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新人教版高中英語選修2Unit 4 Reading for writing教學(xué)設(shè)計
假定你是英國的Jack，打算來中國旅行，請你給你的中國筆友李華寫一封信，要點如下：1．你的旅行計劃：北京→泰山→杭州；2．征求建議并詢問他是否愿意充當(dāng)你的導(dǎo)游。注意：1.詞數(shù)80左右(開頭和結(jié)尾已給出，不計入總詞數(shù))；2．可以適當(dāng)增加細節(jié)，以使行文連貫。參考詞匯：故宮 the Forbidden City；泰山 Mount TaiDear Li Hua，I'm glad to tell you that 'm going to visit China.First，I am planning to visit Beijing，the capitalof China，where I am looking forward to enjoying the Great Wall，the Forbidden City and somebeautiful parks.Then I intend to go to visit Mount Tai in Shandong Province.I've heard that it is one ofthe most famous mountains in China and I can't wait to enjoy the amazing sunrise there.After that，I amalso going to Hangzhou.It is said that it is a beautiful modern city with breathtaking natural sights，among which the West Lake is a well- known tourist attraction.What do you think of my travel plan? Will you act as my guide? Hope to hear from you soon.
新人教版高中英語選修2Unit 4 Using langauge-Listening教學(xué)設(shè)計
The theme of the listening section is " talking about scenery and culture along a journey."The part is designed to further lead the students to understand Canadian natural geography and social environment, and integrated into the cultural contrast by mentioning the long train journey from Beijing to Moscow routes. On this basis, the part activates students related travel experience, lets the student serial dialogue, guides the student to explore further the pleasure and meaning of the long journey, and Chinese and foreign cultural comparison.The part also provides a framework for the continuation of the dialogue, which is designed to provide a framework for students to successfully complete their oral expressions, and to incorporate an important trading strategy to end the dialogue naturally.1. Help students to understand and master some common English idioms in the context, and experience the expression effect of English idioms.2. Guide the students to understand the identity of different people in the listening context, and finish the dialogue according to their own experience.3. Instruct the students to use appropriate language to express surprise and curiosity about space and place in the dialogue, and master the oral strategy of ending the dialogue naturally.1. Instruct students to grasp the key information and important details of the dialogue.2. Instruct students to conduct a similar talk on the relevant topic.
新人教版高中英語選修2Unit 5 Learning about Language教學(xué)設(shè)計
The purpose of this section of vocabulary exercises is to consolidate the key words in the first part of the reading text, let the students write the words according to the English definition, and focus on the detection of the meaning and spelling of the new words. The teaching design includes use English definition to explain words, which is conducive to improving students' interest in vocabulary learning, cultivating their sense of English language and thinking in English, and making students willing to use this method to better grasp the meaning of words, expand their vocabulary, and improve their ability of vocabulary application. Besides, the design offers more context including sentences and short passage for students to practice words flexibly.1. Guide students to understand and consolidate the meaning and usage of the vocabulary in the context, 2. Guide the students to use the unit topic vocabulary in a richer context3. Let the students sort out and accumulate the accumulated vocabulary, establishes the semantic connection between the vocabulary,4. Enable students to understand and master the vocabulary more effectivelyGuiding the Ss to use unit topic words and the sentence patterns in a richer context.Step1: Read the passage about chemical burns and fill in the blanks with the correct forms of the words in the box.
新人教版高中英語選修2Unit 5 Reading and thinking教學(xué)設(shè)計
The theme of this activity is to learn the first aid knowledge of burns. Burns is common in life, but there are some misunderstandings in manual treatment. This activity provides students with correct first aid methods, so as not to take them for granted in an emergency. This section guides students to analyze the causes of scald and help students avoid such things. From the perspective of text structure and collaborative features, the text is expository. Expository, with explanation as the main way of expression, transmits knowledge and information to readers by analyzing concepts and elaborating examples. This text arranges the information in logical order, clearly presents three parts of the content through the subtitle, accurately describes the causes, types, characteristics and first aid measures of burns, and some paragraphs use topic sentences to summarize the main idea, and the level is very clear.1. Guide students to understand the causes, types, characteristics and first aid methods of burns, through reading2. Enhance students’ ability to deal withburnss and their awareness of burns prevention3. Enable students to improve the ability to judge the types of texts accurately and to master the characteristics and writing techniques of expository texts.Guide students to understand the causes, types, characteristics and first aid methods of burns, through readingStep1: Lead in by discussing the related topic:1. What first-aid techniques do you know of ?CPR; mouth to mouth artificial respiration; the Heimlich Manoeuvre
新人教版高中英語選修2Unit 5 Using langauge-Listening教學(xué)設(shè)計
The theme of this section is to learn how to make emergency calls. Students should learn how to make emergency calls not only in China, but also in foreign countries in English, so that they can be prepared for future situations outside the home.The emergency telephone number is a vital hotline, which should be the most clear, rapid and effective communication with the acute operator.This section helps students to understand the emergency calls in some countries and the precautions for making emergency calls. Through the study of this section, students can accumulate common expressions and sentence patterns in this context. 1.Help students accumulate emergency telephone numbers in different countries and learn more about first aid2.Guide the students to understand the contents and instructions of the telephone, grasp the characteristics of the emergency telephone and the requirements of the emergency telephone.3.Guide students to understand the first aid instructions of the operators.4.Enable Ss to make simulated emergency calls with their partners in the language they have learned1. Instruct students to grasp the key information and important details of the dialogue.2. Instruct students to conduct a similar talk on the relevant topic.Step1:Look and discuss:Match the pictures below to the medical emergencies, and then discuss the questions in groups.
