The topic of this part is “Discover the reasons for festivals and celebrations.The Listening & Speaking & Talking part aims at talking about the experiences and feelings or emotions about the festivals and celebrations. This section aims at detecting the reason why the people celebrate the festivals, the time, the places, the types and the way of celebrations. It also explains why some traditions in the old celebrations are disappearing, like the firecrackers in the big cities and some new things are appearing like the prosperity of business or commerce. 1. Students can talk about what festivals they know and the reasons and the way of celebrating them.2. Students should learn the reading skills such as the headline and get the topic sentences, the structures of articles.3. Students can understand the past, the present situation of some festival around the world and why there are some changes about them. 4. Students can have the international awareness about the festivals.1. Students should learn the reading skills such as the headline and get the topic sentences, the structures of articles.2. Students can understand the past, the present situation of some festival around the world and why there are some changes about them.Step 1 Lead in---Small talkWhat festival do you like best ? Why ?I like the Spring Festivals because I can set off the fireworks, receive the lucky money and enjoy the Gala with my families.Step 2 Before reading---Pair workWhy do people celebrate different festivals ?The Spring Festivals is to celebrate the end of winter and the coming of spring and new life.The Mid-autumn Day is to celebrate the harvest and admire the moon.
The theme of this section is “Talk about festival activities and festival experiences”.Festival and holiday is a relaxing and interesting topic for students. This part talks about the topic from the daily life of students’. In the part A ---Listening and Speaking, there are three conversations among different speakers from three countries(Japan, Rio and China), where the speakers are participating in or going to participate in the festivals and celebrations. So listening for the relationship among them is a fundamental task. Actually, with the globalization and more international communication, it is normal for Chinese or foreigners to witness different festivals and celebrations in or out of China. In the Conversation 1, a foreign reporter is interviewing a Japanese young girl who just had participated in the ceremony of the Coming-of-Age Day on the street and asking her feeling about the ceremony and the afterwards activities. Conversation 2, Chinese girl Li Mei is witnessing the Rio Carnival for the first time, and her friend Carla gives her some advice on the costumes which enables her to match with the carnival to have a good time. Conversation 3, a Chinese guide is showing a group of foreign visitors around the Lantern Festival and introducing the customs of the festival to them. The three conversations have a strong vitality and insert the festival and cultural elements from different countries. So perceiving the festivals and cultures from different countries is the second task. At the same time, the scripts also insert the targeted grammar --- v-ing as attributive and predicative, which students can perceive and experience in a real context and make a road for the further study. That is the third task. In the Part B--- Listening and Talking, the theme is “Talk about festival experience”, which is the common topic in our daily conversations. During the conversation, Song Lin, a Chinese student, asked Canadian friend Max about how to spend Christmas. In the conversation, Song Lin talked about experience and the feelings during the Chinese Spring Festival, during which there are not only some enjoyable things but some unpleasant things. After the listening, perhaps students find there are some similarities between Christmas and the Chinese Spring Festival as there are some differences in the origins and celebrations. For example, people always visit friends and relatives, decorate their houses, have a big dinner together, chat and give presents to each other.
