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新人教版高中英語必修2Unit 5 Music-Listening＆Speaking＆Talking教案
choir memberspeople to run food stands people to sell festival ticketspeople to sell music CDspeople to set up equipmentmusical performersStep 2: Listen to the announcement again and answer the questions. ? 1. What kind of songs will Grace Davis sing at the festival?? 2. Who can try out as a performer?? 3. What can those who think they do not have musical talent do?? 4. How can students volunteer to take part?? Talking about preferences:? Would you prefer doing ..?? What would you prefer to do?? Would you rather do .... or ….?? What would you rather do?? I'd prefer .... to ..? I'd rather have ... than .. Step 3: Speaking ProjectWork in groups. Role-play the conversation or make a new one.? Debbie: Where have you been? You missed the announcement about the music festival.? John: I was at the doctor's office. Music festival?? Frank: Yes, it's going to be next month on the school sports field. John, you can play the piano. How about playing it at the festival?? John: Well, I'd rather play the violin. I can play Liang Zhu.? Frank: Wow! Sounds good. What about you, Debbie? ? Debbie: Actually, I don't have much musical ability. I'd prefer just to help out with the crowds.? Frank: You can sell tickets or work at a food stand.? John: So can I assume that the aim of the festival is to raise money?? Debbie: Yes. All of the money will go to charity.
新人教版高中英語必修2Unit 5 Music-Reading and Thinking教案二
1. Get basic information about Eric; read deeply to understand the history and development of the virtual choir.2. Understand what the function of the virtual choir is and how to make a virtual choir.3. Understand the meaning of some languages in the context of the text through question guidance, such as “Many people do not have close friends or contacts who have the same interest in music.” and so on.Step 1 Leading-in1. Answer the following questions.Q1：Do you know the Apps like Tik Tok and Quick Hand?Q2: Do you want to make a Tik Tok video or a Quick Hand video?2. Play a Tik Tok video Step 2: Understanding the title Q1：What does the title mean ?Q2: Is the article a narration or exposition? Why? Q3: Can you change the title ? If you can, what is the title?Step 3: Scanning the whole text and getting the basic information1. Answer the following questions.Q1：Who came up with the idea for a virtual choir?Q2: Where did Eric studied the musical composition?Q3: What is his song?2. Find the main idea of each paragraph3. Deal with some new words.Step 4: Reading carefully to get detailed informationPara 1 How to make a virtual choir1. PreparationA. tools: a virtual camera; an Internet connectionB. hero/heroin: friends or some individuals who have the same interests2. Process
新人教版高中英語必修2Unit 5 Music-Reading for Writing教案二
The Internet celebrity Gao Yifeng. Years ago, he owned 5 companies and the staffs over 1,000, but during the economy crisis, he became nothing but debt. He was so worried that his hair became white overnight. There was a time when he wanted to killed himself. But after listening to the song Start Over by Liu Huan, he decided to cheer himself up. He started a steamed bun shop and gradually became a national chain shops. Now he became successful again.Walter Haddon said, “Music is the medicine of a troubled mind.” Music contains such a pleasant and inspiring force. Music gave him courage and bravery. When he listened to the song, it made his spirit fly like a kite in the wind. Music gave him strength and brought him relief. It was the rock I leant on to become strong and to get through those hard times. I hope none of us have to go through the same kind of suffering that he did. At the same time, we all go through various periods when we feel sad or alone. During those times, music can help us in the same way that it helped him. I hope we all will somehow begin to treasure music and make it a part of our life. Thank you for your listening !5.Revise your writing each other.Does he/she explain how music has changed his/her/someone else’s life?Are some of the rhetorical devices included and used properly ?Does he/she talk about how music makes him/her/someone feel?Is the first word in each sentences capitalised?Does he/she use correct punctuation ?
