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新人教版高中英語必修1Unit 1 Teenage Life-Reading and Thinking教案
【教材分析】The topic of this unit is about teenage life, which belongs to the theme context of “humans and oneself”.As teenagers who shoulder the responsibility of “Chinese great dream”, they must fully know themselves, including their strengths, weaknesses and challenges etc. They are supposed to improve themselves continuously and readily study their subjects, and thus foster their strategies and confidence in lifelong studies.This period is entitled the freshmen challenges, which mainly concerns some big challenges for new students in Senior high school. In this period, a teacher should lead students to find out what their challenges are and guide them to figure out how to crack the challenges and better themselves. More importantly, a teacher should instruct students to absorb new language points and appreciate the language. Besides, a teacher must instruct students to acquire some skills concerning reading efficiently and inspire them to talk more about their new school life, especially their new problems and solutions both at school and in life.【教學目標與核心素養(yǎng)】1. Enable students to acquire the basic usage of the new words and expressions concerning the freshmen challenges and learn to use them flexibly.2. Enable students to have a good understanding of the freshmen challenges in the new senior high school which is quite different from junior middle school.3. Develop students’ sense of cooperative learning and individual thinking capability. 4. Develop students’ different learning skills to solve different reading comprehensive problems.
新人教版高中英語必修1Unit 4 Natural Disasters-Discovering Useful Structures教案
【教材分析】This teaching period mainly deals with the grammar: the restrictive relative clauses.This period carries considerable significance to the cultivation of students’ writing competence and lays a solid foundation for the basic appreciation of language beauty. The teacher is expected to enable students to master this period thoroughly and consolidate the knowledge by doing some exercise of good quality.【教學目標與核心素養(yǎng)】1. Get students to have a good understanding of the basic usages of the restrictive relative clauses.2. Enable students to use the restrictive relative clauses flexibly.3. Develop students’ speaking and cooperating abilities.4. Strengthen students’ great interest in grammar learning.【教學重難點】How to enable students to have a good understanding of the restrictive relative clauses, especially the uses of the relative words such as which, that, who, whom.【教學過程】Step1: 語法知識呈現(xiàn)定語從句（一）—關(guān)系代詞的用法在復合句中, 修飾名詞或代詞的從句叫定語從句。定語從句通常由關(guān)系代詞或關(guān)系副詞引導，說明事物的具體信息，從句位于被修飾詞之后。被定語從句修飾的詞叫先行詞，引導定語從句的詞叫關(guān)系詞，關(guān)系詞指代先行詞，并在定語從句中充當成分。關(guān)系詞有兩種：關(guān)系代詞who, whom ,whose, that, which, as和關(guān)系副詞when, where, why。
新人教版高中英語必修1Unit 5 Languages Around the World-Reading for Writing教案
Step 3: Read to sum upRead it again and sum up the problems of the three students, and then write down the advice that was given from others.Step 4: Work in pairs. List your learning problems in English and brainstorm some useful advice.Useful expressions ? I don't know how to…... Is a big difficulty for me. I cannot ...? You might try …. It's very important to…? I have no idea how/what .My biggest problem is .... ? I (also) have trouble with. My advice is …. This worked for me.? l cannot understand the teachers’ English in class.Step 5 Homework：為提高我校學生的英語口語水平，我們將舉辦英語演講比賽(English- speaking contest)，請你根據(jù)下面的信息，以學生會(the Students‘ Union)的名義寫一份海報，歡迎全校同學參加，屆時特邀本校美籍教師史密斯先生頒獎。? 報名時間 9月30日以前(報名:signup)? 報名地點 學生會辦公室? 比賽時間 10月9日晚7:00~9:00? 比賽地點 學校大會議室? 獎勵 前8名
新人教版高中英語必修1Welcome Unit-Reading for Writing教案
教學目標知識目標：讓學生更好理解如何恰當?shù)貙懸粋€人的信息介紹，并能讓學生熟練地使用一些寫作技能。能力目標：培養(yǎng)學生的寫作能力和團隊協(xié)作能力。情感目標：提升學生對寫作的興趣。教學重難點 教學重點：如何能讓學生更好地理解個人信息介紹。教學難點：如何能讓學生通過適當?shù)厥褂靡恍懽骷寄軄韺懸黄^好的個人信息介紹。教學準備 多媒體、黑板、粉筆一、Pre-class1. Greetings2. Leading-inAsk students how to write a profile. What kinds of aspects should be included? The teacher asks students to discuss the topic with each other and put forward to much more ideas about the answer.二、While-class1. The teacher lets students to read the student profiles on Page 8 silently and then asks students to discuss the questions below.1. What is Ann like? How do you know?2. What are Thando’s hobbies?3. Where does Thando come from?4. What is Thando’s dream?5. What does “You will never see me without a book or a pen” mean?
