更簡(jiǎn)潔明了地了解事物,也培養(yǎng)了我們的觀察能力。
【進(jìn)一步的研究】
(1)用紙飛機(jī)測(cè)風(fēng)向的實(shí)驗(yàn)使你明白了風(fēng)向標(biāo)指示風(fēng)向的事實(shí)。你是否在想:這是運(yùn)用了什么原理呢?為什么風(fēng)向標(biāo)會(huì)有一定的指向呢?下面的文字,會(huì)幫助你有一個(gè)了解。風(fēng)向標(biāo)是一種應(yīng)用最廣泛的測(cè)量風(fēng)向儀器的主要部件。在風(fēng)的作用下,尾翼產(chǎn)生旋轉(zhuǎn)力矩使風(fēng)向標(biāo)轉(zhuǎn)動(dòng),并不斷調(diào)整指向桿指示風(fēng)向。風(fēng)向標(biāo)感應(yīng)的風(fēng)向必須傳遞到地面的指示儀表上,以觸點(diǎn)式最為簡(jiǎn)單,風(fēng)向標(biāo)帶動(dòng)觸點(diǎn),接通代表風(fēng)向的燈泡或記錄筆電磁鐵,作出風(fēng)向的指示或記錄,但它的分辨只能做到一個(gè)方位(22.5°)。
地面風(fēng)指離地平面10─12 米高的風(fēng)。風(fēng)的來(lái)向?yàn)轱L(fēng)向,一般用十六方位或360°表示。以360°表示時(shí),由北起按順時(shí)針?lè)较蚨攘俊?/p>
(2)你知道了風(fēng)向的測(cè)量方法,一定很想知道風(fēng)速大小的測(cè)量方法。其實(shí)你也可以用簡(jiǎn)單的模擬實(shí)驗(yàn)來(lái)測(cè)量風(fēng)速。請(qǐng)認(rèn)真閱讀下面的文字,你就會(huì)用生活中常見(jiàn)的小風(fēng)車(chē)(參見(jiàn)三維風(fēng)車(chē)式風(fēng)速儀)或風(fēng)壓板來(lái)簡(jiǎn)單比較風(fēng)速的大小了,動(dòng)手試一試。
2)風(fēng)速:指單位時(shí)間里空氣在水平方向上移動(dòng)的距離,其單位是:米/秒、千米/時(shí)或海里/小時(shí)表示。
測(cè)試風(fēng)速的儀器叫風(fēng)速計(jì),它利用風(fēng)杯在風(fēng)作用下的旋轉(zhuǎn)速度來(lái)測(cè)量風(fēng)速。風(fēng)速儀有以下幾種:①風(fēng)杯風(fēng)速表②槳葉式風(fēng)速表③熱力式風(fēng)速表。
學(xué)智教育
風(fēng)速常用風(fēng)級(jí)表示。
【閱讀】各風(fēng)級(jí)的名稱(chēng)、風(fēng)速和目測(cè)結(jié)果
3)風(fēng)對(duì)人類(lèi)的生活有很大的影響,有些動(dòng)物的行為也和風(fēng)有關(guān)。【小結(jié)】 【補(bǔ)充】 風(fēng)
車(chē)
荷蘭利用風(fēng)能歷史悠久,自古以來(lái)就是世界聞名的“風(fēng)車(chē)之鄉(xiāng)”,這與其優(yōu)越的自然條件、不屈的民族精神和優(yōu)秀的民族智慧是分不開(kāi)的。
荷蘭位于北緯50°50′~北緯53°30′之間,在全球大氣環(huán)流所形成的風(fēng)系中,正好處于西風(fēng)帶,常年盛行西風(fēng),由于荷蘭國(guó)土的60%海拔低于1米,近40%的國(guó)土低于海平面,最高處海拔也僅300米左右,是世界上有名的“低地之國(guó)”,來(lái)自大西洋的西風(fēng)能夠長(zhǎng)驅(qū)直入內(nèi)陸,全國(guó)風(fēng)力資源極為豐富。風(fēng)車(chē)是荷蘭人智慧的結(jié)晶。據(jù)說(shuō),世界上第一臺(tái)風(fēng)車(chē)是荷蘭人在同大自然的博斗中,于1408年發(fā)明的。到19世紀(jì)時(shí),全國(guó)已擁有風(fēng)車(chē)18000多臺(tái),最大的有9層樓高,風(fēng)翼長(zhǎng)達(dá)20米,無(wú)怪乎人們叫它“風(fēng)車(chē)王國(guó)”了。
荷蘭的風(fēng)車(chē)種類(lèi)很多,從最古老的建于1450年的塔式風(fēng)車(chē)到后來(lái)的軸式風(fēng)車(chē),都是精工制作的,顯示了荷蘭人無(wú)比的智慧和高超的工藝。荷蘭素以修筑海堤圍海造田而著稱(chēng)于世。攔海造田,成為荷蘭人奮斗精神的象征,而風(fēng)車(chē)則成為荷蘭人向大海奪取土地的強(qiáng)有力的武器,大小風(fēng)車(chē)日夜轉(zhuǎn)動(dòng),起到了排出海水、灌溉田地的巨大作用,在荷蘭人向大海奪取土地的斗爭(zhēng)中立下了豐功偉績(jī)。同時(shí)風(fēng)車(chē)還被廣泛用于榨油、脫谷等生產(chǎn)勞動(dòng)中,為荷蘭歷史上的繁榮與發(fā)展起到了巨大作用。
20世紀(jì)以來(lái),隨著電力和內(nèi)燃機(jī)的使用,傳統(tǒng)的風(fēng)車(chē)已難現(xiàn)昔日的輝煌,逐漸銷(xiāo)聲匿跡了,但仍有上千臺(tái)被保留下來(lái),成為供參觀考察的景物。例如:在肯德代克,建于1740年的風(fēng)車(chē)每年吸引著20萬(wàn)到30萬(wàn)的參觀考察者。近年來(lái),隨著能源危機(jī)和大量礦物能源的使用對(duì)地球環(huán)境的破壞,風(fēng)能利用重新得到人們的青睞,古老的風(fēng)
車(chē)脫胎換骨,為荷蘭的鄉(xiāng)村和城市帶來(lái)源源不斷的電能。
軼事記錄
學(xué)智教育
學(xué)生能針對(duì)幾個(gè)具體的實(shí)物--風(fēng)速儀和風(fēng)向標(biāo),提出各種各樣的問(wèn)題,很值得肯定。課后反思