Step 3 Analyzing article structureActivity 31. Teachers raise questions to guide students to analyze the chapter structure of this diary and think about how to describe the festival experience. (1)What should be included in the opening/body/closing paragraph(s)?(2)How did the writer arrange his/her ideas?(3)What kind of interesting details did the writer describe?(4)How did the writer describe his/her feelings/emotions during the event?2. Students read and compare the three sentence patterns in activity 2. Try to rewrite the first paragraph of the diary with these three sentence patterns. After that, students exchange corrections with their partners. Such as:●This was my first time spending three days experiencing the Naadam Festival in China’s Inner Mongolia Autonomous Region and it was an enjoyable and exciting experience. ●I'll never forget my experience at the Naadam Festival because it was my first time to watch the exciting Mongolian games of horse racing, wrestling, and archery so closely. ●I'll always remember my first experience at the Naadam Festival in China’s Inner Mongolia Autonomous Region because it was so amazing to spend three days witnessing a grand Mongolian ceremony. Step 4 Accumulation of statementsActivity 41. Ask the students to read the diary again. Look for sentences that express feelings and emotions, especially those with the -ing form and the past participle. Such as:● …h(huán)orse racing, wrestling, and archery, which are all so exciting to watch. ● some amazing performances● I was surprised to see…● I was a little worried about. . . ● feeling really tiredOther emotional statements:●I absolutely enjoyed the archery, too, but the horse races were my favourite part. ●I'm finally back home now, feeling really tired, but celebrating Naadam with my friend was totally worth it. ●He invited me back for the winter to stay in a traditional Mongolian tent and cat hot pot. I can’t wait!2. In addition to the use of the -ing form and the past participle, the teacher should guide the students in the appreciation of these statements, ask them to memorize them, and encourage them to use them reasonably in writing practice.