新人教版高中英語選修1Unit 5 Working the Land教案
1. 完成文本主要信息填空（斜體字部分設(shè)空）：As a witness to farmers’ poor harvests and even a severe shortage of food, Yuan Longping was determined to devote his life to tackling this crisis. After graduation, he realized that what farmers needed most was to boost yields in the fields. Yuan was convinced that the answer lay in the creation of hybrid rice, one characteristic of which is that it usually achieve higher output than conventional crops. However, it was no easy job. The first difficulty he needed to overcome was scientists’ general assumption that this could not be done. Through trial and error, Yuan managed to generate this incredible crop. It is estimated that about 60 percent of domestic rice consumption in China was comprised of crops generated from Yuan’s hybrid strains. His innovation has enabled Chinese farmers to considerably expand their output and helped feed the world. Unwilling to retire early to a life of leisure and unconcerned about celebrity or fortune, Yuan continues to turn one vision after another into realities.2. 模仿寫作：Do some research via the Internet and introduce another agricultural scientist, Chen Risheng（陳日勝）, using the structure, expressions and writing techniques you have learnt from the text “A Pioneer for All People”.【設(shè)計(jì)意圖】任務(wù)1是對(duì)文本內(nèi)容和詞匯學(xué)習(xí)成效的檢測(cè)。任務(wù)2借助文本中學(xué)到的詞匯和寫作手法仿寫另一位科學(xué)家，提升學(xué)生遷移運(yùn)用詞匯、文體結(jié)構(gòu)和寫作方法的能力。
新人教版高中英語選修3Unit 2 Healthy Lifestyle教案
Activity 4: Figuring out the structure and the writing purpose 本活動(dòng)為實(shí)現(xiàn)課時(shí)目標(biāo)2。 1.Read Paragraph 6 and think about its main idea and the writer’s writing purpose. Q1: If you were the author, how would you end your article? “For young people, there is plenty of time to change bad habits. However, there is no “magic pill” or delete button that will help you; you have to think about your bad habits and decide on some changes. You have the power to build a happy and healthy life full of good habits!” Q2: What is