三、作出速度-時(shí)間圖像(v-t圖像)1、確定運(yùn)動(dòng)規(guī)律最好辦法是作v-t圖像,這樣能更好地顯現(xiàn)物體的運(yùn)動(dòng)規(guī)律。2、x y x1 x2 y2 y1 0討論如何在本次實(shí)驗(yàn)中描點(diǎn)、連線。(以時(shí)間t為橫軸,速度v為縱軸,建立坐標(biāo)系,選擇合適的標(biāo)度,把剛才所填表格中的各點(diǎn)在速度-時(shí)間坐標(biāo)系中描出。注意觀察和思考你所描畫的這些點(diǎn)的分布規(guī)律,你會(huì)發(fā)現(xiàn)這些點(diǎn)大致落在同一條直線上,所以不能用折線連接,而用一根直線連接,還要注意連線兩側(cè)的點(diǎn)數(shù)要大致相同。)3、若出現(xiàn)了個(gè)別明顯偏離絕大部分點(diǎn)所在直線的點(diǎn),該如何處理?(對(duì)于個(gè)別明顯偏離絕大部分點(diǎn)所在直線的點(diǎn),我們可以認(rèn)為是測(cè)量誤差過大、是測(cè)量中出現(xiàn)差錯(cuò)所致,將它視為無效點(diǎn),但是在圖像當(dāng)中仍應(yīng)該保留,因?yàn)槲覀円鹬貙?shí)驗(yàn)事實(shí),這畢竟是我們的第一手資料,是原始數(shù)據(jù)。)4、怎樣根據(jù)所畫的v-t圖像求加速度?(從所畫的圖像中取兩個(gè)點(diǎn),找到它們的縱、橫坐標(biāo)(t1,v1)、(t2,v2),然后代入公式,求得加速度,也就是直線的斜率。在平面直角坐標(biāo)系中,直線的斜率
當(dāng)代社會(huì)生活的變化比以往任何時(shí)代都要快。語(yǔ)言尤其是詞匯記錄了這些發(fā)展變化,因而也涌現(xiàn)了大量的新詞新語(yǔ)。據(jù)統(tǒng)計(jì),近幾年每年大約要出現(xiàn)1000個(gè)左右的新詞新語(yǔ),而字典、詞典的多次修訂、增補(bǔ)就反映了這種情況。但相對(duì)來說,也有一些流行語(yǔ)又逐漸受到冷遇,甚至退隱。為了更好的對(duì)新詞新語(yǔ)與流行文化作一番檢視與探究,那讓我們考察一下它們是怎么產(chǎn)生的吧?老師先給同學(xué)們列舉四種途徑:大屏幕3。同學(xué)們能再舉出以上途徑的一些例子嗎?老師列舉(4)其實(shí)不只這些,那還有哪些途徑呢?找同學(xué)說并舉例。說的非常好,請(qǐng)同學(xué)們看老師的例子,總結(jié)(5)。從新詞新語(yǔ)的產(chǎn)生途徑可以看出,這些鮮活得像畫一樣的新詞就是這個(gè)時(shí)代跳動(dòng)的血小板,它涉及當(dāng)代社會(huì)的重大事件、現(xiàn)象與時(shí)弊,以及人們?nèi)粘I畹母鱾€(gè)層面如人生意義、生活方式、愛情、友情、就業(yè)、消費(fèi)、時(shí)尚等,時(shí)代性強(qiáng),傳播面廣,反映著當(dāng)代社會(huì)時(shí)局與人們文化心態(tài)的變化。
(3)內(nèi)陸和中西部城鎮(zhèn)主要以煤和火電為主;廣大農(nóng)村和邊遠(yuǎn)地區(qū)大多正從使用農(nóng)作物秸稈等生物能源。(4)人均能源資源不足。我國(guó)是世界第三大能源生產(chǎn)國(guó)和第二大能源消費(fèi)國(guó),而我國(guó)能源短缺,特別是油氣資源短缺已成為制約我國(guó)經(jīng)濟(jì)發(fā)展的重要因素。相關(guān)數(shù)據(jù)——煤炭、石油和天然氣的人均資源占有量只有95t,世界平均值為209t,約是世界人均值的1/2;我國(guó)人均石油可采儲(chǔ)量3t,世界平均值為28t,約為世界平均值的1/10。我國(guó)人均能源消費(fèi)量不足1.2噸標(biāo)準(zhǔn)煤,居世界89位,不足世界人均能源消費(fèi)水平的一半,僅占發(fā)達(dá)國(guó)家的1/5~1/10。其中人均消費(fèi)650kg標(biāo)準(zhǔn)煤,是世界平均額的95%;人均消費(fèi)石油相當(dāng)145kg標(biāo)準(zhǔn)煤,為世界平均數(shù)的16.8%;人均消費(fèi)天然氣相當(dāng)17.7kg標(biāo)準(zhǔn)煤,為世界平均數(shù)的3.9%;人均消費(fèi)電力501.5kWh,為世界平均水平的25%。(5)是能源消費(fèi)結(jié)構(gòu)不合理,突出存在著一低兩高:即電能消費(fèi)比例低,非商品生物能源消費(fèi)量高,一次性商品能源消費(fèi)中原煤消費(fèi)比重高。原煤消費(fèi)達(dá)到75%,遠(yuǎn)高于26.2%的世界平均水平。