新人教版高中英語必修2Unit 2 Wildlife Protection-Discovering Useful Structure教案二
2．表示現(xiàn)階段正在進行的被動動作(該動作在說話的瞬間未必正在進行)。Many interesting experiments are being carried out these days.(說話時，并不一定正在進行)3．表示一種經(jīng)常性的被動行為，常和always，constantly 等表示頻度的副詞連用，這種用法常常帶有贊揚或厭惡的感情色彩。He is always being praised by the leader.4．表示按計劃或安排主語將要承受謂語動詞所表示的動作(僅限于少數(shù)及物動詞)。A party is being held tonight.Step 4 Special cases1.像take care of, look after, talk about, think of等動詞與介詞構(gòu)成的短語用于現(xiàn)在進行時的被動語態(tài)時, 其中的介詞不可省略。The ways to stop illegally hunting are being talked about. 2．可與部分情態(tài)動詞連用，表示對正在發(fā)生的事情的推測。She may be being punished by her mother.3．有時可表示按計劃或安排將要進行的一個被動動作。A celebration is being held this weekend for his success.4．某些表示“狀態(tài)、心理活動、存在”等的動詞，如have，want，need，love，一般不用現(xiàn)在進行時的被動語態(tài)，而常用一般現(xiàn)在時的被動語態(tài)。With the population increasing，more land is needed.5．“be＋under/in＋n.”可表示現(xiàn)在進行時的被動意義。My computer is under repair.＝My computer is being repaired.
新人教版高中英語必修2Unit 1 Cultural Heritage-Reading For Writing教案
This report is short, concise and has typical news content and language features. The title uses the verb phrases, embodying the characteristics of being concise and general. The introduction is the first two sentences in the first paragraph, describing the general situation of the cultural heritage protection project, including time, place, characters, events and other news elements, so that readers can see the main points of the news report at a glance. The main body is the second and third paragraphs, which report the important historical and cultural value of Mogao Grottoes and the production of Mogao Grottoes Material digital photos, which are of great significance to the inheritance of historical culture and the promotion of international cultural understanding, exchange and cooperation. Direct citation is used in the report, as well as background introduction and other news writing techniques.1. Get students to have a good understanding of some features about a news report by reading the text.2. Instruct students to write a summary about a news report properly using some newly acquired writing skills in this period.3. Develop students’ writing and cooperating abilities.4. Strengthen students’ great interest in writing discourses.1. Stimulate students to have a good understanding of how to a summary about a news report 2. Cultivate students to write a news report properly and concisely.Step 1: Lead in Do you think it is necessary for us to circulate our cultural heritage to the world? Why or why not?Do we need to learn more about other countries’ cultural heritage? Why or why not?Step 2: Read to discover details concerning the main body of the news report.