新人教版高中英語選修3Unit 1 Art教案
[2] An important breakthrough…was… [3] Another innovation was … [4] the emphasis increasingly shifted from…to… [5] New ideas and values gradually replaced… [6] While his paintings still had religious themes… … T: All these expressions serve to show how Western painting has developed. Some of them share similar structure but with varied use of words, which makes the text vivid and more readable. 【設(shè)計意圖】主題類語言整理有助于學(xué)生類化語言應(yīng)用，提高語言輸出的豐富性。處理完文本內(nèi)容信息后，進入語篇信息處理，進行主題相關(guān)的詞塊歸類。引導(dǎo)學(xué)生快速閱讀，尋找表達相同主題(發(fā)展或者藝術(shù))的詞和短語，再根據(jù)詞性、用法和結(jié)構(gòu)進行歸類，儲備主題相關(guān)詞匯，豐富語言儲備，提升語言素養(yǎng)。 Assignment: Go online to gather more information about Chinese painting and write a short history of it. 【設(shè)計意圖】結(jié)合所學(xué)，遷移運用，根據(jù)實際語境，進行模仿性運用。在此過程中，學(xué)生嘗試借鑒已學(xué)的語言、內(nèi)容、語篇結(jié)構(gòu)和寫作手法來建構(gòu)新文本，實現(xiàn)語篇輸出，同時關(guān)注中西藝術(shù)文化的差別，加深對優(yōu)秀文化的認同，培養(yǎng)文化意識。
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 本活動為實現(xiàn)課時目標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)計意圖】 步驟1旨在預(yù)測和驗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)情況融入對語篇人稱多次轉(zhuǎn)換的思考。
新人教版高中英語選修3Unit 4 Adversity And Courage教案
本活動旨在落實課時目標3。 The Student Union is looking for three students for a 3-week voluntary program in Guizhou province. The volunteers have got to be high school students, with a persevering personality and experiences in overcoming adversity. The volunteers need to stay, eat and teach with 20 pupils in a small school up on the hill of a village. There are no facilities but desks and a blackboard in the school. And there is no take-away food to be bought anywhere; the only way to feed yourself is to cook. You’re interested in applying. Write your application letter introducing what adversity you have ever overcome and how persevering you are as well as what you want to do when at work. Dear Student Union,【設(shè)計意圖】此任務(wù)旨在遷移一、二課時所學(xué)，解決實際問題。學(xué)生對比自己經(jīng)歷過的挑戰(zhàn)或挫折，寫信給學(xué)生會申請前往貴州擔(dān)任短期支教教師，把個人以前是怎么戰(zhàn)勝挫折的經(jīng)過書寫出來。結(jié)合所學(xué)，遷移創(chuàng)新，分析解決自身實際問題，在真實情境中學(xué)生通過仿寫進行主題語言的精確輸出。完成任務(wù)的過程中，能較多地使用已學(xué)語言、內(nèi)容、結(jié)構(gòu)和寫作手法來描述自己面對挫折的處理方式、態(tài)度和應(yīng)有的品質(zhì)，近一步激發(fā)學(xué)生樹立正確的價值觀，學(xué)會逆境出人才，堅忍不拔，從容不迫，又做到謙讓、分享和合作。課后學(xué)生修正習(xí)作，再次提交。