共享實(shí)驗(yàn)收集的信息,分享實(shí)驗(yàn)探究的結(jié)論,體驗(yàn)收獲的樂趣。 小結(jié)拓展 這節(jié)課由大家感興趣的球類運(yùn)動(dòng)和彈弓游戲,提出了功與速度變化關(guān)系的問題,利用倍增思想解決測(cè)量對(duì)物體做功的問題,使用我們熟悉的器材設(shè)計(jì)了探究方案,并進(jìn)行實(shí)驗(yàn)探究,采用圖像法進(jìn)行數(shù)據(jù)處理,初步得出W∝V2的關(guān)系。在我們這節(jié)課探究以前,科學(xué)家就通過試驗(yàn)和理論的方法,已經(jīng)總結(jié)出了功與速度變化的定量關(guān)系。人類社會(huì)也在社會(huì)生活和生產(chǎn)的各個(gè)領(lǐng)域予以利用。比如,古代的戰(zhàn)爭(zhēng)武器拋石器、大型弓弩,以及現(xiàn)代飛機(jī)彈射系統(tǒng)、還有機(jī)器人行走等等,希望同學(xué)在今后的學(xué)習(xí)中注意留心生活中的物理和社會(huì)中的物理。 領(lǐng)會(huì)總結(jié)。培養(yǎng)概括總結(jié)的能力,進(jìn)一步鞏固、感悟、提升實(shí)驗(yàn)探究中獲得的思維能力及動(dòng)手能力。感悟社會(huì)中的物理,認(rèn)識(shí)物理學(xué)對(duì)科技進(jìn)步以及文化和社會(huì)發(fā)展的影響。 列舉學(xué)生知道的社會(huì)中做功使物體速度變化的例子,增強(qiáng)學(xué)生將物理知識(shí)應(yīng)用于生活和生產(chǎn)的意識(shí),培養(yǎng)學(xué)生的社會(huì)參與意識(shí)和對(duì)社會(huì)負(fù)責(zé)任的態(tài)度。
一、說教材(一)教材分析本課所介紹的新文化運(yùn)動(dòng),是繼上一節(jié)所學(xué)的《西學(xué)東漸和維新變法思想》之后中國(guó)另一波影響巨大的思想解放潮流,旨在向西方學(xué)習(xí)、尋求強(qiáng)國(guó)御侮之道。在整個(gè)知識(shí)體系中,它既是資產(chǎn)階級(jí)領(lǐng)導(dǎo)的舊民主主義革命的補(bǔ)課,又是無產(chǎn)階級(jí)領(lǐng)導(dǎo)的新民主主義革命的序曲。它所帶來的思想的空前解放,也就為馬克思主義的傳播創(chuàng)造了條件,為中共的成立奠定基礎(chǔ)。這一課的學(xué)習(xí)能讓學(xué)生清晰認(rèn)識(shí)新文化運(yùn)動(dòng)和馬克思主義在近代中國(guó)思想解放歷程中的重要作用和巨大影響。與必修一和必修二政治經(jīng)濟(jì)史的結(jié)合也能讓使學(xué)生強(qiáng)化歷史聯(lián)系。新課程標(biāo)準(zhǔn)對(duì)本課就做了明確的規(guī)定:1、概述新文化運(yùn)動(dòng)的主要內(nèi)容,探討其對(duì)近代中國(guó)思想解放的影響。2、簡(jiǎn)述馬克思主義在中國(guó)傳播的史實(shí),認(rèn)識(shí)馬克思主義對(duì)中國(guó)歷史發(fā)展的重大意義。根據(jù)課標(biāo)要求,我制定了以下具體的三維目標(biāo)。
Textbook: Senior English for China (Book 4), by Liu Daoyi Time Allotment: 1 period (40 minutes)Date: March 20, 2014Teaching aids: blackboard, Multi-media, Power Point, chalk I. Text Analysis (教材分析)This unit is about body language, and the text selected in the reading part demonstrates the difference and similarity of body language in many parts of the world. Through learning this passage, students are required to raise their awareness of using body language in different parts of the world. As body language is closely related to our daily life, it is easy to arouse students’ interest in learning this text. Reading skills and speaking training are designed around the text.II. Teaching Objectives (教學(xué)目標(biāo))By the end of the lesson, students will be able to:1. Language Skill Objective(語(yǔ)言技能目標(biāo)): develop reading ability (skimming and scanning)as well as speaking ability.2. Cultural Knowledge Objective(文化知識(shí)目標(biāo)): know about the cultural differences of using