Paragraph 6 mainly about? (Possible answer: to appeal to young people including teenagers to change bad habits and live a happy and healthy life.) 2.Think about the writer’s writing purpose and share opinions. Q1: What is the writing purpose? Work in pairs and figure it out. (Possible answer: On the one hand, the passage is written to help teenagers change their bad habits and live a healthy lifestyle. On the other hand, it provides us with a scientific way to identify and analyse our problems objectively, thus strengthening our resolve to tackle the seemingly common yet tough problems in our lives.) 【設(shè)計(jì)意圖】 步驟1旨在預(yù)測(cè)和驗(yàn)證文章最后一段主要內(nèi)容，梳理完整的語篇結(jié)構(gòu)，步驟2旨在思考和討論作者的寫作目的。教師也可根據(jù)學(xué)生課堂反應(yīng)情況融入對(duì)語篇人稱多次轉(zhuǎn)換的思考。
新人教版高中英語選修4Unit 2 Iconic Attractions教案
幫助學(xué)生通過討論與對(duì)主題的提升，反思自己的旅游方式，以便做出更優(yōu)化的安排，在今后的旅程中有更多的收益。 Activity 2: Further discussion of the 6 elements above and supplement of more background knowledge 本活動(dòng)為實(shí)現(xiàn)課時(shí)教學(xué)目標(biāo)2。 1.Target Q: The writer’s clear target of traveling, meeting the people and experiencing the culture, is closely related to his major in social studies. Then what is social studies? Social studies is a part of a school or college curriculum concerned with the study of social relationships and the functioning of society and usually made up of courses in history, government, economics, civics, sociology, geography, and anthropology. （Dictionary by Merriam-Webster） Reflection: When you go out to travel, what targets do you usually have in mind? 2.Research Q: Suppose you are traveling to Hangzhou during the school holidays, how will you do research on the city? (surf the internet, read books or travel brochures, consult friends, ...) What information will you be interested to know? (location, iconic sites, local cuisines, interesting customs, shopping malls ...) 