新人教版高中英語選修3Unit 5 Poems教案
本單元閱讀文本介紹了幾種簡單的英語詩歌形式，旨在讓學(xué)生能理解和欣賞英語詩歌的美，包括形式美、內(nèi)容美、意義美，培養(yǎng)審美情趣，并從作品的意義美中獲得積極的人生態(tài)度和價值觀念啟示。 該文本是一則典型的說明性文本，用簡單易懂的語言向英語詩歌的初學(xué)者們介紹了五種比較簡單的英語詩歌形式。文題“A Few Simple Forms of English Poems”是整個文本的核心話題。正文內(nèi)容共七段，按“總—分—總”建構(gòu)。第一段為總起段，概述了英語詩歌的創(chuàng)作原因以及主要特點，涉及了形式、內(nèi)容、意義等方面賞析英語詩歌的幾個主要維度；第二段至第六段分別介紹了童謠、清單詩、五行詩、俳句和唐詩五種英語詩歌形式；第七段收尾，鼓勵讀者嘗試英語詩歌創(chuàng)作。 在進行文本教學(xué)設(shè)計時，要引導(dǎo)學(xué)生梳理關(guān)于與詩歌要素和詩歌賞析有關(guān)的話題類語言，既包括format、rhythm、subject、image等名詞，也包括have a strong rhythm、be made up of、contain、consist of、convey這樣的動詞和動詞短語。
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 本活動為實現(xiàn)課時教學(xué)目標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 3 Reaching Out Across the Sea教案
本活動旨在落實課時目標3。 Think about the following questions and talk about your own attitude in pairs.Q1: As for this topic，what impresses you the most in the passage?Q2: What do you think of the future of China’s further exploration in sea? Are you in favor of the further exploration？Why or why not? 【設(shè)計意圖】該活動是一個完全開放性的活動，每個學(xué)生都會有不同的答案。運用遷移所學(xué)，自由口頭表達自己對海洋探索的態(tài)度。對于中國海洋探索的未來，每個人的想法是不一樣的，有樂觀，有擔(dān)憂，有認為值得投入，也有認為不值得付出太大代價，這里給學(xué)生自由表達的空間只要學(xué)會有支撐自己觀點的事實就可以了，進一步培養(yǎng)學(xué)生批判性思維和正確的價值觀。 Assignment: 此任務(wù)旨在遷移一、二課時所學(xué)，培養(yǎng)學(xué)生辯證分析問題的能力。 Write about your idea of the future of China’s sea exploration. And add your attitude towards the effort China have made in sea exploration. You’re expected to use the language and the writing technique learnt in the passage.
新人教版高中英語選修4Unit 4 Sharing教案
【核心素養(yǎng)提升點】學(xué)會將抽象信息進行可視化表達，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】提高信息處理能力、分析和歸納能力，包容異國文化、擴展國際視野。 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“It was such a privilege to have spent a day with Tombe’s family”這句話的理解，體驗志愿者生活的偉大。 【核心素養(yǎng)提升點】學(xué)會對信息的綜合和歸納，從而理解作者所表達的觀點。 Activity4: Summarize the change of Jo's feelings