body language.3. Affective Objective(情感目標(biāo)): increase students’ awareness of using body language correctly in different cultures. III.Teaching Focuses and Difficulties(教學(xué)重點(diǎn)和難點(diǎn))1. Teaching Focuses(教學(xué)重點(diǎn)): the difference and similarity of body language in many parts of the world.2. Teaching Difficulties(教學(xué)難點(diǎn)): develop students’ reading abilities of skimming and scanning and ask the students to show their opinions with fluent English.
Good morning, distinguished judges:It’s my honor to talk about my teaching ideas with you. Today my topic is Women of Achievement. My presentation consists of six parts: the analysis of teaching material and student, teaching aims, key and difficult points, teaching and studying method, teaching procedures and blackboard design.First, let’s focus on the analysis of teaching material. This lesson is from New Senior English for China Student’s Book 4 Unit 1, the reading part. The main topic of the passage is the introduction of a student of Africanwildlife. After this lesson, the students will learn more information about her studying chimps in Africa, and their reading and speaking abilities can be developed as well.The next part is the analysis of students. My students are in senior high students. They have learnt English for many years, they’ve known many words and sentences, but their speaking and reading abilities are still not very good. So I will practice their speaking and reading abilities through different exercises.According to the New Standard Curriculum and the present situation, I set the teaching aims as follows: firstly, knowledge aims. Students can grasp some new words, such as worthwhile, move off. Moreover, students can understand the content of the passage and get familiar with the topic of studying chimps in wildlife. Secondly, ability aims. Students can use reading strategies such as skimming and scanning in reading process. Thirdly, emotional aims. Students can have the awareness of protecting animals and care about animals.Based on the above analysis, the key point of this lesson is to get the main idea and the detailed information from the passage; the difficult point is to talk about the wildlife protection and use reading strategies.