The topic of this part is “Write about your festival experience”.During the Listening and Speaking and Talking, students are just asked to say out their festival experiences such as the Spring Festival, Mid-autumn Day, but this part students will be asked to write down their own festival experiences. During the reading part, it introduces the Naadam Festival in Inner Mongolia Autonomous Region, which can give students a good example to imitate. Students not only learn the festival, but touch and feel the Inner Mongolian’s character, the spirit and cultural atmosphere, which can help students form the cultural awareness and learn to enjoy and value the diversity of Chinese culture.Concretely, the dairy tells the experience that the author spent the Naadam Festival in Inner Mongolia Autonomous Region with his/her friend. The structure is clear. In the opening paragraph, it introduces the topic of the Naadam Festival and the whole feeling. Then it introduces the items of the festival like the ceremony, wrestling and horse racing. Finally, it summarizes this experience. Because this part is a travel journal, we must guide students pay more attention to these details: 1. use the first person. 2. use the past tense to tell the past thing and use the present or future tense to describe the scenery. 3. use the timeline to tell the development. 4. be careful for the author’s psychology, emotion and feeling, etc.1. Read quickly to get main idea; read carefully to get the detailed information about Naadam Festival.2. Learn the structure of the reading article and language.3. Write an article about a festival experience4. Learn to use the psychology, emotions and feeling in the writing.1. Write an article about a festival experience.2. Use the structure of the reading article and language.
四.設(shè)計(jì)反思我在設(shè)計(jì)本課時(shí),希望通過情境的創(chuàng)設(shè)充分再現(xiàn)歷史,并利用多媒體輔助教學(xué),破重點(diǎn)、化難點(diǎn),讓學(xué)生主動(dòng)參與到學(xué)習(xí)過程中,從而突破狹小的教室空間,讓學(xué)生真正做到感知?dú)v史,立足現(xiàn)實(shí),展望未來。自主,交流、合作、探究是課程改革中著力倡導(dǎo)的新型學(xué)習(xí)方式。課堂教學(xué)中如何開展小組合作的探究學(xué)習(xí)存在著很多困難,首先是課堂教學(xué)時(shí)間有限,如何體現(xiàn)面向全體,給每個(gè)學(xué)生以機(jī)會(huì)?再次,歷史問題的討論只能依托于史料才能使討論不淪為空談,課堂上通過網(wǎng)絡(luò)提供大量的史料(文字、圖片或其他),勢(shì)必不能有充分時(shí)間讓學(xué)生閱讀分析。如何解決這些問題呢?措施一:要形成較固定的歷史學(xué)習(xí)合作小組。選定一位同學(xué)擔(dān)任組長(zhǎng),負(fù)責(zé)協(xié)調(diào)措施二:要設(shè)置有利于學(xué)生探究的問題情境措施三:要把課堂教學(xué)與課外學(xué)習(xí)結(jié)合起來。在課前就印發(fā)相關(guān)的材料,或引導(dǎo)學(xué)生去查閱相關(guān)的資料,讓學(xué)生有個(gè)充分的閱讀、思考、交流的時(shí)間,是保證課堂上小組交流能成功實(shí)現(xiàn)的一個(gè)前提