3.Abandonment To make the most of time, we have to learn to abandon so that we can accomplish our plan. What will you be interested in doing if you go to Hangzhou if you have a week’s time? What if you only have 2 days? 4~5. Venturing & Experiencing Q: What did he venture to do during the trip? What new experiences did he have? In Sydney: attend his first open-air barbecue, enjoy many different but yummy meals In Catherine: observe the life and customs of the aborigines appreciate their music & try the musical instruments: the didgeridoo
新人教版高中英語選修4Unit 4 Sharing教案
【核心素養(yǎng)提升點(diǎn)】學(xué)會(huì)將抽象信息進(jìn)行可視化表達(dá)，提高信息處理能力和分析、推理等高階思維品質(zhì)；在跨文化交際中學(xué)會(huì)以國際視野接受和包容不同的文化。 5.Read Paragraph 2, draw a mind map and answer the questions. Q1:What did Jo learn about Tombe’s life? Q2:What kind of life do the natives lead? Read paragraph 2-5 and draw a mind-map. (Focus on accommodation, possession, diet and belief) 【設(shè)計(jì)意圖】引導(dǎo)學(xué)生利用思維導(dǎo)圖和問題鏈等形式來厘清當(dāng)?shù)厝说纳罘绞?，更好地處理和歸納信息 【核心素養(yǎng)提升點(diǎn)】提高信息處理能力、分析和歸納能力，包容異國文化、擴(kuò)展國際視野。 6.Read Paragraph 3 and answer the questions. Q1:What was Jo’s feeling upon arriving her own home? Q2:Why would she feel that way? Q3:Do you think “It was such a privilege to have spent a day with Tombe’s family”? 【設(shè)計(jì)意圖】通過提問，讓學(xué)生理解Jo的苦并快樂的心情，并通過對(duì)“It was such a privilege to have spent a day with Tombe’s family”這句話的理解，體驗(yàn)志愿者生活的偉大。 【核心素養(yǎng)提升點(diǎn)】學(xué)會(huì)對(duì)信息的綜合和歸納，從而理解作者所表達(dá)的觀點(diǎn)。 Activity4: Summarize the change of Jo's feelings
人教部編版七年級(jí)語文上冊(cè)如何突出中心教案
我們一家乘車行駛在黃土高原上，眺望遠(yuǎn)處云朵，盡情享受著清風(fēng)的洗禮……因?yàn)槲覀円乩霞覈D！倘若乖乖地欣賞美景，是坐不住的。雖說有起伏不定的高原，波濤洶涌的黃河，不時(shí)從石縫里“蹦”出來的水絲簾，一望澄澈的藍(lán)天，悠然飄過的白云……可當(dāng)這一切的美景同時(shí)“刷”在你的眼前，且接連不斷地出現(xiàn)時(shí)，還是會(huì)讓你感到幾分乏味。因?yàn)椋@可是八小時(shí)的長途跋涉??！每到這時(shí)候，車?yán)锏娜藗兙童偪窳似饋?。雖說只有區(qū)區(qū)四人，可還是組成了一個(gè)超級(jí)合唱團(tuán)。不信你看爸爸已經(jīng)興奮起來。只見他清清嗓子，扭動(dòng)身子，接著便“肆無忌憚”地高聲唱起來。媽媽則是一副欲唱又止的樣子，最終也只是淡淡地笑了笑。在這一剎那，媽媽神情是最復(fù)雜也是最可愛的。是快樂還是驕傲？是幸福還是羞澀？總之，略有些放不開。后來，她也開始有節(jié)奏地在車門上敲擊，敲出一串美妙又興奮的聲音。好像她所有的快樂都被譜成了一首無拘無束的歌。
人教版高中歷史必修1祖國統(tǒng)一大業(yè)教案2篇