The oldest and the most popular park in the worldenjoy the exciting activities thereget close to the life-size cartoon characters like Mickey Mouse and Donald Duck Step 3 Pre-reading1.What do you suppose a theme park is ?2.What do you think you can see in a theme park?(1.It is a kind of amusement park which has a certain theme – that the whole park is based on. 2.buildings, castles, statues, rare animals and birds, and so on.) Step 4 Reading ----- Theme Parks –---- Fun and More Than Fun1.Predict : Read the title and the pictures on P. 34 and PredictWhat is the meaning of the title “Theme Park – Fun and more than fun”?(The title means that theme parks are fun to visit, but that they can also be educational and can offer useful information.)2.Skimming Fast read and answer:What activities can we take in a theme park?Amusement park: Bumper car Merry-go-round slide bungee jumping Free-fall rides Horror films Pirate ship Ferris wheel roller coaster3.Scanning Read again and you will find various theme parks are mentioned in the passage . Then what are they ?Theme parks: Sports theme park History theme park Culture theme park Marine or Ocean theme Park Future park Science theme park Disneyland4.Careful reading and find the main idea of each paragraph:THEME PARKS---- entertaining/ educationalPara.1 Traditional parks are places to go for relaxation and to have time away from our busy lives.Para.2 Theme parks are different They’re large and full of things to do, see and buy.Para.3 Theme parks are built around a single idea or theme. One example is a sports park.Para.4 Another kind of theme park is historical more and cultural and can be educational.Para.5 Disneylandwas the first theme park. It is based on the fantasy life and characters of Disney’s films.Para.6 Some examples of educational theme parks include sea world parks and science parks.
通過寫文章梗概,培養(yǎng)學(xué)生綜合運(yùn)用語(yǔ)言的能力,學(xué)習(xí)用恰當(dāng)?shù)挠⒄Z(yǔ)描述科學(xué)家的故事。這是本課的教學(xué)難點(diǎn)。教師可以使用完形填空的方式來幫助學(xué)生整理語(yǔ)篇,從而來降低難度。本課的教學(xué)重點(diǎn)的突破方法是:在閱讀前,讓學(xué)生初步了解得出科學(xué)觀點(diǎn)所需要的基本程序,從而輕松而自然地導(dǎo)入文章的閱讀;在閱讀過程中,由易到難設(shè)計(jì)快速閱讀和精讀的問題,層層推進(jìn)各種閱讀活動(dòng),讓學(xué)生對(duì)閱讀內(nèi)容從整體感知到細(xì)節(jié)理解,最后深層讀懂整篇文章,同時(shí)加強(qiáng)閱讀策略的指導(dǎo),讓每個(gè)學(xué)生都主動(dòng)參與課堂教學(xué)活動(dòng),最終達(dá)到提高閱讀能力的目的。Step 4 Post-readingGroup Activities四人小組共同合作,在老師的適當(dāng)指導(dǎo)下,就以下2個(gè)問題展開討論,讓學(xué)生就所知、所學(xué)、所感和所想融入話題,然后抽若干同學(xué)代表作小組發(fā)言。1. What do you think about John Snow, and what should we learn from him?2. Cholera was 19th century disease, which two diseases are similar to cholera today? Why?