2、教學(xué)目標(biāo)根據(jù)我對(duì)教材的理解、結(jié)合學(xué)生的實(shí)際情況、滲透新課程的教學(xué)理念,為提高全體學(xué)生的科學(xué)素養(yǎng),按課程標(biāo)準(zhǔn),以促進(jìn)全體學(xué)生發(fā)展為目的。從知識(shí)與技能、過程與方法,情感態(tài)度與價(jià)值觀三個(gè)方向培養(yǎng)學(xué)生,擬定三個(gè)教學(xué)目標(biāo):知識(shí)與技能:(1)知道什么是動(dòng)能。(2)正確理解和運(yùn)用動(dòng)能公式分析、解答有關(guān)問題。(3)掌握外力對(duì)物體所做的總功的計(jì)算,理解“代數(shù)和”的含義。(4)理解和運(yùn)用動(dòng)能定理。過程與方法:通過演繹推理過程,培養(yǎng)科學(xué)研究興趣,領(lǐng)略物理學(xué)中所蘊(yùn)含的嚴(yán)謹(jǐn)?shù)倪壿嬯P(guān)系。情感、態(tài)度、價(jià)值觀:通過運(yùn)用動(dòng)能定理分析解決問題,感受成功的喜悅,培養(yǎng)學(xué)生對(duì)科學(xué)研究的興趣。3、教學(xué)的重點(diǎn)和難點(diǎn)重點(diǎn):理解動(dòng)能定理、應(yīng)用動(dòng)能定理解決力學(xué)問題。難點(diǎn):應(yīng)用動(dòng)能定理解決多個(gè)過程的力學(xué)問題,以及變力做功或曲線運(yùn)動(dòng)中的動(dòng)能定理運(yùn)用。
當(dāng)代社會(huì)生活的變化比以往任何時(shí)代都要快。語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。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,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,也有一些流行語又逐漸受到冷遇,甚至退隱。為了更好的對(duì)新詞新語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。
1)他們?cè)诔踔械纳飳W(xué)學(xué)習(xí)中已具備了一定的關(guān)于光合作用的基礎(chǔ)知識(shí),也做過“綠葉在光下制造淀粉”這個(gè)實(shí)驗(yàn)。2)他們具備物質(zhì)轉(zhuǎn)變和能量變化等相關(guān)的化學(xué)知識(shí)。3)在前面的《降低化學(xué)反應(yīng)活化能的酶》一節(jié)的學(xué)習(xí)中已經(jīng)學(xué)習(xí)過簡(jiǎn)單的對(duì)照實(shí)驗(yàn)和相關(guān)的實(shí)驗(yàn)設(shè)計(jì)原則,使本節(jié)課最后的實(shí)驗(yàn)設(shè)計(jì)得以順利進(jìn)行。4)他們具有一定的 分析問題的能力,實(shí)施問題探究教學(xué)是可行的。三、教法和學(xué)法根據(jù)上述對(duì)教材和學(xué)生的分析,本節(jié)采用以下教法和學(xué)法:1)實(shí)驗(yàn)法:以實(shí)驗(yàn)說明結(jié)論。生物學(xué)的教學(xué)就是實(shí)驗(yàn)的教學(xué)過程,實(shí)驗(yàn)的展示形式有學(xué)生分組實(shí)驗(yàn)、老師示范實(shí)驗(yàn)、動(dòng)畫和圖片演示實(shí)驗(yàn)等,讓實(shí)驗(yàn)現(xiàn)象說明問題,而不是直接讓學(xué)生記住結(jié)論。2)問題探究教學(xué)發(fā):以問題引發(fā)興趣。整個(gè)教學(xué)過程要設(shè)置好問題,層層展開,層層遞進(jìn),讓新知識(shí)與舊知識(shí)融為一個(gè)整體,讓學(xué)生在步步上升中攀登到知識(shí)的頂峰。3)比較學(xué)習(xí)法,同時(shí)采用多媒體輔助教學(xué),解決光合作用抽象的過程。