這種課目的是增強(qiáng)學(xué)生的生活常識(shí),所以要在激發(fā)學(xué)生學(xué)習(xí)興趣和課外知識(shí)拓展這兩個(gè)方面上下功夫。
學(xué)智教育
第7節(jié)
教學(xué)目標(biāo)
1、知道獲取天氣預(yù)報(bào)的常見(jiàn)方法。
2、學(xué)會(huì)看天氣預(yù)報(bào)。
明天的天氣會(huì)怎么樣
3、學(xué)會(huì)看簡(jiǎn)單的天氣圖。掌握天氣圖上重要的天氣系統(tǒng)。
4、利用天氣圖判斷天氣狀況,并能做簡(jiǎn)單的天氣預(yù)報(bào)。
5、知道天氣預(yù)報(bào)信息的主要收集方法。
6、調(diào)查當(dāng)?shù)氐奶鞖庵V語(yǔ),能解釋其中的科學(xué)道理。重點(diǎn)難點(diǎn)分析
重點(diǎn):怎樣看天氣預(yù)報(bào);
天氣圖上的常見(jiàn)天氣系統(tǒng); 天氣圖和天氣形勢(shì);
難點(diǎn):天氣圖上的等壓線和天氣系統(tǒng);
簡(jiǎn)單的天氣預(yù)報(bào)。教、學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
【引入】根據(jù)學(xué)生預(yù)習(xí)作業(yè)交流收集當(dāng)天當(dāng)?shù)氐奶鞖忸A(yù)報(bào)的方法。
一、獲取天氣預(yù)報(bào)的常用方法:
⑴通過(guò)看電視、聽(tīng)廣播、撥氣象預(yù)報(bào)電話、互聯(lián)網(wǎng)上查看等獲取氣象預(yù)報(bào)信息 ⑵通過(guò)分析天氣圖,自己預(yù)測(cè)天氣 ⑶通過(guò)氣象觀測(cè),自己制作天氣預(yù)報(bào)
二、怎樣看天氣預(yù)報(bào) 了解天氣預(yù)報(bào)用語(yǔ)的含意
⑴“陰”指天空的總云量在8/10以上,“多云”指天空總云量在5/10到7/10,5/10到3/10為少云,3/10 以下為晴。
⑵12小時(shí)內(nèi)降水小于5毫米為小雨,5-15毫米為中雨,大于15毫米為大雨。降水概率表示降水的可能性大小。
學(xué)智教育
⑶最低氣溫和最高氣溫的表示方法。⑷空氣質(zhì)量指數(shù)
三、天氣圖
--用來(lái)表示天氣形勢(shì),是一種可以表現(xiàn)不同地方氣象信息的地圖。
⒈分析天氣圖時(shí),首先要了解一些重要的術(shù)語(yǔ)(以圖2-47為例)
⑴等壓線:氣壓相等的地方的連線。根據(jù)等壓線的分布特點(diǎn),可以分析出常見(jiàn)的天氣系統(tǒng),如高壓、冷鋒等
⑵鋒是影響天氣的重要天氣系統(tǒng)。冷暖空氣的交界面叫鋒面;向暖空氣一側(cè)移動(dòng)的鋒叫冷鋒,常帶來(lái)降雨、大風(fēng)和降溫天氣;向冷空氣一側(cè)移動(dòng)的鋒叫暖鋒,常帶來(lái)降雨天氣,氣溫升高。
⑶高壓、低壓、臺(tái)風(fēng)等。還要明白鋒面系統(tǒng)的移動(dòng)機(jī)理,高氣壓和的氣壓系統(tǒng)的移動(dòng)機(jī)理等。
⒉觀測(cè)天氣圖上的圖例,如暖鋒、冷鋒,還有天氣圖上的日期等。明確冷鋒、暖鋒系統(tǒng)及鋒面,同時(shí)關(guān)注等壓線上的數(shù)字來(lái)得知高壓區(qū)和低壓區(qū)。然后根據(jù)鋒面系統(tǒng)的移動(dòng)方向來(lái)判斷該鋒面系統(tǒng)對(duì)所預(yù)報(bào)地區(qū)產(chǎn)生的影響,判斷該地的天氣趨勢(shì)。
【學(xué)生練習(xí)】制作天氣預(yù)報(bào)
學(xué)智教育
第8節(jié)
氣候和影響氣候的因素
教學(xué)目標(biāo)
⒈了解氣候的概念及影響氣候的因素 ⒉了解緯度因素對(duì)氣候的影響
⒊理解比熱的概念,了解不同物質(zhì)比熱的差異 ⒋理解陸地和海洋比熱的不同對(duì)氣溫的影響 ⒌理解地形因素對(duì)氣溫和降水的影響
⒍了解季風(fēng)的概念,理解我國(guó)季風(fēng)的形成舉機(jī)理 重點(diǎn)難點(diǎn)分析
重點(diǎn):不同物質(zhì)的比熱;
海洋和陸地的性質(zhì)對(duì)氣溫和降水的影響; 地形對(duì)氣溫和降水的影響; 季風(fēng)的形成
難點(diǎn):比熱的概念;
海洋和陸地的性質(zhì)對(duì)氣溫和降水的影響;
地形對(duì)降水的影響;
季風(fēng)的形成
教、學(xué) 預(yù) 設(shè)調(diào) 控 對(duì) 策
一、氣候
⒈氣候的含義:氣候是指某一地區(qū)長(zhǎng)時(shí)間內(nèi)的天氣特征,包括天氣的平均狀況和極端狀況。(與天氣的概念進(jìn)行區(qū)別)
【思考】天氣與氣候有什么不同?有什么聯(lián)系?
⒉我國(guó)各地氣候差異很大,是由于不同的地區(qū)影響氣候的因素不同。
二、緯度對(duì)氣候的影響
緯度位置不同的大地區(qū),接受太陽(yáng)輻射的量不同,在地球上所處的溫度帶位置也不同。【復(fù)習(xí)】根據(jù)接受太陽(yáng)輻射的多少,地球表面分成五個(gè)溫度帶。
學(xué)智教育
【討論】我國(guó)的緯度位置跨五帶中的哪幾帶? 【分析】海南和漠河的氣候特征
三、海洋和陸地的性質(zhì)對(duì)氣溫和降水的影響
【提出問(wèn)題】夏天沿海地區(qū)與內(nèi)陸地區(qū)相比要涼爽得多,夏天的內(nèi)陸和沿海氣溫有較大的差異,為什么?
【實(shí)驗(yàn)】探究相同質(zhì)量的不同物質(zhì),升高相同的溫度,吸收的熱量是否相同?