教材分析改革開放后我國的綜合國力不斷增強(qiáng)，人民對(duì)祖國統(tǒng)一的愿望越來越迫切。本節(jié)課以“一國兩制”構(gòu)想的提出，香港、澳門的回歸和海峽兩岸關(guān)系的發(fā)展為中心，說明實(shí)現(xiàn)祖國統(tǒng)一，完成中華民族復(fù)興是歷史發(fā)展的必然。第一目“‘一國兩制’構(gòu)想的提出”主要講述了“一國兩制”的含義及歷史意義。第二目“香港、澳門的回歸”著重講述了香港回歸、澳門回歸的經(jīng)過及歷史意義，這是“一國兩制”成功的實(shí)踐。第三目“海峽兩岸關(guān)系的發(fā)展”講述了大陸注重發(fā)展與臺(tái)灣的關(guān)系，促進(jìn)海峽兩岸的經(jīng)濟(jì)文化交流與合作，打破了幾十年來海峽兩岸的隔絕狀態(tài)，促進(jìn)了祖國統(tǒng)一的進(jìn)程。此外，教材還通過“資料回放”“歷史縱橫”“學(xué)思之窗”等欄目，為學(xué)生學(xué)習(xí)提供了一些詳細(xì)的史料。在教學(xué)中要分析圖表資料，引導(dǎo)學(xué)生理解完成祖國統(tǒng)一大業(yè)，實(shí)現(xiàn)中華民族的復(fù)興，是任何人也阻擋不了的歷史潮流。
人教版高中歷史必修3物理學(xué)的重大進(jìn)展教案
B重點(diǎn)與難點(diǎn)重點(diǎn)：伽利略對(duì)物理學(xué)發(fā)展的重大貢獻(xiàn)；經(jīng)典力學(xué)的建立；相對(duì)論的提出；量子論的誕生。難點(diǎn)：物理學(xué)各階段發(fā)展的原因；對(duì)科學(xué)發(fā)展創(chuàng)新性的理解。D教學(xué)過程【導(dǎo)入新課】1632年，伽利略撰寫的《關(guān)于托勒密和哥白尼兩大世界體系的對(duì)話》科學(xué)巨著出版后，立刻引起教會(huì)的恐慌，把伽利略投入監(jiān)獄。教皇烏爾班八世的御用工具——宗教裁判所在1633年6月21日宣布對(duì)伽利略的判決：“我們判決你在宗教法庭監(jiān)獄內(nèi)服刑，刑期由我們掌握，為了有益于補(bǔ)贖，命令你在今后3年內(nèi)，每周背誦7篇贖罪詩篇……”這一紙胡言，竟使伽利略蒙冤300多年，致死都沒有撤銷判決，甚至死后還被禁止舉行殯禮，不準(zhǔn)葬入圣太克羅斯墓地。那么，是什么原因?qū)е伦诮滩门兴鶎?duì)伽利略作了如此判決？我們應(yīng)如何看待伽利略在科學(xué)領(lǐng)域的貢獻(xiàn)？
人教版高中歷史必修2大眾傳媒的變遷教案
【課后研討】當(dāng)互聯(lián)網(wǎng)正大踏步走進(jìn)人類生活的時(shí)候，人們對(duì)網(wǎng)絡(luò)作用的認(rèn)識(shí)似乎還是模糊不清。一種意見認(rèn)為，作為中學(xué)生，他們上網(wǎng)的機(jī)會(huì)很多,互聯(lián)網(wǎng)向他們展示了各類知識(shí)結(jié)構(gòu),網(wǎng)絡(luò)為他們提供了大量信息，又給他們提供了一個(gè)接觸社會(huì)的個(gè)性化和國際化的空間，給了他們一個(gè)展示自身能力的大舞臺(tái),所以他們對(duì)于知識(shí)選擇的靈活性大大增加，學(xué)習(xí)的主動(dòng)性也大大提高，學(xué)習(xí)的內(nèi)容自然大大超出了狹隘的課本范圍，這對(duì)于學(xué)生能力的提高應(yīng)是大有裨益的。另一種意見認(rèn)為，網(wǎng)絡(luò)的出現(xiàn)無疑為推進(jìn)素質(zhì)教育提供了一塊綠洲.但部分中學(xué)生上網(wǎng)更多的是為了消遣和娛樂，因?yàn)榫W(wǎng)絡(luò)--這個(gè)完全虛擬的世界是他們放松自己的最佳場(chǎng)所。同時(shí)也許正基于這一點(diǎn)，家長和師長才會(huì)對(duì)中學(xué)生上網(wǎng)出現(xiàn)不同程度的抵制，因?yàn)樗麄冋J(rèn)為網(wǎng)上娛樂分散了他們過多的精力，會(huì)對(duì)學(xué)業(yè)造成影響；更為重要的是，他們害怕網(wǎng)絡(luò)上的不良信息對(duì)他們的身心不利。
人教版高中地理必修1大規(guī)模的海水運(yùn)動(dòng)教案