今天我們來介紹一下必修五第四單元的授課方式。這個(gè)單元的題目是Making the news。應(yīng)該是學(xué)生比較感興趣的話題,學(xué)生往往對(duì)新聞工作充滿好奇,所以我們可以利用這個(gè)機(jī)會(huì)多設(shè)計(jì)一些師生互動(dòng)和學(xué)生互動(dòng),來激發(fā)起學(xué)習(xí)的積極性,提高學(xué)習(xí)效率。同時(shí)我們可以利用這個(gè)單元不僅幫助學(xué)生掌握語(yǔ)言知識(shí),培養(yǎng)語(yǔ)言能力,同時(shí)讓其了解新聞工作的重要性,培養(yǎng)起社會(huì)智能感。這個(gè)單元分為六個(gè)課時(shí),它的教學(xué)目標(biāo)是這樣的:語(yǔ)言目標(biāo)是掌握詞匯表中的常用單詞和短語(yǔ),掌握倒裝句的一些基本用法。 技能目標(biāo)是能初步掌握約會(huì)的基本句型并在真實(shí)的場(chǎng)景下正確運(yùn)用。新聞報(bào)道類文章的寫作技能。采訪的基本規(guī)范和溝通技能。情感目標(biāo)是對(duì)新聞報(bào)道的客觀性和真實(shí)性有更好的理解。對(duì)新聞?dòng)浾叩穆殬I(yè)有更深入的了解,并能體會(huì)其工作的重要性。下面我們來介紹一下第一課時(shí)的授課方式,第一課的教學(xué)目標(biāo)是這樣的第一課時(shí)的教學(xué)目標(biāo)語(yǔ)言目標(biāo):單詞:Occupation, journalist, editor, photographer, curious, personality, enthusiasm
Then I would ask them to think of a funny English or Chinese and tell it to partners. While telling stories, they can use expressions and some acting to help make the story funny. 5 minutes would be given to do this.Those stories they told there will be the material for their writing. Soletting them tell it at first is helpful. And they can make a difference between telling a funny story and writing it down. Generally speaking, it is difficult forstudents to write well because they don’t know what to write and how to write. Asking them to tell their own stories at first can help them come up with what to write.After their telling, I would invite someone to share his/her story with all of us and I would write it down on the blackboard.This example story would be used as a sample to illustrate the format of funny story. Different from a story from teacher or textbook, a story from students can obviously become a interesting material to draw students’ attention.Then I would ask the whole class to put this story into several parts. It might be a little bit difficult for them. So I would ask them to find out whether all the sentences are necessary. After delete some sentences, there are 6 sentences left behind. Then they can easily put them into three parts. After interaction with students, I would teach them the right terms for each part and conclude the format of funny story.This step is the key and difficult point in my lesson. So I mainly usetask-based teaching method in this part and the task for students was divided into several stages. With the separated difficult level, students can find there are usually three parts in writing. They can also learn to write without the unnecessary parts in the process of analyzing. And then I wouldn’t rush to tell them the right terms to them directly. Instead, I would ask them to name them by their own. A confused mind is better for acquiring knowledge.While-writing:Then I would give students 7 minutes to write down this story, without other requirements.With all the preparations in pre-writing, students’ difficulties were cleared. So it would be much easier for them to write down the story within 7 minutes. There are no other requirements because students’ first writing is actually a drafting. It would be revise and edit several times later. Writing, as a skill
Good afternoon, teachers, It’s my great pleasure to be here sharing my lesson with you.The content of my lesson is Senior English Book 3 Unit 5 Canada —— “The true North”.I’ll be ready to begin this lesson from five parts. Analysis of the teaching material,the teaching methods,the studying methods, the teaching procedure,and Blackboard design.First, let me talk about the teaching material.Part 1 Teaching Material:This unit is about the introduction of Canada. By studying of this unit,we’ll enable the students to learn the geography, population, main cities, and natural beauty, natural resources of Canada. Through the training of the unit, it also requires students to learn some Language skills such as the expressions of position and emotions.So it plays an important part in the English teaching in this book.After studying the teaching material and analyzing the rule of children’s growing of mind,I think the teaching aims are the followings:1.Knowledge objects:(1) make the students learn some new words and phrases(2) make the students understand the content of the lesson.2.Ability objects:(1)To develop the Ss’ abilities of listening, speaking, reading and writing. Especially reading and speaking ability.(2) learn to talk about the characters of Canada in English(3)To train the Ss’ ability of working in pairs.3.Emotion objects:(1)Enable students to understand the characters of Canada..(2)Stimulate Ss to work hard to make China stronger.Part 2 Teaching Methods:I think helping students learn to master new words and phrases and improve the students’ reading and speaking ability is import and the difficult.According to the analysis of the teaching material and the import points and the difficult points,I will use the following teaching methods : question-guiding approach; fast-reading and careful reading; multi-media teaching methods; discussion
Language learning needs a context, which can help the learners to understand the language and then can product comprehensible output, so computer has the advantages to make the materials attractive.Part 3 Learning MethodsTask-based, self-dependent and cooperative learningPart 4 Teaching ProcedureStep One Lead-in“Interest is the best teacher.” Therefore, at the very beginning of the class, I should spark the students’ mind to focus on the centre topic “the band”. I’ll show some pictures of food to attract their attention and then bring some questions.Question:What kind of food they like?What should go into a good meal?The answers must relate to the diet. After this, the students will be eager to know something about a balance diet and this is the very time to naturally lead the class into Step 2Step 2 Reading for information: skimming and scanning In this step, I use Task-based Language Teaching method, which can give students a clear and specific purpose while skimming and scanning the context.Task 1 General ideaThe students will be asked to just glance at the title and the pictures of the passage, and then guess what they will read in the text. And they’ll be divided into groups of four to have a discussion.The purpose is to inspire the students to read actively, not passively. In addition, the task is to develop the students’ reading skill by making prediction and to encourage the students to express their thoughts in English and cooperate with each other.Task 2 Main idea of each paragraphCooperative learning can raise the students’ interest and create an atmosphere of achievement. Based on this theory, I divide the whole class into 4 groups to skim the whole text and get the main idea of each paragraph.