今天我說課的內(nèi)容是人教版高中物理必修1第四章第四節(jié)《力學(xué)單位制》,我的說課內(nèi)容將按下列程序展開。首先是本節(jié)教材的分析。一、說教材1、本節(jié)課在教材中的地位單位是學(xué)生在高考中最容易犯錯(cuò)的地方之一,本節(jié)課內(nèi)容貫穿整個(gè)物理學(xué)科的每部分。學(xué)好這部分內(nèi)容對(duì)所有的自然學(xué)科都有幫助。2、教材簡(jiǎn)析教材可分為:?jiǎn)挝恢频雀拍畹膩碓春蛦挝恢频耐茝V。二、說教學(xué)目標(biāo):教學(xué)目標(biāo)的設(shè)定是教師進(jìn)行課堂授課的一個(gè)重要依據(jù),是教師完成教學(xué)任務(wù)的鑒定標(biāo)準(zhǔn)。根據(jù)新課標(biāo)要求和學(xué)生特點(diǎn)我對(duì)本節(jié)制定以下教學(xué)目標(biāo)(1)了解什么是單位制,知道國際單位制中力學(xué)的三個(gè)基本單位。(2)認(rèn)識(shí)單位制在物理學(xué)中和國際交往中的重要作用。(3)學(xué)會(huì)用單位運(yùn)算來檢查物理公式推導(dǎo)的正確性,從而培養(yǎng)學(xué)生解決實(shí)際問題的能力。
研究一種物理現(xiàn)象,總是要先從現(xiàn)象的描述入手。機(jī)械運(yùn)動(dòng)作為自然界最簡(jiǎn)單和最基本的運(yùn)動(dòng)形態(tài),它所描述的是物體空間位置隨時(shí)間變化的情況。因此,本節(jié)學(xué)習(xí)描述質(zhì)點(diǎn)做機(jī)械運(yùn)動(dòng)需要時(shí)刻、時(shí)間間隔和位移等概念。相當(dāng)一部分高一學(xué)生在具體過程中難以區(qū)別時(shí)刻和時(shí)間間隔。另外,由于思維的定式,在第一次接觸既要考慮大小又要考慮方向的問題時(shí),會(huì)因不適應(yīng)造成學(xué)習(xí)困難。所以,區(qū)別“路程與位移”“時(shí)刻和時(shí)間間隔”是教學(xué)的重難點(diǎn)所在。學(xué)習(xí)這些內(nèi)容的過程與方法對(duì)學(xué)習(xí)速度和加速度可以起到奠定基礎(chǔ)的作用。教學(xué)的對(duì)象是高一的學(xué)生,這一時(shí)期的學(xué)生處在好奇善問、創(chuàng)新意識(shí)強(qiáng)烈的青少年期。對(duì)于生活中出現(xiàn)的各種現(xiàn)象具有濃厚的興趣。但他們的思維還停留在簡(jiǎn)單的代數(shù)運(yùn)算階段,對(duì)于矢量和矢量運(yùn)算的理性認(rèn)識(shí)幾乎沒有。且對(duì)生活中出現(xiàn)的時(shí)間、時(shí)刻、時(shí)間間隔等不能做出很好的區(qū)分,對(duì)時(shí)常提及的路程、距離等形成了模糊的前概念。
一、說教材《質(zhì)點(diǎn) 參考系和坐標(biāo)系》是人教版普通高中物理必修一第一章第一課的內(nèi)容。本節(jié)課主要介紹了質(zhì)點(diǎn)、參考系、坐標(biāo)系的基本概念。通過本節(jié)課的學(xué)習(xí)為進(jìn)一步學(xué)習(xí)后續(xù)課程起到了鋪墊的作用。根據(jù)上述教材的結(jié)構(gòu)和內(nèi)容分析,又考慮到高一年級(jí)學(xué)生的認(rèn)知結(jié)構(gòu)及其心理特征,我制定了以下三維教學(xué)目標(biāo):1、知識(shí)與技能:知道質(zhì)點(diǎn)的概念及條件;知道參考系的概念及作用;掌握坐標(biāo)系的簡(jiǎn)單應(yīng)用。2、過程與方法:促進(jìn)學(xué)生自主學(xué)習(xí),讓學(xué)生積極參與、樂于探究、勇于實(shí)驗(yàn)、勤于思考,培養(yǎng)學(xué)生的科學(xué)探究能力。3、情感態(tài)度與價(jià)值觀:通過質(zhì)點(diǎn) 參考系和坐標(biāo)系的學(xué)習(xí),使學(xué)生了解生活與物理的關(guān)系,讓學(xué)生學(xué)會(huì)用科學(xué)的思維去看待事物。根據(jù)普通高中物理課程標(biāo)準(zhǔn),并在吃透教材的基礎(chǔ)上,我確定了以下教學(xué)重點(diǎn)和難點(diǎn):教學(xué)重點(diǎn):質(zhì)點(diǎn)概念的建立。只有掌握了這一點(diǎn)才能更加準(zhǔn)確的理解和掌握后續(xù)教材的相關(guān)內(nèi)容。
第11段很短,只點(diǎn)出了這是“在婦女身上搞不育試驗(yàn)的地方”,但在最末又加了一句“否則他會(huì)羞紅了臉的”,這是為什么?那肯定是一個(gè)極為骯臟,極為殘酷的地方。據(jù)資料記載:當(dāng)時(shí)的希特勒制定一項(xiàng)令所有被征服或占領(lǐng)國家的民族充當(dāng)奴隸并且逐漸消亡的隱密性種族滅絕計(jì)劃——高效率、大規(guī)模的強(qiáng)制絕育。為此,數(shù)以百計(jì)的納粹醫(yī)生、教授、專家甚至護(hù)士,在行政管理專家的通力合作下,相繼提出了幾十種絕育方法,十余種實(shí)施方案,并且在奧斯維辛、拉芬斯布呂克、布亨瓦爾特、達(dá)豪等十多個(gè)大型集中營(yíng)內(nèi)對(duì)數(shù)以萬計(jì)的猶太、吉普賽囚犯、因從事抵抗運(yùn)動(dòng)而被捕的政治犯和男女戰(zhàn)俘進(jìn)行了殘酷的手術(shù)試驗(yàn),造成他們大量死亡或者終身殘疾、終身不育。這樣殘酷的毫無人性的手段,任誰也不愿看到。