新人教版高中英語選修4Unit 5 Language Your Career教案
本單元閱讀文本向中學(xué)生推薦職業(yè)能力測試(Career Aptitude Test)，旨在建議學(xué)生利用職業(yè)傾向測試來發(fā)現(xiàn)自己更感興趣、更有潛力的學(xué)習(xí)或職業(yè)方向，并規(guī)劃自己的未來職業(yè)。 本文采用了建議性文本，全篇從職業(yè)生涯的重要意義講起，針對中學(xué)生對職業(yè)規(guī)劃比較迷茫的現(xiàn)狀，提出了職業(yè)傾向測試這一建議。全文共七段，其中第一段和第二段為第一部分，其余五段為第二部分。第一部分論述職業(yè)的重要性和職業(yè)生涯規(guī)劃的最佳時間是在校期間，第二部分提出解決職業(yè)選擇困惑可以通過完成職業(yè)能力測試，介紹了不同種類的職業(yè)傾向測試，結(jié)合圖表詳細說明其中一種操作步驟，并提醒職業(yè)建議也基于學(xué)歷和經(jīng)驗，最后一段概括論述，建議學(xué)生通過職業(yè)能力測試這一有效的工具，找到自己真正熱愛的事物。 在文本教學(xué)設(shè)計時，要幫助學(xué)生梳理有關(guān)職業(yè)的話題語言。閱讀策略層面，指導(dǎo)學(xué)生通過學(xué)習(xí)圖表和圖形，在有限的空間內(nèi)獲取廣泛信息，如閱讀圖表標題，圖表上的標簽，X軸Y軸上的數(shù)據(jù)所指。
人教版高中地理選修1人類對宇宙的探索教案
通過觀看課件引導(dǎo)學(xué)生對各種航天器的了 解,使學(xué)生直觀的了解宇宙環(huán)境的特點.體現(xiàn)教師為主導(dǎo)學(xué)生的主體的教學(xué)理念.培養(yǎng)學(xué)生歸納能力.通過分組討論澄清知識盲點―我國航天事業(yè)接近并超過發(fā)達國家.要求學(xué)生根據(jù)前后聯(lián)系自己得出結(jié)論.體現(xiàn)學(xué)生主體設(shè)疑,引進熱點主要是要學(xué)生明白:宇宙環(huán)境保護的重要性.例題練習(xí)2004年高考大綜合地36題展示習(xí)題學(xué)生做讓學(xué)生走近高考了解高考（三）課堂小結(jié)師生共同完成知識點總結(jié)、教師做思想方法的總結(jié)教師引導(dǎo)、學(xué)生說知識點使學(xué)生對知識有整體掌握.使學(xué)生能堅持用科學(xué)的觀點分析發(fā)現(xiàn)各種新問題.（四）布置作業(yè)用發(fā)展的觀點談?wù)剬χ袊訌姾教焓聵I(yè)發(fā)展的看法.鞏固所學(xué)知識:聯(lián)系實際為下節(jié)課學(xué)習(xí)做鋪墊.板書設(shè)計世界宇宙新探索中國航天事業(yè)的發(fā)展宇宙資源開發(fā)宇宙資源宇宙環(huán)境問題的產(chǎn)生宇宙環(huán)境保護
人教版高中地理選修5防災(zāi)與減災(zāi)教案
（一）自然災(zāi)害監(jiān)測系統(tǒng)1．概念：自然災(zāi)害監(jiān)測系統(tǒng)是由國家、區(qū)域及地方等各級組織，通過不同平臺對自然災(zāi)害進行監(jiān)測和分析的網(wǎng)絡(luò)系統(tǒng)。2．作用：災(zāi)前預(yù)警、災(zāi)中跟蹤、災(zāi)后評估以及提出減災(zāi)決策方案3．世界和我國災(zāi)害監(jiān)測系統(tǒng)的發(fā)展情況①已經(jīng)形成了遍布世界各地、相互交織的災(zāi)害監(jiān)測和預(yù)警網(wǎng)絡(luò)。②我國已經(jīng)運用現(xiàn)代科學(xué)技術(shù)建立起各種自然災(zāi)害監(jiān)測系統(tǒng)（二）遙感技術(shù)在自然災(zāi)害監(jiān)測中的作用1．遙感（RS）技術(shù)的特點：觀測范圍廣、信息獲取量大、獲取速度快、實時性好和動態(tài)性強等。從空間尺度看，遙感具有全球觀測能力，可從多波段、多時相和全天候角度獲得全球自然災(zāi)害的觀測數(shù)據(jù)；從時間尺度看，在遙感平臺上能夠?qū)Φ厍蜻M行同步觀測，可獲得地球表層及其瞬間變化的災(zāi)害信息。
人教版高中地理選修1月球和地月系教案