Knowledge objectives:(1) to make Ss grasp the usage of words, expressions and sentence structures: statistics, struggle, thanks to, rid of, some patterns for persuasion, the “ing” form as subject and object;(2)to use learnt knowledge to persuade sb.Ability objectives:(1) to develop Ss’ reading skills(skimming, scanning, word guessing);(2) to improve Ss’ speaking, communicating and cooperating skills.Emotional objectives:to make Ss know the contribution of Yuan,and learn his spirit and his simple life time.Teaching important and difficult points:(1) some words, expressions and sentence structures mentioned above;(2)the content of the text;(3)training their reading and speaking skills.Teaching methods: CLT, TBLT,QT.Learning strategies: CLS, QLS, TBLS.Teaching procedures:Step 1 lead-in: (1) teacher plays a piece of recent news from CCTV about the harvest of the super hybrid rice, and ask students whether they know Yuan or not, and talk about him and his contribution.(2)Brain storm: let Ss describe Yuan in their minds including his appearance, his living condition and so on.Step 2 fast reading tasks:(1)teacher introduces Yuan and super hybrid rice(2)make Ss read the text as fast as possible with questions. Such as: what’s the general ideaof this passage? What’s Yuan’ dream? (skimming and scanning skill)Step 3 intensive reading tasks(1)let Ss read the text silently, find topic sentence of each paragraph and draw the difficult sentences and the knowledge what they don’t understand.(words guessing)(2)teacher and Ss talk about the important words, expressions and sentences together, and ask Ss to retell the content of the text.(summarizing and paraphrasing)(3)teacher summarize this part.(4) read again following the courseware.
Teaching Aims:Knowledge 1. Get the students to learn the useful new words and expressions in this section. Aims:2. Let the students learn about how the UK was formed and the four groups of invaders.1. Develop students’ reading ability and let them learn different Ability reading skills. Aims:2. Enable students to learn to talk about the United Kingdom and the Union Jack Emotional 1. Let students know more about the UK2. Develop students’ sense of cooperative learning Aims:Teaching Important Points:1. Let the students learn about the countries of the United Kingdom and the Union Jack2. Get the students to read the passage and know about how the UK was formed and the four groups of invaders.3. Have the students learn different reading skills.Teaching Difficult Ponts:1. Develop students’ reading ability.2. Enable students to talk about the United Kingdom and the Union Jack.3. Let students learn how the UK was formed geographically and historically.Teaching Methods:Showing pictures, asking, exercising, listening, reading etc.Teaching Aids:A computer,a projector and a blackboard.Teaching Procedures: 1) Show a map of the world, ask students the following questions:Where is the UK?What’s the full name of the UK?2) Ask the students work in pairs to do the quiz on Page 9.Do you want to test how many things you know about the United Kingdom? Let’s have a small test.Using the map on P9, students answer the following questions:?How many countries does the UK consist of? What are they??England is divided into three main areas. Do you know what they are? 1) Scanning (10Minutes )Let the students hold the questions asked in pre-reading and read the passagequickly and then let them do the following exercise.Join lines to the right answer.