4．海洋污染（1）閱讀書本P64，由學(xué)生歸納：（2）展示圖片資料：“威望號(hào)油輪泄漏事故”【討論】石油污染將對(duì)該海區(qū)的生態(tài)環(huán)境造成怎樣的影響？【小結(jié)】本節(jié)課我們從四個(gè)方面了解了洋流對(duì)地 理環(huán)境和人類活動(dòng)的影響，重點(diǎn)學(xué)習(xí)洋流對(duì)氣候和對(duì)漁場(chǎng)形成的影響。同學(xué)們聽說過“厄爾尼諾”現(xiàn)象嗎？“厄爾尼諾”現(xiàn)象會(huì)影 響秘魯漁場(chǎng)的漁獲量；也會(huì)對(duì)氣候產(chǎn)生影響，導(dǎo)致全球氣候異常?！禾骄俊吧衿娴亩驙柲嶂Z”現(xiàn)象』學(xué)習(xí)小組交流【小結(jié)】“厄爾尼諾”現(xiàn)象還有許多不解之謎，其中之一是形成原因，尚未能解釋清楚。有人認(rèn)為是南半球東南信風(fēng)減弱造成的，也有人認(rèn)為是大氣環(huán)流減弱造成的結(jié)果；且“厄爾 尼諾”現(xiàn)象發(fā)生有沒有自身的規(guī)律？發(fā)生周期長短受什么制約？等等，這些謎團(tuán)等待我們?nèi)ヒ灰唤忾_。
人教版高中地理選修2我國的三大自然區(qū)教案
1、中國三大自然區(qū)的空間位置和基本特征。2、中國自然區(qū)域差異對(duì)人類活動(dòng)的影響。◆重要圖釋圖1.1“三大自然區(qū)圖”三大自然區(qū)的界線（自然地理分界）：西北干旱半干旱區(qū)與東部季風(fēng)區(qū)之間大致以400mm等年降水量線為界，青藏高寒區(qū)與東部季風(fēng)區(qū)約以3000米等高線為界，青藏高寒區(qū)與西北干旱半干旱區(qū)以昆侖山——阿爾金山——祁連山為界。【學(xué)習(xí)策略】1、讀圖分析：通過讀圖、分析、歸納的方法，識(shí)記三大自然區(qū)的空間位置、相互界線，理解各自然地理要素的特征和空間分布規(guī)律。2、綜合訓(xùn)練：運(yùn)用空白地圖，將地理事物落實(shí)在圖上，并進(jìn)行比較分析、歸納整理，理解三大自然區(qū)的區(qū)域差異?！窘虒W(xué)內(nèi)容】一、三大自然區(qū)的劃分1．三大自然區(qū)的劃分依據(jù)（地貌、氣候的地域差異）
小學(xué)美術(shù)人教版一年級(jí)上冊(cè)《第9課我在空中飛》教案
一、組織教學(xué)：檢查學(xué)生用具準(zhǔn)備情況二、講授新課：1、引入階段：引趣，掛出宇宙飛船，宇航員，飛碟等圖案師問：圖上的物體是些什么？是用來干什么的？掛出兩幅完整的太空，科幻作品。介紹簡單的太空知識(shí)和人類深索太空奧秘的活動(dòng)。
部編版語文九年級(jí)上冊(cè)《范進(jìn)中舉》教案
目標(biāo)導(dǎo)學(xué)一：了解作者，了解作品吳敬梓，字敏軒，號(hào)粒民，晚年又號(hào)文木老人，安徽全椒人，清代小說家。吳敬梓出生于一個(gè)科甲鼎盛的縉紳世家，其曾祖父和祖父兩代人中，共出了六名進(jìn)士。受家族的影響，他少時(shí)熱衷科舉，早年入學(xué)為秀才，二十九歲時(shí)參加鄉(xiāng)試，卻因“文章大好人大怪”而遭黜落。不過，讀書生活使他顯露出孤標(biāo)脫俗的叛逆?zhèn)€性。特別是在他的父親去世后，近房中不少人覬覦遺產(chǎn)，使他得以認(rèn)清科甲世家的虛偽和卑劣。吳敬梓性情豁達(dá)，不善治家，不上十年，就將遺產(chǎn)消耗一空。經(jīng)歷了由富到貧之變后，他飽嘗了世態(tài)炎涼，體察到士大夫階層的種種墮落與無恥，看清了清王朝統(tǒng)治下政治的腐敗與社會(huì)的污濁。正因?yàn)槠鋫€(gè)人經(jīng)歷，使他對(duì)當(dāng)時(shí)儒生的生活和精神狀態(tài)之弊病有了深刻的了解，寫下了著名的諷刺小說《儒林外史》。
部編版語文七年級(jí)下冊(cè)《河中石獸》教案
一、導(dǎo)入電視劇（圖片）:：鐵齒銅牙紀(jì)曉嵐 二、 作者簡介紀(jì)昀，字曉嵐，清代著 名學(xué)者,生性詼諧風(fēng)趣，任《四庫全書》（分古今圖書為經(jīng)、史、子、集四檔，總名為“四庫全書”）總纂官，著有《閱微草堂筆記》等?！堕單⒉萏霉P記》是紀(jì)昀晚年所作的一部文言筆記小說，題材以妖怪鬼狐為主，但于人事異聞、名物典故等也有記述，內(nèi)容相當(dāng)廣泛。三、感知課文 這篇課文講了一個(gè)故事：有一個(gè)廟靠近河，廟門倒塌之后，門旁的兩只石獅也掉到了河里。后來要修廟，決定要把石獅打撈上來。有人說，到下游去找，因?yàn)槭{被水沖走了，結(jié)果在下游沒找到。一個(gè)讀書人說，石獅肯定沉到沙泥里去了，因?yàn)槭^重，沙泥輕，結(jié)果在廟前的沙泥里也沒找到。一個(gè)老水手最后說，這兩個(gè)石獅在上游，結(jié)果果然在上游打撈到了。 怎么會(huì)到上游去呢？閱讀完課文后我們便知道了。反復(fù)朗讀，讀準(zhǔn)字音