新人教版高中英語必修2Unit 2 Wildlife Protection-Reading For Writing教案一
1. 標題首先根據(jù)海報的特點、格式寫明標題。海報中往往把內(nèi)容作為大標題。例如: Save the earth, Save the birds。2. 正文部分不同的海報其正文部分的側(cè)重點不同。對于介紹性的海報, 首先要引出話題, 其次列出原因, 最后是總結(jié)。對于宣傳類的海報, 要寫明具體內(nèi)容, 如: 活動內(nèi)容, 地點以及參加活動的注意事項, 主持或舉辦單位等。1. 圖片: 要選擇引人注目的圖片, 與主題要相關(guān), 色彩明亮。話題句式 1. It is a treasure of our country. 它是我國的國寶。2. Believe it or not, at present only several thousand pandas exist in the world. 信不信由你, 目前世界上僅現(xiàn)存幾千只熊貓。 3.It’s because of human activities that tigers are endangered. 正是因為人類的活動, 老虎處于瀕危的狀態(tài)。4. Many wild animals are in danger of dying out. 很多野生動物面臨著滅絕的危險。 5. The government has taken effective measures to protect them. 政府已采取有效的措施來保護它們。6. People should raise the awareness of the protection of wild animals. 人們應(yīng)該提高保護野生動物的意識。 7. It’s amazing that there are merely less than 1, 000 finless porpoises living in China. 非常令人吃驚, 目前中國僅有不足1 000只江豚。
新人教版高中英語必修2Unit 4 History and Traditions-Listening＆Speaking＆Talking教案一
This unit is about history and traditions. From the opening page, we can know that this unit will introduce the history and traditions around the world. As Marcus Garvey says “A people without the knowledge of their past history, origin and culture is like a tree without roots”, it is important for students to realize the importance and value of knowing the history and traditions and their further meanings. And this part ( listening and speaking ) is divided into two parts: Part A---share views on historic sites, Part B ---talk about a visit to a historic tourist destination. By talking with a foreigner, the speakers introduce the historic attractions and their cultures. Part A is that William, a British student, who was going to visit the Confucius Temple and a Chinese student, Xiao Kong, who was going to the Confucius Temple to meet with the members of the research group, went together and exchanged their views on the Confucius Temple, Confucius, Confucius' descendants and Confucius' educational thoughts. Part B is a conversation between Xiao Yan, a youth hostel receptionist and Paul, a backpacker about the feelings and experience after visiting the Chinese famous tourist attraction Pingyao.1. Guide students to understand the content of listening texts in terms of the whole and key details; 2. Cultivate students' ability to guess the meaning of words in listening; discuss with their peers how to talk about historic spots and great person.3. Instruct students to use functional sentences of showing one’s excitement, surprise and disappointment.1. Guide students to understand the content of listening texts in terms of the whole and key details; 2. Cultivate students' ability to discuss with their peers the related topics.3. Enable students to use the functional items of showing one’s excitement, surprise and disappointment.
新人教版高中英語必修2Unit 4 History and Traditions-Discovering Useful Structure教案二
This teaching period mainly deals with grammar: The past participle is used as attributive and objective complement.1. Guide students to review the basic usages of the past participle used as attributive and objective complement.2. Lead students to learn to use some special cases concerning the past participle used as attributive and objective complement flexibly.3. Strengthen students’ great interest in grammar learning.1. Help students to appreciate the function of the past participle used as attributive and objective complement.2. Instruct students to write essays using the past participle used as attributive and objective complement.Step1:溫故而知新。Analyze the underlined phrases and then sum up the common usages of the past participles.1．(教材P41)They had castles built(build) all around England, and made changes to the legal system．2．(教材P42)They use the same flag, known(know) as the Union Jack，．．．3．(教材P42)Judy and I had our car parked(park) in an underground car park near Trafalgar Square, where we could get our car battery charged(charge)．Common points: f the past participle used as attributive and objective complement.Step 2:過去分詞作定語時的意義1．及物動詞的過去分詞作定語，在語態(tài)上表示被動；在時間上，常表示動作已經(jīng)發(fā)生或完成，有時也不表示時間性。Our teacher watched us doing the experiment and gave us a satisfied smile at last．我們的老師看著我們做實驗，最后給了我們一個滿意的微笑。The plan put forward at the meeting will be carried out soon．會上提出的計劃將很快被執(zhí)行。2．不及物動詞的過去分詞作定語，它不表示被動意義，只強調(diào)動作完成。Many little kids like gathering fallen leaves in the yard．
新人教版高中英語必修2Unit 4 History and Traditions-Listening＆Speaking＆Talking教案二
Listening and Speaking introduces the topic of “Take part in a youth project”. The listening text is an interview about "sharing views on historical sites". Through listening to a dialogue between Chinese and foreign students on the way to the Confucius Temple, students can understand their views on the Confucius Temple, Confucius, Confucius' descendants and Confucius' educational thoughts, so as to realize and think about the profound influence of Confucius and his thoughts on Chinese historical tradition. At the same time, the dialogue naturally integrates English idioms and mentions Shakespeare, the British playwright, so as to provide language materials and context for students to understand English idioms and related cultural allusions, as well as to compare Chinese and foreign cultures, which is helpful for students to understand and express the language such as history, tradition, culture and custom significant impact.Text analysis: listening text is a dialogue between a British student and a Chinese student when he goes to the Confucius Temple. When William, a British student, visited the Confucius Temple, he asked Xiao Kong, a Chinese student, for directions. Xiao Kong was just going to the Confucius Temple to meet with the members of the research group, so they went together and exchanged their views on the Confucius Temple, Confucius, Confucius' descendants and Confucius' educational thoughts. From the perspective of foreign tourists, this paper describes their thoughts on Confucius, the great son of Confucius, who had a profound impact on Chinese history and cultural tradition, and his education.Listening and Talking introduces a visit to a historic tourist destination. Tourism is a common way to understand a country's history, culture, and customs and so on. Students listen to the dialogue between Xiao Yan, a youth hostel Usher, and Paul, a backpacker, to learn about Pingyao's famous historical and cultural attractions and Paul's travel experience and experience as a foreign tourist.