3、清代的“閉關(guān)鎖國(guó)”政策:(1)原因:①根本原因:自給自足的封建自然經(jīng)濟(jì);②客觀原因:西方殖民者向東方殖民擴(kuò)張;③直接原因:對(duì)付東南沿海人民的抗清斗爭(zhēng)(2)內(nèi)容:嚴(yán)格限制對(duì)外貿(mào)易。但并不是禁絕海外貿(mào)易??滴跬砥?,禁止商人前往南洋貿(mào)易;乾隆時(shí)只開廣州一處通商,并設(shè)立政府特許的貿(mào)易機(jī)構(gòu)廣州“十三行”統(tǒng)一經(jīng)營(yíng)管理對(duì)外貿(mào)易。(3)后果:①閉關(guān)鎖國(guó)政策妨礙了海外市場(chǎng)的開拓,抑制了資本的原始積累,從而阻礙了資本主義萌芽的發(fā)展。②閉關(guān)鎖國(guó)政策隔絕了中國(guó)與外界的聯(lián)系,從而阻斷了中國(guó)學(xué)習(xí)西方的先進(jìn)科學(xué)技術(shù),阻礙了生產(chǎn)力發(fā)展,使中國(guó)落后于世界潮流。③“閉關(guān)鎖國(guó)”政策在一定程度上也保護(hù)了國(guó)家的安全。教師可以設(shè)置問題:17-18世紀(jì)中國(guó)顯露出哪些危機(jī)?
通過這個(gè)示例呢,我們可以得到解決向心力問題的一般的步驟,確定對(duì)象,找出軌跡,找出圓心,然后進(jìn)行受力分析,讓同學(xué)們參考這樣的步驟,逐步的解決圓周運(yùn)動(dòng)的問題,對(duì)于變速圓周運(yùn)動(dòng),我通過鏈球運(yùn)動(dòng)進(jìn)行引入,這里是一個(gè)鏈球運(yùn)動(dòng)的視頻,在同學(xué)們觀看視頻之前,我給同學(xué)們提出問題,鏈球收到繩子的拉力,做的是勻速圓周運(yùn)動(dòng)嗎? 然后再課堂上我們?cè)僮鲆粋€(gè)小實(shí)驗(yàn), 我們可以通過改變拉線的方式來調(diào)節(jié)小球的速度大小嗎? 那么對(duì)小球,做加速圓周運(yùn)動(dòng),進(jìn)行受力分析,我們可以看到,小球做加速運(yùn)動(dòng)時(shí),他所受到的力,并不是嚴(yán)格通過軌跡的圓心,在進(jìn)行分析的時(shí)候,特別強(qiáng)調(diào),小桶所受力的切線方向分力,和法線方向分力,切線方向分力,改變小球運(yùn)動(dòng)速度大小,法線方向分力,改變了小球運(yùn)動(dòng)的方向,法線方向的分力,在這里就是向心力,產(chǎn)生了向心加速度,通過這樣一個(gè)例子進(jìn)行分析,同學(xué)們是比較容易理解的,
基于以上分析,為使本堂課圍繞重點(diǎn)、突破難點(diǎn),同時(shí)讓學(xué)生在課堂教學(xué)中能力得到提高,我設(shè)計(jì)如下教學(xué)過程。(一)創(chuàng)設(shè)情景認(rèn)識(shí)形變由同學(xué)們已有的形變知識(shí)入手,引入新課。教師演示:①?gòu)椈傻膲嚎s形變;②彈簧的拉伸形變③視頻播放:竹竿形變、鋼絲的扭轉(zhuǎn)形變。得出形變的概念及各類形變。[設(shè)計(jì)意圖:我從生活情景中引入新課,是為了激發(fā)學(xué)生的好奇心,為學(xué)生學(xué)習(xí)重點(diǎn)和難點(diǎn)內(nèi)容作鋪墊。]