【過(guò)程】
1、實(shí)驗(yàn)器材:燒杯(質(zhì)量要盡可能相同)一對(duì),溫度計(jì)一對(duì),帶鐵圈、鐵夾的鐵架臺(tái)一對(duì),酒精燈(火焰大小要一致)一對(duì),石棉網(wǎng)一對(duì),天平;水和煤油等。
2、把兩個(gè)同樣的燒杯放在天平的兩盤(pán)中,分別向杯內(nèi)倒入半杯水和半杯煤油,并使天平平衡,水與煤油的質(zhì)量相等。按圖2-50所示裝配好裝置,然后用相同的酒精燈(實(shí)驗(yàn)時(shí),為了使酒精燈加熱效果相同,必須把石棉網(wǎng)調(diào)到相同的高度)加熱,使它們?cè)谙嗤臅r(shí)間內(nèi)里吸收相同的熱量。兩杯的初溫應(yīng)該是相同的。如果不同,可用酒精燈稍加熱進(jìn)行調(diào)整。
3、經(jīng)過(guò)一段時(shí)間加熱后,觀察溫度計(jì)的示數(shù)變化,是水中還是煤油中的溫度升高得快? 【結(jié)論】
1、實(shí)驗(yàn)表明:在吸收相同的熱量時(shí),煤油的溫度比水的溫度升高得快。也就是說(shuō),相同質(zhì)量的水和煤油升高相同的溫度時(shí),水要多加熱一些時(shí)間,即水要吸收更多的熱量。
2、以上的實(shí)驗(yàn)反映了水與煤油這兩種物質(zhì)的不同性質(zhì)。以此延伸,就是質(zhì)量相同的不同物質(zhì),升高相同的溫度時(shí),所吸收的熱量是不同的。
㈠比熱:我們把1單位質(zhì)量的某種物質(zhì),在升高1℃使所吸收的熱量,叫做這種物質(zhì)的比熱容,簡(jiǎn)稱(chēng)為比熱。
㈡比熱單位:焦/(千克.℃)
讀作:焦每情千克攝氏度
符號(hào):J/(kg.℃)㈢水的比熱:4.2×103焦/(千克.℃)表示的含義是什么? ㈣比熱表的閱讀:
得出:⑴水的比熱最大。(由此說(shuō)明水作冷卻劑、保溫劑的作用)
學(xué)智教育
⑵不同物質(zhì)的比熱是不同的。所以比熱是物質(zhì)的一種特性。與物質(zhì)的質(zhì)量、升高的溫度、吸放熱的多少無(wú)關(guān)
⑶不同狀態(tài)的同一種物質(zhì)的比熱不同,說(shuō)明比熱與物質(zhì)狀態(tài)有關(guān)。
【思考】比較水和砂、土的比熱大小,說(shuō)說(shuō)海洋和陸地會(huì)對(duì)氣候產(chǎn)生什么不同的影響? 【分析】我國(guó)一月和七月的平均氣溫分布圖,驗(yàn)證猜想 【思考】海洋對(duì)沿海地區(qū)降水的影響
【小結(jié)】海洋和陸地的性質(zhì)對(duì)氣溫和降水的影響:海洋和陸地的性質(zhì)不同,對(duì)降水和氣溫的影響不同。海洋使得氣溫變化小,降水豐富。
四、地形對(duì)氣溫和降水的影響
⒈氣溫隨著地勢(shì)的升高而降低。一般海拔增高1000米,氣溫會(huì)下降約6℃。⒉山地的迎風(fēng)坡比背風(fēng)坡多雨,向陽(yáng)坡比背陽(yáng)坡氣溫高。【討論】為什么迎風(fēng)坡多雨,背風(fēng)坡少雨?
五、季風(fēng)
⒈季風(fēng)是在不同的季節(jié)里風(fēng)向相反和接近相反的風(fēng)。【討論】并將討論結(jié)果填圖。
⑴同一緯度的大陸和海洋,冬季和夏季的氣溫分別是哪個(gè)高?(要求分析是什么原因所致:源于海洋和陸地的熱力性質(zhì)差異)
⑵這種溫度的季節(jié)性變化對(duì)氣壓高低分布有什么影響? ⑶大陸和海洋高氣壓和低氣壓的變化對(duì)風(fēng)向產(chǎn)生什么影響?
⒉世界上季風(fēng)區(qū)域很廣,以亞洲季風(fēng)最盛行。我國(guó)冬季盛行偏北風(fēng),夏季盛行偏南風(fēng)。【思考】P90的思考題 【小結(jié)】
影響氣候的重要因素:緯度位置、海陸分布和地形、季風(fēng)等。軼事記錄
學(xué)生對(duì)比熱的知識(shí)解釋生活中的現(xiàn)象很感興趣,科學(xué)知識(shí)深深地吸引著學(xué)生。實(shí)驗(yàn)直觀明了,學(xué)生易于接受。
學(xué)智教育
課后反思
本節(jié)內(nèi)容安排2課時(shí)。第一課時(shí)上至海陸分布對(duì)氣候的影響。
第9節(jié)
中國(guó)東部的季風(fēng)雨西部的干旱氣候
教學(xué)目標(biāo)
⒈了解我國(guó)季風(fēng)氣候的類(lèi)型和分布
⒉學(xué)會(huì)根據(jù)氣候資料分析我國(guó)季風(fēng)氣候的特點(diǎn) ⒊學(xué)會(huì)根據(jù)氣候資料分析我國(guó)西部干旱氣候的特點(diǎn) ⒋知道氣候變化雨動(dòng)物行為的關(guān)系
⒌了解氣候?qū)θ祟?lèi)生產(chǎn)生活的影響,以及如流對(duì)氣候資源的利用 ⒍知道寒潮、臺(tái)風(fēng)、洪水等災(zāi)害性天氣的成因和危害
⒎關(guān)注人類(lèi)活動(dòng)對(duì)氣候的影響,初步建立人地和諧的氣候資源觀。重點(diǎn)難點(diǎn)分析
重點(diǎn):中國(guó)東部的季風(fēng)雨西部的干旱氣候的特點(diǎn)及對(duì)人類(lèi)活動(dòng)的影響;
人類(lèi)活動(dòng)雨洪水;
人類(lèi)活動(dòng)對(duì)氣候的影響
難點(diǎn):中國(guó)東部的季風(fēng)雨西部的干旱氣候的特點(diǎn)分析;
人類(lèi)活動(dòng)與洪水 教、學(xué) 預(yù) 設(shè) 調(diào) 控 對(duì) 策
一、東部季風(fēng)氣候
1、季風(fēng)氣候區(qū)是指夏季風(fēng)能夠到達(dá)的地區(qū)。
2、我國(guó)在大興安嶺-陰山-賀蘭山-岡底斯山一線以東以南的地區(qū)是季風(fēng)氣候區(qū)。分布有熱帶季風(fēng)氣候、亞熱帶季風(fēng)氣候和溫度季風(fēng)氣候。
【討論】P91討論題得出:
3、我國(guó)季風(fēng)氣候的主要特點(diǎn):冬季氣溫低,降水少;夏季氣溫高,降水多,全年降水比較豐富。但南方冬季氣溫明顯高于北方,氣溫年較差小,年降水量更大。
學(xué)智教育
4、季風(fēng)氣候?qū)θ藗兩a(chǎn)、生活的影響有利有弊。
A、降水充沛,集中夏季,四季分明,雨熱同期對(duì)農(nóng)業(yè)生產(chǎn)非常有利
B、我國(guó)季風(fēng)氣候的大陸性強(qiáng),降水的年際變化很大,使我國(guó)洪澇和旱災(zāi)頻發(fā)。C、冬季的低溫又常形成寒潮、凍害、暴雪等惡劣天氣。
二、我國(guó)西部的干旱氣候
⒈夏季風(fēng)不能到達(dá)的我國(guó)西部地區(qū)一般降水稀少,為干旱各半干旱氣候區(qū)。
⒉我國(guó)西部的干旱氣候的特點(diǎn):全年降水量稀少,降水集中在夏季,季節(jié)變化大;冬季寒冷,夏季炎熱,氣溫日較差、年較差很大,但日照充沛。(形成原因的分析:西部地區(qū)深居內(nèi)陸,海洋水汽難以到達(dá)。)
⒊干旱氣候的利弊:氣溫較差大,光照時(shí)間長(zhǎng),對(duì)農(nóng)業(yè)生產(chǎn)非常有利,如棉花、瓜果的生產(chǎn)。
⒋干旱氣候區(qū)的生物在行為和形態(tài)上的適應(yīng)性:如仙人掌粗大的莖和葉刺;抬尾芥蟲(chóng)在大霧的夜里抬起屁股的做法。
三、寒潮、臺(tái)風(fēng)和洪水
1、寒潮是大范圍的強(qiáng)烈冷空氣活動(dòng)。會(huì)帶來(lái)劇烈的降溫、霜凍、大風(fēng)和揚(yáng)沙天氣。
2、臺(tái)風(fēng)是一種破壞力很大的災(zāi)害性天氣。【討論】⑴臺(tái)風(fēng)天氣的感受和自我防護(hù)知識(shí) ⑵臺(tái)風(fēng)的利弊
3、洪水是我國(guó)?最大的自然災(zāi)害之一。引發(fā)的原因:持續(xù)性的暴雨、臺(tái)風(fēng),人類(lèi)活動(dòng)。【實(shí)驗(yàn)】植被護(hù)坡實(shí)驗(yàn) 【為什么做】
持續(xù)性暴雨和臺(tái)風(fēng)使引發(fā)洪水的主要自然原因。一些人類(lèi)活動(dòng)也可以引發(fā)洪水或使洪水的危害增大。隨著人類(lèi)社會(huì)的發(fā)展,人類(lèi)活動(dòng)對(duì)洪水產(chǎn)生的影響越來(lái)越大。為什么會(huì)有這樣的說(shuō)法?現(xiàn)實(shí)呈現(xiàn)在我們面前!譬如黃河上游植被的破壞,使黃河中下游地區(qū)頻頻發(fā)生洪澇災(zāi)害。由于上游泥沙的大量流失,黃河在下游也成為了地上河,使位于黃河下游的城市時(shí)刻處在洪水的威脅之中。讓我們來(lái)做這個(gè)實(shí)驗(yàn),初步而實(shí)在地體會(huì)一下植被對(duì)水土保持的作用。