一、說教材《別了,不列顛尼亞》是編排在人教版《普通高中課程標(biāo)準(zhǔn)實(shí)驗(yàn)教科書語文1(必修)》第四單元的課文,是精讀課文《短新聞兩篇》中的一篇,另一篇是《奧斯維辛沒有什么新聞》。這一單元的學(xué)習(xí)內(nèi)容是新聞和報(bào)告文學(xué),還有兩篇作品分別是中國報(bào)告文學(xué)三大里程碑之一的《包身工》和記錄中國航天事業(yè)輝煌發(fā)展的《飛向太空的航程》。在當(dāng)今信息大爆炸的時(shí)代,如何快速獲得信息,如何在新聞中解讀事件的真相,感悟生活的內(nèi)涵成為語文教學(xué)的又一重大任務(wù)。因此這一單元的編入便更多地具有了時(shí)代意義,體現(xiàn)了語文學(xué)科與日常生活的密切關(guān)系。不僅如此,新聞特寫和報(bào)告文學(xué)的選入,拓寬了學(xué)生對(duì)新聞?lì)愇恼碌牧私?,體現(xiàn)語文學(xué)科的工具性作用。在選文的過程中,新教材同時(shí)注重語文學(xué)科的人文性,四篇作品不僅傳遞著新鮮、真實(shí)的信息,同時(shí)更張顯人文性的厚度,他們以飽滿的情感,縱橫的歷史經(jīng)驗(yàn)。
二、說學(xué)生本屆高一學(xué)生經(jīng)過了三年初中課改,在心理上,他們渴望表現(xiàn)的欲望和自主探究的欲望比較強(qiáng)烈,對(duì)有興趣的知識(shí)表現(xiàn)出高度地?zé)崆?,并具有一定的團(tuán)結(jié)協(xié)作能力,但還是應(yīng)該正視一個(gè)并不樂觀的現(xiàn)實(shí)——在寫作方面,學(xué)生知識(shí)還停留在簡(jiǎn)單的記敘及表達(dá)方式綜合運(yùn)用上,至于巧妙構(gòu)思、謀篇布局很是空白。即便已經(jīng)經(jīng)過高中一個(gè)學(xué)期的學(xué)習(xí),但還是有大部分學(xué)生依然基礎(chǔ)較為薄弱,甚至出現(xiàn)不知從何下筆的現(xiàn)象。三、說教法與學(xué)法“老師搭臺(tái),學(xué)生唱戲”1、教法:本課將安排兩課時(shí)(一課時(shí)學(xué)習(xí)一課時(shí)練筆),采用 PPT 多媒體課件教學(xué),嘗試用角色扮演法、圖片展示法和多媒體教學(xué)等方法,教學(xué)中應(yīng)該重視學(xué)生的參與性和探究性。2、學(xué)法:學(xué)生應(yīng)該充分利用多角度創(chuàng)設(shè)的學(xué)習(xí)情境來激發(fā)自身學(xué)習(xí)的興趣和熱情,分組討論,小組互助等形式讓學(xué)生積極自主參與、進(jìn)行問題探究學(xué)習(xí)。理論依據(jù):建構(gòu)主義理論“學(xué)生是學(xué)習(xí)的中心”的闡釋,教師應(yīng)該做學(xué)生主動(dòng)建構(gòu)意義的幫助者、促進(jìn)者。
在學(xué)習(xí)語文經(jīng)驗(yàn)交流會(huì)上,季老師舉著我的《采花釀蜜集》,對(duì)大家說:“人日積月累辛勤采擷,終于釀出了知識(shí)的瓊漿。大家都應(yīng)這樣,爭(zhēng)做知識(shí)的富戶??!”老師有點(diǎn)激動(dòng),低低地爬在鼻梁上的眼鏡突然滑了下來,正好落在那集子上。大家笑了,季老師也笑了。就這樣,我的寫作有了進(jìn)步,好幾篇作文登上了班級(jí)《學(xué)作園地》。從此,我愛上了語文,更深深地愛上了季老師。高中升學(xué)考前那個(gè)星期天的夜晚,季老師舊病復(fù)發(fā),累倒了。半夜,老師們把他送進(jìn)了公社衛(wèi)生院。第二天,同學(xué)們都悄悄去衛(wèi)生院看望。我去的時(shí)候,季老師正在掛滴流??墒?,下午季老師又出現(xiàn)在講臺(tái)上,他臉色憔悴,聲音沙啞……我手捧《采花釀蜜集》走近季老師,思緒的溪水從遠(yuǎn)方流了回來。“季老師”,我把本子捧給老師,深情地叫了聲。季老師接過本子,仔細(xì)翻閱著,臉上露出了笑容,像是聞到了郁郁芳香的蜜汁似的?!斑M(jìn)步不小呀!”季老師說著,又在本子扉頁上題了
問:為什么會(huì)出現(xiàn)這樣的情況,男女生之間的拉力存在著怎樣的大小關(guān)系?進(jìn)一步求證這兩個(gè)力的大小關(guān)系經(jīng)過共同討論,得方案:把兩個(gè)彈簧秤勾在一起,重現(xiàn)拔河比賽,分三種情況進(jìn)行。(通過攝像頭把彈簧秤的讀數(shù)放大)兩彈簧稱勾在一起拉,處于靜止不動(dòng)時(shí)(即拔河比賽,雙方處于僵持狀態(tài))兩彈簧稱勾在一起拉,并向一方運(yùn)動(dòng)(即比賽繩子被拉向一方時(shí)的狀態(tài))3、兩彈簧稱勾在一起拉,一方方向慢慢改變(兩力方向始終在一條直線上)實(shí)驗(yàn)結(jié)論:兩彈簧稱的讀數(shù)的變化總是相同的,大小相等,方向相反。得到牛頓第三定律:追問:既然兩個(gè)力大小相等,那么拔河比賽為什么還存在勝負(fù)之分?講清作用力與反作用力作用的受力物體不同,并和學(xué)生討論如何做才會(huì)獲勝。回應(yīng)課前問題:“以卵擊石”為什么雞蛋碎?