設(shè)問:摩天大樓在風(fēng)的吹拂下會(huì)不會(huì)擺動(dòng),發(fā)生形變嗎?演示微小形變放大實(shí)驗(yàn):由于這種形變不容易觀察,會(huì)使學(xué)生產(chǎn)生疑問:到底有沒有發(fā)生形變?解決的辦法是微小形變的演示實(shí)驗(yàn)。為什么光點(diǎn)會(huì)往下移?讓學(xué)生帶著問題思考后得出結(jié)論:是由于桌面發(fā)生了形變,但是形變不明顯。為后面解決壓力和支持力都是彈力做好鋪墊。[設(shè)計(jì)意圖:使學(xué)生知道“放大”是一種科學(xué)探究的方法。]
本節(jié)課是人教社物理必修1第三章第三節(jié)的內(nèi)容,編排在彈力之后。該節(jié)知識(shí)既是力學(xué)的基礎(chǔ),也是組成整個(gè)高中物理知識(shí)的一塊“基石”,所以這節(jié)內(nèi)容的教學(xué)如何引領(lǐng)學(xué)生自主積極地探究摩擦力產(chǎn)生的條件和影響因素,體驗(yàn)?zāi)Σ亮μ攸c(diǎn)規(guī)律的發(fā)生過程是本節(jié)課的重點(diǎn),應(yīng)高度重視本節(jié)教學(xué)過程;由于摩擦力問題的復(fù)雜性,且在具體問題中又表現(xiàn)出“動(dòng)中有靜,靜中有動(dòng)”,尤其靜摩擦在許多情形下似乎又是“若有若無,方向不定”,因此,對(duì)于初學(xué)者也是有一定難度的。也正是由于教材內(nèi)容的上述特點(diǎn),本節(jié)課又易于激起學(xué)生的求知欲,易于培養(yǎng)學(xué)生的辯證觀點(diǎn),易于錘煉學(xué)生的物理素質(zhì)。要充分用好該節(jié)教材內(nèi)容,深入挖掘知識(shí)間的有機(jī)聯(lián)系,對(duì)學(xué)生開展針對(duì)性的思維訓(xùn)練,進(jìn)而提高學(xué)生應(yīng)用物理知識(shí)解決實(shí)際問題的能力和創(chuàng)新思維能力。高中物理《課標(biāo)》對(duì)該知識(shí)點(diǎn)的要求是,“通過實(shí)驗(yàn)認(rèn)識(shí)滑動(dòng)摩擦、靜摩擦的規(guī)律,能用動(dòng)摩擦因數(shù)計(jì)算摩擦力”。其中,對(duì)靜摩擦力規(guī)律的認(rèn)識(shí)應(yīng)該包括最大靜摩擦力。
(一)、復(fù)習(xí)提問1、請(qǐng)說出功的計(jì)算公式及功的單位2、我們用哪個(gè)物理量表示物體運(yùn)動(dòng)的快慢?(二)、創(chuàng)設(shè)情景,引入新課1、播放多媒體素材,用起重機(jī)和一個(gè)工人搬運(yùn)幾百塊磚比較哪一種方法好?圖中的情景說明了什么問題?(教師通過所設(shè)計(jì)的情景,將學(xué)生引入怎樣比較做功快慢,讓學(xué)生發(fā)表自己的看法,初步知道物體做功是有快慢之分的。)(三)、進(jìn)行新課1、比較做功快慢的方法播放多媒體素材并提出問題:怎樣比較兩個(gè)人誰做功快誰做功慢?教師啟發(fā):以前學(xué)習(xí)過要比較兩物體運(yùn)動(dòng)的快慢,可以先確定路程再比較時(shí)間,也可以先確定時(shí)間再比較路程。在路程和時(shí)間都不同時(shí),通過計(jì)算速度比較兩物體運(yùn)動(dòng)的快慢。同理,要比較物體做功的快慢可采用什么方法?