第四篇:初中英語(yǔ)全英教案
A teaching plan
教材分析 學(xué)情分析 Contents: 1.Vocabulary: 2.Structure: 3.Dialogue: 4.listening: Objectives:
1.Teaching Aims and Demands(1)Instructional Objectives
Be able to use the new words and phrases:
(2)Ability Objectives Be able to use listening skills to comprehend their dialogues, such as listen for specific information etc.Be able to use what they learned to describe what they can do and give responses.Be able to use the language they learned to finish a dialogue and a short passage.(3)Educational Objectives
Arousing students’ interest and helping them learn by using pictures.Building their confidence by step by step approach and careful scaffolding.2.Teaching Importance To master the key vocabulary
To understand and use the target language To master the usage of the different forms of “can” in the target language.3.Teaching Difficulties To enable the students to understand the sentence patterns to talk about the ability activities.To enable the students to use the target language
The students learned the structure “can do sth”, So it’s difficult and important to let them understand it can also be used to talk about the ability activities.4.Teaching Aids Multi-media computer, Tape recorder and so on.5.The Teaching Methods(1)Communicative teaching method.(2)Audio-visual teaching method.(3)Task-based teaching method.6.Studying Ways(1)Let the Ss pass “Observation—Imitation—Practice” to study language.(2)Let the Ss pay attention to the key information in listening practice.(3)Enable the Ss to study English language by Communication.(4)Let the Ss know that conclusions and being good at thinking are necessary to learn English well.Procedures and Time Allotment: 2 Task1: Warming-up(2mins)Before class, get Ss to enjoy an English song for about 2 minutes to warm them up.The purpose of the task-based activities is to Interest the students Task 2:Lead-in(3mins)1.Use the PPT to lead in the new lesson..show some pictures and teach the words and phrases: 2.ask Ss read the words together.Task3: Play a game(4mins)Task 4: Presentation(8mins)The purpose of the task-based activities is to let the students learn to cooperate with each other and practice the language points, improve the students’ abilities of speaking.Task5: Representations(5mins)Task 6.Listening(5mins)1.Ask Ss to open their books and turn to Page 59.Look at part 1b, look at the conversations and make sure the students understand the conversations and what to do.Then play the tape for three times.For the first time the students only listen to understand the whole general meaning of the conversations.For the second time the Ss pay attention to the activity in each conversation and write them in the blanks.For the third time the Ss pay attention to the time that the activities in each conversation are done and number the conversations(1-3).Ask some Ss to check their answers.2.Practice the conversations in 1b.Then make your own 3 conversations.The purpose of the task-based activities is to practice listening and improve the students’ abilities of listening.Task 7.Make a survey(7mins)
Give the students several minutes to prepare the survey using the target language to ask and answer, next fill the form : Finally ask two groups of the students to report their results.For example: Task 8.Summary(4 mins)Summarize the key language points in groups , and show them on the screen to help the Ss take notes.Task 9.Homework(2mins)1.Consolidate and review the expressions of the lesson.2.Write a short passage about the results of the survey.Blackboard design
第五篇:Module1-4全英教案
Module1 The Great Wall
1、Teaching preparing:
Students book:Module1Unit 1Activity1, 2, 3
2、Teaching task: A.basic object:
Key words:
thousand postcard more kilometer
Key sentences: “These postcards are great!” “It?s a picture of the Great Wall.” “Tell me more about the Great Wall.” “How long is it?