月球?qū)Φ厍虻囊饬x月球與地球形影相隨，關(guān)系密切。月球?qū)Φ厍虻挠绊?，主要有以下幾方面?．地球上夜晚的自然照明，主要靠月亮。2．遠在古代，人們就根據(jù)月相變化的周期，編訂歷法。我國農(nóng)歷月份的安排，是以月相變化 周期為標準的。農(nóng)歷規(guī)定朔為初一，這樣，望就在十五日或十六日。我國人民的傳統(tǒng)節(jié)日，像春節(jié)、中秋節(jié)就是按農(nóng)歷的月日計算安排的。3．由于地球表面各處所受月球和太陽引力的不同，地球上的水體產(chǎn)生了明顯的潮汐現(xiàn)象。4．月球是人類星際航行的第一站。已知月球表面有多種寶貴礦藏；重力較??；沒有大氣層，利用太陽能的條件較好。如何利用月球的特殊環(huán)境，開發(fā)月球的資源，以及如 何利用月球作“碼頭”，使人類更好地研究宇宙，這將是月地關(guān)系的新篇章。
人教版高中地理選修1月相和潮汐變化教案
5.對土星五號火箭和登月艙的質(zhì)疑現(xiàn)代航天飛機只能把20噸載荷送上低軌，而當(dāng) 年的土星五號卻能輕而易舉地把100噸以上載荷送上地球軌道，將幾十噸物體推出地球重力圈，為什么后來卻棄而不用，據(jù)說連圖紙都沒有保存下來？6.溫度對攝影器材的影響月面白天可達到121°C，據(jù)圖片看，相機是露在宇航服外而沒有采用保溫措施的。膠卷在66°C就會受熱卷曲失效，怎么拍得了照片？這些人士認為，對以上這一切美國政府一直沒個 交代，而知情者由于擔(dān)心生活和安全受到影響，甚至可能直接遭到了脅迫，至今對此沉默不言。但相信不久的將來，誕生于美蘇太空競賽年代的“登月騙局”定會水落石出。反駁不過，也有許多人認為“阿波羅”登月計劃不可能造假：首先因為該計劃當(dāng)時是在全球?qū)崨r轉(zhuǎn)播的，近億人親眼看到。另外，宇航員還從月球帶回了一些實物，如巖石。
人教版高中地理選修1地形的變化教案
學(xué)習(xí)目標1.了解外力作用的表現(xiàn)形式，理解風(fēng)化作用、侵蝕作用、搬運作用和沉積作用的概念和種類，以及它們所形成的各種地形；培養(yǎng)學(xué)生觀察、分析地理景觀圖的能力和動手做實驗的能力。2.了解外力作用各表現(xiàn)形式之間的關(guān)系，理解它們是如何推動地表形態(tài)的演化的，培養(yǎng)我們學(xué)生地理事物之間相互聯(lián)系的觀點，從而樹立辯證唯物主義的觀點。學(xué)習(xí)重點1.風(fēng)化、侵蝕、搬運、沉積作用所形成的不同的地表形態(tài)。2.外力作用各表現(xiàn)形式相互之間的關(guān)系。學(xué)習(xí)難點1.外力作用各表現(xiàn)形式所形成的不同的地表形態(tài)。2.培養(yǎng)學(xué)生樹立正確的人地關(guān)系的觀點。學(xué)習(xí)過程：1、看課本討論回答：外力作用①能量來源 ②表現(xiàn)形式 ③對地貌的影響2、流水、風(fēng)力作用及其形成的地貌
人教版高中地理選修1板塊構(gòu)造學(xué)說教案
【啟發(fā)想象 】能否將剛才講的內(nèi)容用一個游泳動作形容一下？這好像蛙泳動作。我們大家一起做：熔巖冒出（雙手合十向上）→推向兩邊（雙手向兩側(cè)分開）→遇陸俯沖（雙手往下）→重熔再生（雙手相向合并向上）?！拘〗Y(jié)板書】二、海底擴張學(xué)說前面我們學(xué)習(xí)了兩個假說，整理一下已知條件：事實證明大陸是在漂移的，如歐洲與美洲的距離在擴張，但是漂移的動力不足；海底是不斷擴張的，有生長與消亡。能否在前人研究的基礎(chǔ)上，提出更準確更合理的假設(shè)呢？一個新的理論誕生了，它是目前最盛行、最活躍的全球構(gòu)造理論【板書】三、板塊構(gòu)造學(xué)說1．板塊概念學(xué)生讀書?！締l(fā)提問】板塊“漂移”與大陸“漂移”的位置有何不同？學(xué)生回答。板塊漂移是指巖石圈漂在軟流層上，大陸漂移發(fā)生在地殼兩層之間?！咎釂枴堪鍓K是如何劃分的？讀圖用半分鐘記下六大板塊的位置和名稱（提示：按大洲和大洋名稱記憶）。
人教版高中地理選修1太陽和太陽系教案
彗星簡介：（1）云霧狀的獨特外貌，質(zhì)量很小；（2）主要由冰物質(zhì)構(gòu)成（含塵埃、水、甲烷、二氧化碳等），有人稱它為“臟雪球”；（3）結(jié)構(gòu)分彗核、彗發(fā)、彗尾（分離子尾、塵埃尾），彗星在遠離太陽時，只有一個冰凍的彗核，當(dāng)行進太陽時，組成物質(zhì)升華而形成彗發(fā)，在太陽風(fēng)的吹拂下，背向太陽的一側(cè)出現(xiàn)彗尾，遠離太陽時，彗尾消失，尾永遠背向太陽；（4）目前已經(jīng) 發(fā)現(xiàn)了1600多顆彗星，最著名的就是哈雷彗星，1985～1986 年，曾回歸；（5）彗星的公轉(zhuǎn)周期各不相同，相差極大，有的幾十年，有的幾百年，哈雷彗星的公轉(zhuǎn)周期為76年。學(xué)生討論回答，然后速讀課文“流星體”?！締l(fā)引導(dǎo)】行星際空間是否是“真空”狀態(tài)？行星際空間分布著極其稀薄的氣體和塵埃，稱為行星際物質(zhì)，行星際物質(zhì)的來源——太陽風(fēng)、星際沖撞……