進(jìn)一步引導(dǎo)學(xué)生思考利用數(shù)學(xué)知識(shí)可寫成等式F=kma學(xué)生很自然就會(huì)思考比列系數(shù)K應(yīng)該是多少?通過教師引導(dǎo)學(xué)生舉例各國長(zhǎng)度單位不同(如英國:英里、碼、英尺、英寸;中國:市里、市丈、市尺、市寸、市分 )導(dǎo)致交流不便。為了適應(yīng)各國交流需要國際計(jì)量局規(guī)定了一套統(tǒng)一的單位,稱為國際單位制 。取不同的單位制K是不同的,為了簡(jiǎn)潔方便,在選取了質(zhì)量和加速度的國際單位(Kg, m/s2)時(shí)規(guī)定K=1。那么就有;F=ma為了紀(jì)念牛頓,就把能使1kg物體獲得1m/s2加速度的力稱做一牛頓,用符號(hào)N表示問題:實(shí)際物體受力往往不止一個(gè),多個(gè)力情況應(yīng)該怎么辦呢?平行四邊形法則進(jìn)一步引導(dǎo)學(xué)生得出牛頓第二定律更一般的表達(dá)式: F合=ma思考.討論我們用力提一個(gè)很重的箱子,卻提不動(dòng)它。這個(gè)力產(chǎn)生了加速度嗎?要是產(chǎn)生了,箱子的運(yùn)動(dòng)狀態(tài)卻并沒有改變。為什么?
(5)高度不同,對(duì)平拋運(yùn)動(dòng)距離有何影響,是否因?yàn)楦叨葴p小后下落時(shí)間減小,所以要增大速度才能達(dá)到相同的距離?(教學(xué)實(shí)踐證明,這種想法在學(xué)生比較多見。已經(jīng)不自覺的沿用了自由落體運(yùn)動(dòng)的規(guī)律,又隱隱有運(yùn)動(dòng)等時(shí)性的痕跡。應(yīng)引導(dǎo)學(xué)生這一結(jié)果還需實(shí)驗(yàn)驗(yàn)證。)教師的引導(dǎo):其實(shí),我們所提出的看法都跟平拋運(yùn)動(dòng)的規(guī)律有關(guān)系。那么平拋運(yùn)動(dòng)究竟有怎樣的規(guī)律呢?以前學(xué)過的直線運(yùn)動(dòng)知識(shí)還能用于今天的內(nèi)容嗎?由此逐步使學(xué)生意識(shí)到分析平拋運(yùn)動(dòng)須采用運(yùn)動(dòng)合成與分解這一方法。三、實(shí)驗(yàn)驗(yàn)證自主探究(15分鐘) 物理是實(shí)驗(yàn)科學(xué),多媒體教學(xué)不能代替實(shí)驗(yàn)。本教學(xué)設(shè)計(jì)的第三個(gè)環(huán)節(jié)是實(shí)驗(yàn)驗(yàn)證,鼓勵(lì)學(xué)生自主探究。引導(dǎo)學(xué)生根據(jù)自己的猜想(實(shí)驗(yàn)?zāi)康模┰O(shè)計(jì)實(shí)驗(yàn)進(jìn)行驗(yàn)證。(1)介紹手持式平拋豎落儀,引導(dǎo)并小結(jié)實(shí)驗(yàn)要領(lǐng):聽兩小球下落聲音判斷其下落時(shí)間。體會(huì)合運(yùn)動(dòng)和分運(yùn)動(dòng)是等時(shí)的。