B.To learn “thousand
kilometer
million ” C.Review: The using way of the verb ?be? 2.
Talking about some famous places.3、Teaching point: words: thousand
kilometer
million postcard
more4、Teaching difficulty:
kilometer
thousand
million
“Tell me more about the Great Wall.“It?s a picture of the Great Wall.”
5、Task design: words: postcard
more
thousand
kilometer
million
Sentences: “These postcards are great!” “It?s a picture of the Great Wall.” “Tell me more about the Great Wall.” “How long is it?”
“It?s about six thousand seven hundred kilometers.”的句型。B.The task:
1:AB
Unit1
exercise3 2:AB
Unit2
exercise1、2、4、5
6、Teaching things Photo radio picture wordcards 第一課時(shí):
1、Warm up ⑴Greetings: T—Ss Ss—Ss
(2)Competition: List the places the visited as many as possible.2、Leading :(1)A.watch TV T: What’s this place?
S:(teacher writes the main structure on board as modal for other students)It’s a picture of … B.Game : Tell me more T: It’s an animal.S1: Tell me more
T: It has long nose.S1: It’s an elephant.The more “Tell me more”, the less will the score be given.3、(Presentation)(1)S open their books Question: Look at the pictures a.Who are they? b.Where are they? c.What are they doing? Student answer the questions.(2)listen to the tape(3)repeat after the tape.(4)Teacher explain the text and student practice the key points.a.The key points: postcard
more
thousand
kilometer
million b.The main sentences structure: “These postcards are great!” “It?s a picture of the Great Wall.” “Tell me more about the Great Wall.” “How long is it?”(6)students practice to make sentences with the key points.Game:Passing wordcards
4、Drilling and Counselling(1)Finish the exercise one(2)Pairwork
5、Teaching handwriting: “It?s a picture of the Great Wall.” “Tell me more about ……”
三.課后反思:
這堂課主要講了各個(gè)國(guó)家的一些名勝古跡,通過(guò)讓孩子描述圖片的內(nèi)容來(lái)掌握所學(xué)的句型.鍛煉他們的口頭表達(dá)能力,再讓他們自己帶一些圖片,同桌之間相互對(duì)圖片進(jìn)行描述,加深對(duì)所學(xué)知識(shí)的記憶.單詞的掌握還欠缺一點(diǎn).第二課時(shí)
Step1.Tell students a joke and give them a riddle to fun.Step2.Review the words: postcard
more
thousand
kilometer
million
Step3.Repeat the text after the tape, then students practice with partner in roles.Step4.Teacher explain the using way of “million” “thousand”: teacher give numbers, students tells “~ thousand” or “~ million”.6,000,000
34,000
12,000,000
Step5.Homework: a.word dictation b.recite paragraph one c.Students make role play about unit one.第三課時(shí)
Step1.a.Student make role play.b.Give words dictation.c.Open Activity Book.Step2.Do exercise 1.a.Students look at pictures, tell what they can see on it.Students describe.b.Students read the questions.c.Teacher gives help, students finish the question.Step3.Do exercise 2.Listen, ask and answer.a.Play the tape a second time, pauses it after each second.T: What are they? S: They are cars, trees.….b.Work in pairs, ask and answer.Step4.Do exercise 3 Complete the dialogues a.Students look at pictures, tell what they can see on it.Students describe.b.According to the pictures and words in the brackets,students fill the blank
第2單元教案 New York is in the east of America.1Teaching preparing: Student?s book:Module1Unit 2Activity1, 2, 3
2、Teaching task: A.Basic objects: Key words:Mexico
Canada Key sentences: “It?s in the north / south / west / east of China/ America…”
“Tell me more about the Great Wall.” “How long is it?” B.Review: The using way of verb ?be?
2.Making student know about famous places.Talking about some basic facts of a country or a place,and learn to use direction words:It?s in the north / south / west / east of
3、Teaching point: words:
Mexico
Canada
San Francisco
New York
4、Teaching difficulty: How to pronounce “Mexico” “It?s a picture of the Great Wall.” “Tell me more about the Great Wall.”
5、Task design Learning task: Review words:thousand
kilometer postcard
more
million
To learn vocabulary:San Francisco
New York Mexico
Canada
Learning “It?s a picture of the Great Wall.” “Tell me more about the Great Wall.”
“It?s in the north / south / west / east of China/ America…” “It?s about six thousand seven hundred kilometers.”
6、Teaching things
Radio
wordcards
photo
picture
第四課時(shí)
1、Warm up ⑴Greetings: T—Ss Ss—Ss(2)Pointing game: Teacher gives students four cards “north / south / west / east”, let students put them around the classroom.T: North.S: Students point to the north
2、(Leading)(1)A.Watch PPT T: What?s this place? S: It?s a picture of America.Students learn to read Mexico
Canada
San Francisco
New York B.a.Game : Pointing game(Students open the book, look at activity 1)T: Mexico.S: Students point to the south of the map.c.Listen to the tape, and point to the places on the map.C.Lead in
1)Student list Chinese famous cities, teacher write them on the black board.2)Teacher write the main structure on the board: “Tell me more about the …...” “Where is it?”
“It?s in the north / south / west / east of China/ America…”
“How long / big is it?”
3)Students practice with partner
3、(Presentation)(1)S open their books Question: Look at the pictures a.Who are they? b.What are they doing? Student answer the questions.(2)listen to the tape(3)repeat after the tape.4、(Drilling and Counselling)Learn the chant: a.What can you see? b.What can you see on the flag?
Teacher introduce history of American flag.c.Students listen to the tape.e.Students repeat 5.Teacher?s handwriting: “It?s a picture of the Great Wall.” “Tell me more about ……”
“It?s in the north / south / west / east of China/ America…”
三.課后反思
第五課時(shí)
Step1 Warm up: Do the chant “America”
Play a game:“What am I?”
Rules: Students can do 1~2 actions.1 action got a star, 2 actions got 2 stars.The less actions , the more stars will be given.Step2 Do activity 3.a.Listen to the tape.b.Listen again, students claps hands, they can clap harder when hear the stressed words.c.Students repeat
Step3 Do activity book Activity 1 a.T: what can you see?