部編版語文八年級(jí)上冊(cè)《中國石拱橋》教案
目標(biāo)導(dǎo)學(xué)四：揣摩語言，把握說明效果為了準(zhǔn)確地說明事物，說明文很講究用語的分寸。請(qǐng)品味下面的語句，回答括號(hào)內(nèi)的問題。1．石拱橋在世界橋梁史上出現(xiàn)得比較早。(“比較”一詞去掉行嗎？)明確：不行，“比較”程度較輕，是與其他橋梁比較而言，這樣表達(dá)比較準(zhǔn)確。2．這種橋不但形式優(yōu)美，而且結(jié)構(gòu)堅(jiān)固。(“不但”“而且”能否刪去？“結(jié)構(gòu)堅(jiān)固”“形式優(yōu)美”能否調(diào)換順序？)明確：“不但”“而且”不能刪去，如果刪去，它們之間的關(guān)系就變成了并列關(guān)系。先說外觀，再說功能，符合人們的認(rèn)識(shí)邏輯。并且對(duì)于橋來說，其實(shí)用價(jià)值遠(yuǎn)遠(yuǎn)重于形式，所以二者不能調(diào)換順序。3．《水經(jīng)注》里提到的“旅人橋”，大約建成于公元282年，可能是有記載的最早的石拱橋了。(“大約”“可能”“有記載的”有什么表達(dá)效果？)明確：“大約”“可能”都表示不確定，只是推測(cè)的情況?！坝杏涊d的”使話語的根據(jù)更具可靠性。
中學(xué)生心理健康教育主題班會(huì)教案
五、活動(dòng)背景：健康的心靈是我們幸福的源泉，只有接納自己、喜歡自己、充滿自信才有健康的心靈。然而，隨著社會(huì)的發(fā)展，中學(xué)生中存在著許多的心理健康問題。為更好地對(duì)中學(xué)生進(jìn)行心理健康教育、更好地優(yōu)化學(xué)生的心理素質(zhì)，促進(jìn)學(xué)生的心理健康成長。更好地引導(dǎo)同學(xué)們積極關(guān)注自我發(fā)展，自覺維護(hù)和提升心理健康水平，讓同學(xué)們的心理朝著陽光健康的方向發(fā)展，我們特開展以“心靈護(hù)航，快樂成長”為主題的中學(xué)生心理健康教育主題班會(huì)
北師大初中七年級(jí)數(shù)學(xué)上冊(cè)頻數(shù)直方圖教案2
［師］同學(xué)們想一想，你同父母一起去商店買衣服時(shí)，衣服上的號(hào)碼都有哪些，標(biāo)志是什么？［生］我看到有些衣服上標(biāo)有M、S、L、XL、XXL等號(hào)碼.但我不清楚代表的具體范圍.適合什么人穿.但肯定與身高、胖瘦有關(guān).［師］這位同學(xué)很善動(dòng)腦，也愛觀察. S代表最小號(hào)，身高在150~155 cm的人適合穿S號(hào).M號(hào)適合身高在155~160 cm的人群著裝…….廠家做衣服訂尺寸也并不是按所有人的尺寸定做，而是按某個(gè)范圍分組批量生產(chǎn).如何確定組距與組數(shù)呢？分組組數(shù)的確定，不僅與數(shù)據(jù)多少有關(guān)，還與數(shù)據(jù)的取值情況有關(guān).在實(shí)際決定組數(shù)時(shí)，常有一個(gè)嘗試過程：先定組距，再計(jì)算出相應(yīng)的組數(shù).看看這個(gè)組數(shù)是否大致符合確定組數(shù)的經(jīng)驗(yàn)法則.在嘗試中，往往要比較相應(yīng)于幾個(gè)組距的組數(shù)，然后從中選定一個(gè)較為合適的組數(shù).我們一起看下表：小亮的做法.
北師大初中八年級(jí)數(shù)學(xué)下冊(cè)分式的乘除法教案
通常購買同一品種的西瓜時(shí)，西瓜的質(zhì)量越大，花費(fèi)的錢越多，因此人們希望西瓜瓤占整個(gè)西瓜的比例越大越好．假如我們把西瓜都看成球形，并把西瓜瓤的密度看成是均勻的，西瓜的皮厚都是d，已知球的體積公式為V＝43πR3(其中R為球的半徑)，求：(1)西瓜瓤與整個(gè)西瓜的體積各是多少？(2)西瓜瓤與整個(gè)西瓜的體積比是多少？(3)買大西瓜合算還是買小西瓜合算？解析：(1)根據(jù)體積公式求出即可；(2)根據(jù)(1)中的結(jié)果得出即可；(3)求出兩體積的比即可．解：(1)西瓜瓤的體積是43π(R－d)3，整個(gè)西瓜的體積是43πR3；(2)西瓜瓤與整個(gè)西瓜的體積比是43π（R－d）343πR3＝（R－d）3R3；(3)由(2)知，西瓜瓤與整個(gè)西瓜的體積比是（R－d）3R3<1，故買大西瓜比買小西瓜合算．方法總結(jié)：本題能夠根據(jù)球的體積，得到兩個(gè)物體的體積比即為它們的半徑的立方比是解此題的關(guān)鍵．