1、舉例:2、結(jié)論:(1)物體的運(yùn)動(dòng)軌跡是曲線的運(yùn)動(dòng)叫曲線運(yùn)動(dòng)。(2)曲線運(yùn)動(dòng)中速度方向是時(shí)刻改變的。(二)、曲線運(yùn)動(dòng)方向:1、質(zhì)點(diǎn)在某一點(diǎn)(或某一時(shí)刻)的速度的方向是在曲線的這一點(diǎn)的切線方向。2、曲線運(yùn)動(dòng)中速度方向是時(shí)刻改變的,因此曲線運(yùn)動(dòng)是變速運(yùn)動(dòng)。(三)、曲線運(yùn)動(dòng)條件:1、演示實(shí)驗(yàn):2、結(jié)論:當(dāng)物體所受的合力的方向跟它的速度方向不在同一直線時(shí),物體就做曲線運(yùn)動(dòng)。七、課堂小結(jié):1、運(yùn)動(dòng)軌跡是曲線的運(yùn)動(dòng)叫曲線運(yùn)動(dòng)。2、曲線運(yùn)動(dòng)中速度的方向是時(shí)刻改變的,質(zhì)點(diǎn)在某一點(diǎn)的瞬時(shí)速度的方向在曲線的這一點(diǎn)的切線上。3、當(dāng)合外力F的方向與它的速度方向有一夾角a時(shí),物體做曲線運(yùn)動(dòng)。八、鞏固訓(xùn)練:1、關(guān)于曲線運(yùn)動(dòng),下列說法正確的是()。A:曲線運(yùn)動(dòng)一定是變速運(yùn)動(dòng);B:曲線運(yùn)動(dòng)速度的方向不斷的變化,但速度的大小可以不變;
設(shè)計(jì)意圖:通過設(shè)疑、討論及學(xué)生的親身體驗(yàn)與教師的引導(dǎo),得到描述圓周運(yùn)動(dòng)快慢的兩個(gè)物理量,也就成功的打破了學(xué)生在認(rèn)識(shí)上的思維障礙,突破了物理概念教學(xué)的難點(diǎn)。在解決線速度和角速度的問題之后,我將引領(lǐng)學(xué)生學(xué)習(xí)勻速圓周運(yùn)動(dòng)的概念以及勻速圓周運(yùn)動(dòng)中線速度、角速度的特點(diǎn)。并引出勻速圓周運(yùn)動(dòng)中周期、轉(zhuǎn)速的知識(shí)。為了加深學(xué)生對(duì)線速度、角速度與半徑關(guān)系的認(rèn)識(shí),我設(shè)計(jì)了第三個(gè)學(xué)生體驗(yàn)活動(dòng):四名學(xué)生以我為圓心做圓周運(yùn)動(dòng),四名學(xué)生始終并列,這時(shí)里圈同學(xué)走動(dòng)不急不慢,而外圈同學(xué)則要小跑。通過學(xué)生的活動(dòng),不難發(fā)現(xiàn)在角速度相同的情況下,半徑越大的線速度也越大。定性的得到了線速度、角速度與半徑的關(guān)系。接下來讓學(xué)生利用所學(xué)知識(shí)推導(dǎo)線速度、角速度與半徑的關(guān)系。設(shè)計(jì)意圖:這樣就通過設(shè)疑、學(xué)生猜想、體驗(yàn)、推導(dǎo)的方式得到了結(jié)論,突破了本節(jié)課的難點(diǎn)即線速度、角速度與半徑的關(guān)系。