S: I saw….b.Ss read the words after teacher.c.Play the tape, students write the answer.Activity 2 a.Ss read the places with teacher?s help.b.Ss write sentences, teacher offers help.Step4 Homework 1.Do exercise 3 2.words dictation.課后反思:
課本中出現(xiàn)了東南西北方位詞,雖然不是重點(diǎn),但還是應(yīng)該拿出來(lái)給孩子們復(fù)習(xí)復(fù)習(xí).通過(guò)對(duì)這個(gè)模塊的一個(gè)小測(cè)驗(yàn),發(fā)現(xiàn)孩子們對(duì)基本知識(shí)的掌握不夠扎實(shí).《英語(yǔ)》六年級(jí)第七冊(cè)第2模塊
第1單元教案 Chinatown in America
1Teaching preparing
Students? book:Module2 Unit 1 Activity1, 2, 3
2、Teaching task 2.Basic task Key words:miss
sometimes
restaurant
really Key sentences“There?s a Chinatown in New York!” “There are lots of Chinese shops and restaurants there”.B know about “l(fā)ots of”
C.Review:
The using way of the verb ?There be? 2.To describe places
3、Teaching point:
dancing
words:
sometimes
restaurant
really Teaching difficulty How to pronounce words ?sometimes
restaurant? To learn the structure “There be”
5、Task design A.Learning task Key words: miss
sometimes
restaurant
really
dancing
Key structure: “There?s a Chinatown in New York!”
“There are lots of Chinese shops and restaurants there”.B.:Task 1:AB Unit1 exercise3
2:AB Unit 2 exercise1、2、4、5
3: Play a game: Students should prepare a piece of paper
第一課時(shí)
1、Warm up ⑴Greetings: T—Ss Ss—Ss
(a.)Student talk about there weekend: T: I bought some fruits, can you guess What did I buy? S:Did you buy…..2 Leading(1)A.Teacher show a peach(card)on the blackboard, “What can you see?” S: A peach.Teacher help the students say: There is a peach.(b.)Students make sentences with “ There is a …..”
(c.)Teacher show two peaches and teach “ There are …(n+s/es)”(d.)Students make sentences with “ There are …(n+s/es)” Watch POWERPOINT T: What?s this place?
S:(teacher writes the main structure on board as modal for other students)There is/are ….in/on….B.Game : The Six boxes
a.Students draw six big boxes on a piece of paper.b.Tell them to number the boxes ?1—6? c.Teacher ells what to draw in the boxes: In box 1 there is a pen.In box 2 there are two erasers.In box 3 there is an apple.In box…… C.Lead in
1)T: I describe a place, you guess.if you don?t know, you ask “ tell me more!” students guess out it?s Chinatown, teacher Show PPT about Chinatown.2)Ask students to describe with sentence structure “There be” given on the blackboard.3、Presentation(1)S open their books Question: Look at the pictures c.Who are they? d.Where are they? c.What are they doing? Student answer the questions.(2)listen to the tape(3)repeat after the tape.(4)Teacher explain the text and student practice the key points.a.The key points: miss
sometimes
restaurant
really
dancing
b.“ There is a …..”
“ There are …(n+s/es)”
(6)students practice to make sentences with the key points.Game:passing wordcards
make sentences
4、Drilling and Counselling(1)Finishing activity book exercise 3.(2)Students help each other.5、(Task-fulfilling)Guessing game:”Where do you go on weekend?” 6.Teachers handwriting:
There
is
a
(n)
There
are
(ns/es)
第二課時(shí)
Step1.Tell students a joke and give them a riddle to fun.Step2.Review the words: miss
sometimes
restaurant
really
dancing
Step3.Repeat the text after the tape, then students practice with partner in roles
Step4.Game a.Revise ?north? ?south? ?west? ?east? with the students.b.Tell the students to draw a big circle on a piece of paper.(tell them that the circle is an island and that you are going to describe the contents the island and and they have to draw the objects in the correct places.c.T:(draw a large island on your paper)In the north there is a river.In the south there are two mountains.In the west there are some trees.In the east there is a house.Step5.Homework: d.word dictation e.recite paragraph one f.Students make role play about unit one.Step6.課后反思
第三課時(shí)
Step1.a.Student make role play.b.Give words dictation.c.Open Activity Book.Step2.Do exercise 1.a.Play the recording again, then encourage them to tell the important things in the story.b.For each question invite a student to come to the blackboard and write the sentence.Step3.Do exercise 4.Look at the pictures.Write sentences.a.students draw things that they know how to say in English and be similar to the ones in the book.b.Collect all the pictures from the class.c.Students A and B, give A a picture , A describe the picture and B draw it.d.Show the picture, if student B draws the same object, he/she gets a point.Step4.Do exercise 3 Complete the dialogues a.Students look at pictures, tell what they can see on it.Students describe.b.According to the pictures and words in the brackets,students fill the blank
第2單元教案
Postcards from China
Teaching preparing 1.Teaching task Students book:Module2Unit 2Activity1, 2, 3 Teaching objects 2.
A.Basic task Key words:
bicycle mountain lake square Key sentences: “There are lots of bicycles in China” “There is a very famous river” B.Review:
The using way of the verb ?There be?
2.Use the structure to introduce famous places
For example: learn to use ?There be?
to describe some basic facts of a country or a place
3、Teaching point: Key words: bicycle mountain lake square
4、Teaching difficulty: How to pronounce? square.? How to use ?there be?
5、Task design: Learning task: Review words: miss
sometimes
restaurant
really
dancing
To learn words: bicycle
mountain
lake square
To learn “There are lots of bicycles in China” “There is a very famous river”
6、Teaching things: radio photo wordcards picture 7.課后反思
第二課時(shí)
1、Warm up ⑴Greetings: T—Ss Ss—Ss(2)Chant” America”
(3)Play a game to review the structure.2、Leading :(1)A.Watch PPT T: What?s this place?
S: It?s a picture of the Changjiang River.The Tian?anmen Square.The West Lake.The Huangshan Mountain
The Great Wall.a.Students learn to read them.b.Student describe them with “There is/are…..” B.Lead in
a.)Listen to the tape, and number the places.b.)Students repeat after the tape sentence by sentence.c.)Students try to recite the paragraph with teacher?s help, the students who have tried will get a sticker.3)Students practice with partner 3 Presentation:(1)Ss do exercise 2 Now point and say(2)Ss do exercise 3 Listen and repeat, pay attention to the stress.a.Play the tape and pause after the first sentence.b.Repeat the activity with various actions, e.g., standing up, waving arms…
4、Drilling and Counselling Learn the song: “There?s a Great Wall in China” a.Students listen to the tape.b.Students repeat
三.課后反思:
第五課時(shí)
Step1 Warm up:
Sing the song: “There?s a Great Wall in China”
Play a game:“Memory”
Rules: a.Students are divided into boys group and girls group.b.Give them limited time to memory the pictures, then they close the book.c.Students describe the objects in their memory, the more correct object they give, the more scores they will gain.Step2 Do activity book Activity 1 Listen and number.a.T: what can you see?
S: I can see there is/are…(Students try to describe the pictures)b.Teacher describe the pictures, students number.Step3
Activity 4 Look and complete the postcard.c.Ss draw the places with teacher?s describing.d.Ss write sentences, teacher offers help.Step4 Homework 1 Do exercise 3 2 words dictation.課后反思:
由于學(xué)生個(gè)體差異的不同,課堂上的內(nèi)容對(duì)有些孩子比較容易,而對(duì)個(gè)別學(xué)生來(lái)說(shuō)有很難,甚至不能聽(tīng)懂.但我是不會(huì)讓一個(gè)孩子落后的.六年級(jí)的內(nèi)容也增加了,教學(xué)內(nèi)容就要做合理的調(diào)整和補(bǔ)充,同時(shí)根據(jù)學(xué)生的心理特點(diǎn),有區(qū)別有重點(diǎn)的調(diào)整才行.《英語(yǔ)》六年級(jí)第七冊(cè)第3模塊
第1單元教案 Collecting stamp is my hobby
Teaching preparing: 1.Students book:Module3Unit 1Activity1, 2, 3 Teaching task: 2. Knowledge : A.Basic task: Key words:another collect
stamp
hobby
men
Key sentences: “I?ve got lots of stamps.”
“These are some stamps from Canada ”.“ This stamp is from China”
B.Review:
The using way of ?be from? 2. Make students talk about hobbies.3、Teaching point: Key words:
collect
stamp
hobby
men
women
another
4、Teaching difficulty: A.; men and man B;collect
5、Task design: A.Learning task:
To learn words: collect
stamp
hobby
men
women
another To learn the structure: “I?ve got lots of stamps.”
“These are some stamps from Canada ”.“This stamp is from China” B.To use the task: 1:AB Unit1 exercise 3 2:AB Unit2 exercise 1、2、4、5 3:You do action and I guess.4 : “Your hobby is doing….”
第一課時(shí)
1、Warm up ⑴Greetings: T—Ss Ss—Ss
(2)Game: you do action and I guess.(3)Write down the sentence: Your hobby is doing sth Exercise “Your hobby is….(3)Free talk: Student talk about their hobbies: T: My hobby is reading books, what?s your hobby?(My hobby is doing sth)S:My hobby is …..2、Leading :
(1)A.ask “What can you see? What?s this? ” S: It?s a stamp.T: What are these? S: These are some stamps.How to use :a stamp
and some stamps Teacher help the students say: This stamp is from….(b.)Students watch PPT and make sentences with “This stamp is from….” “These stamps are from…”
(c.)Teacher shows some stamps and teach “These stamps are from…”
(d.)Students make sentences with “These stamps are from…” B.Game : Guessing game Students watch PPT
T: What?s are these? S: These are stamps.Teacher give numbers to each stamp, then describe the picture of one of them, Students guess which number it is.T: This one has got a… on it.S: Number 3.Then reverse.C.Lead in T: Everyone has hobby, now listen to the tape , find out what Simon?s hobby is.3、(Presentation)(1)S open their books Question: Look at the pictures e.What?s Simon?s hobby? f.Where are the stamps from? c.Has Simon got any stamps from China? Student answer the questions.(2)listen to the tape(3)repeat after the tape.(4)Teacher explain the text and student practice the key points.a.The key points: collect
stamp
hobby
men
women
another b.Students practice to make sentences with the key points.c.Game:Passing wordcards make sentences
4、(Drilling and Counselling)(1)Finish SB U1 exercise3.(2)Pairwork.6.Teaching handwriting:
“This stamp is from….” “These stamps are from…”
三.課后反思:
第二課時(shí)
Step1.Game: Extend the sentence T: I?ve got lots of apples.S1: I?ve got lots of apples and bananas.S2: I?ve got lots of apples, bananas and pears.…….Step2.Review the words: collect
stamp
hobby
men
women
another
Step3.Repeat the text after the tape, then students practice with partner in roles
Step4.Talk about stamps(SB book activity 3)a.Number those stamps.b.Teacher describe one of the stamp with the main sentence structure given on the blackboard: “This stamp is from….”.“It has got …..on it”.Step5 Homework: g.word dictation h.recite paragraph one i.Students make role play about unit one.Step6.課后反思
第三課時(shí)
Step1.a.Students make role play.b.Give words dictation.c.Open Activity Book.Step2.Do exercise 1.e.Play the recording again, then encourage them to tell the important things in the story.f.Then, tell them to read the sentences in the exercise and decide if they are ?True?, ?False? or ?Don?t know?.(Explain that they should tick ?Don?t know? if the answer is not found in the dialogue.)
Step3.Do exercise 2.Now correct the false statements.Student A read the first false statement in Exercise1.Student B corrects.Step4.Do exercise 3 Complete the dialogues a.Students look at pictures, tell what they can see on it.Students describe.b.According to the pictures and words in the brackets, students fill the blank
Step5.課后反思
第2單元教案
I’ve got a hobby
Teaching preparing:
2、Studends book:Module2Unit 2Activity1, 2, 3
2、Teaching task: 2.Basic task:
To learn to speak the structure: “Have you got any dolls from Japan ” “Yes, I have./ No, I haven?t” B.Review: Grammer 2.Talking about your hobbies.3、Teaching difficulty: any/some
5、Task design: Review words: collect
stamp
hobby
men
women
another To learn “Have you got any dolls from Japan ” “Yes, I have./ No, I haven?t”
6、Teaching things: Radio
photo
picture
wordcards 第四課時(shí)
1、Warm up ⑴ Musical game “What?s your hobby?” “ My hobby is doing sth”(3)Watch PPT T: Students please watch PPT, What are these?
Can you guess what Miss Ma?s hobby is? S: Your hobby is flying kites.(PPT explains some kites and any kites)T: Yes, have you got any kites? “Yes, I have/ No, I haven?t” 2Leading :(1)A.Ask and answer T: Have you got any books? S1: Yes, I have/ No, I haven?t.Have you got any ….s? S2: Yes, I have/ No, I haven?t.Have you got any ….s? B.Practice a.)Go through all the pictures with the students to make sure that they know the vocabulary.2)Teacher write the main structure on the board: “Have you got any…..” “Yes, I have./ No, I haven?t” 3)Students practice with partner
3、Presentation: Ss do exercise 3 Listen and repeat, pay attention to the stress.a.Play the tape and pause after the first sentence.b.Repeat the activity with various actions, e.g., standing up, waving arms…
4、Drilling and Counselling Learn the chant: “HOBBY” a.Students listen to the tape.b.Students repeat
第五課時(shí)(REVIEW)Step1 Warm up:
Sing the song: “HOBBY”
Step2 Do activity book Activity 1 Listen and answer the questions.Step3
Activity 3 Answer the questions.a.Students complete the questions according to their own situation.b.Students work in pairs:
A keeps the book open and asks questions B closes his book and answer A?s questions.c.They exchange the roles.Step4 Homework e.Do exercise 3 f.words dictation.課后反思:
本單元的內(nèi)容涉及到 my hobby(我的愛(ài)好),讓孩子準(zhǔn)備的課堂用具孩子沒(méi)能做充分的準(zhǔn)備.因此在課堂上孩子們談?wù)撜f(shuō)的時(shí)間就縮短了.另外重點(diǎn)句型的操練,孩子們也很快的領(lǐng)會(huì)了.Module Four Happy Thanksgiving!
Teaching preparin 1. Student book:Module1Unit 1Activity1, 2, 3
2、Teaching task: 2.Basic task: Key words: festival
special
meal
sound Key sentences:
“What do you do on …..”
“Thanksgiving is my favorite festival.”
“We say ?thank-you? for our food, family and friends.”
C.Review: “Can you tell me more about…..”and“… is my …”
3、Teaching point: Words : festival
special
meal
sound
4、Teaching difficulty festival sound “Thanksgiving is my favorite festival.” “We always have a special meal.”
5、Task design:
To learn words :festival
special
meal
sound
To learn sentences: “What do you do on …..” “Thanksgiving is my favorite festival.” “We always have a special meal.”
“We say ?thank-you? for our food, family and friends.”
1:SB Unit 1 exercise2、3
2: AB Unit 1exercise 1、2、3、4、5
6、Teaching things radio photo wordcards picture
第一課時(shí)
1、Warm up ⑴ Sing a song “We wish you a merry Christmas.” Competition: List festivals as many as possible.2 Leading :(1)a.(Watch PPT— pictures about Chinese festivals)Ask questions: “what is this festival?”
“What do we do at that festival?” b.Then show the PPT of main sentence structures: “… is my favorite festival, we always do(something)”
Students look at pictures and talk about festivals in pairs with the main structures offered.c.Students show there ideas with their partner.B.Lead in
1)T: You know much about Chinese festival, how many western festival do you know? Students list the western festivals.T: Very nice!Today Simon will tell us more about American festival, listen to the tape and later you must tell me about them.3、Presentation:(1)S open their books Question: Look at the pictures a.Who are they? b.What can you see? Students answer the questions.(2)Give the questions: “What are the two American festivals in the story?” “What do people do on Flag Day?” “What do people do on Thanksgiving Day?”(3)Answer the questions.4、Drilling and Counselling(1)Game: Guessing(T vs Ss)a.Prepare three word cards: Thanksgiving Day
Flag Day
Christmas Day b.Teach them to read.c.Teacher describes the activities that people do in different festival.T: You can see Christmas trees.Ss: Christmas Day 6.Homework: a.Write the new words.b.Collect Chinese and American festival information.第二課時(shí)
Step1.Game: Guessing(Ss1 vs Ss2):
Repeat the text after the tape, then students practice with partner in roles.Step2 Discussion
Step3.Students make role plays about western festivals with their partner.Step4.Homework: a.word dictation b.recite paragraph two
: 第三課時(shí)
Step1.Give words dictation
Step2.Open Activity Book, do exercise 1: Listen to the story again and tick or cross.a.Students read the questions.b.Students look at pictures, tell what they can see on it.Students describe.c.Teacher gives help, students finish the question.d.Play the tape, students finish the exercise.Step3.Do exercise3.Complete the table.a.Review “ I,me,we,our” b.Complete the table
Step4.Do exercise Write about Spring Festival.a.Students look at pictures, tell what they can see on it.Students describe.Ss: Watch TV Talk with each other.Play games.Lesson four
What’s your favorite festival?
1、Teaching preparing:
Teaching task: Student book: Module1Unit 2Activity1, 2, 3
2、Teaching task :
Basic task:
Key words:lantern
race
moon cake
Key sentences: “What?s your favorite festival?”
“My favorite festival is ……” 3
Teaching point: :
Lantern Festival
Spring Festival
Mid-Autumn Festival Dragon Boat Festival
race
moon cake “What?s your favorite festival?”
“My favorite festival is ……”
4、Teaching : lantern, moon
5、Task design: To learn words :
festival
special
meal
sound To learn sentences: Lantern Festival
Spring Festival
Mid-Autumn Festival
Dragon Boat Festival
race
moon cake
二、1、Warm up ⑴Greetings: T—Ss
Ss—Ss(2)Do the chant, review “I, me, we, our”(3)Play a matching game:
Thanksgiving Day
Sing flag song
Flag Day
Receive presents
Christmas Day
Cheat each other
Ask volunteers to finish the matching.(4)Ask students to add more activities.2、導(dǎo)入(Leading)(1)A.1Watch PPT
T: What?s this festival? S: It?s ……
Students learn to read Lantern Festival
Spring Festival
Mid-Autumn Festival
Dragon Boat Festival B.Game: Guessing game
T:(mimes rowing a boat)S: Is it Dragon Boat Festival? T: Right!b.Students do practice in pairs: choose a festival, ask and guess.3、Presentation:(1)S open their books(2)listen to the tape
(3)Replay sentence by sentence(4)Students repeat after each sentence.(5)Students try to recite one of the festival.4、Drilling and Counselling StudentA chooses a festival, studentB asks and if he or she can?t guess out, he can ask “Tell me more.” unless he got the answer.第五課時(shí)
Step1 Warm up: Play a game:“Sentence passing”
Rules: Students ask and answer one to the next to review:
“What?s your favorite festival?”“My favorite festival is ……”
Step2 Do activity 3.Listen and repeat, pay attention to the stress.a.Play the tape and pause after the first sentence.b.Repeat the activity with various actions, e.g., standing up, waving arms…
Step3 Do Activity Book Activity 1 Listen and complete the sentences.a.T show many pictures, if they like the picture they stand up and teacher count: “X students like…”;if they don?t like they remain seated.a.Ss read the questions with teacher?s help.b.Ss write sentences, teacher offers help
Homework 1.Do exercise 4 2.words dictation.課后反思:
通過(guò)對(duì)本單元的小測(cè)驗(yàn),孩子們對(duì)這節(jié)課的知識(shí)掌握的還不錯(cuò).孩子們也已經(jīng)知道了外國(guó)節(jié)日和中國(guó)節(jié)日不同.有的孩子上網(wǎng)查了許多關(guān)于節(jié)日的資料,在班里和其他的孩子一起分享.