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教案一
(4)Now we have heard a number of outstanding speeches ... 我們已經(jīng)聆聽了許多精彩的發(fā)言……(5)Because we wanted the nations of the world, working together, to deal with ... 因為我們希望全世界各國團結(jié)起來去應(yīng)對……(6)And if we do not act ... 如果我們不采取行動……(7)Now, I share the concerns that have been expressed ... 我也同意對于……表達的擔心(8)Let us show the world that by working together we can ... 讓我們告訴全世界，通過一起努力我們可以……(9)It is now time for us to ... 是時候我們……(10)And I have always wished that ... 我一直希望……(11)Thank you for letting me share this day with me.感謝你們和我共度這一天。實踐演練：假如你是高中生李華，你校將舉辦一次以“音樂”為主題的演講比賽，請你按照主題，寫下你的演講稿。注意：詞數(shù)100左右。First of all, thank you for listening to my speech. My topic is: love music like love yourself.Music is like the air we need to maintain our normal lives around us. You can't imagine how terrible a world without music would be. Movies and TV shows have no music, only dry conversations and scenes; mobile phones only vibrations; streets only noisy crowds; cafes, western restaurants only depressed meals. What a terrible world it is!As a student, I hope we all can enjoy the fun brought by music in our spare time. Instead of just listening to music, we can even make our own music. Let's enjoy the fun of music!Thanks again for your attention!
人教版高中地理必修1常見天氣系統(tǒng)教案
知識和技能 ⑴從圖片和簡易圖中，了解氣團（冷氣團、暖氣團）的概念；鋒的概念與分類；低壓（氣旋）、高壓（反氣旋）、高壓脊、低壓槽的概念。⑵從氣溫、氣壓、濕度、降水、風等幾方面分析各種天氣系統(tǒng)的形成及其氣流特點，并綜合出各種天氣系統(tǒng)控制下的天氣狀況過程與方法 ⑴讓學生能閱讀和簡單分析天氣圖，解釋天氣變化現(xiàn)象；⑵用案例說明氣象災(zāi)害發(fā)生的原因和危害；⑶結(jié)合我國常見的天氣系統(tǒng)說明其對人們生產(chǎn)和生活的影響情感、態(tài)度與價值觀激發(fā)學生探究天氣的形成和變化的興趣和動機，培養(yǎng)學生求真、求實的科學態(tài)度，提高地理審美情趣教學重點1.鋒面系統(tǒng)。(鋒面系統(tǒng):一是要區(qū)別冷暖鋒的成因，二是要掌握鋒面兩側(cè)的氣壓、溫度、濕度、風和天氣差異)2.低壓、高壓系統(tǒng)。（要掌握其成因、氣壓特征、氣流特征及其天氣特點四個方面。）
人教版高中地理必修1地球的圈層結(jié)構(gòu)教案
師：很好。由于存在地球大氣圈、地球水圈和地表的礦物，在地球上這個合適的溫度條件下，形成了適合于生物生存的自然環(huán)境。人們通常所說的生物，是指有生命的物體，包括植物、動物和微生物。據(jù)估計，現(xiàn)有生存的植物約有40萬種，動物約有110多萬種，微生物至少有10多萬種。據(jù)統(tǒng)計，在地質(zhì)歷史上曾生存過的生物約有5億～10億種之多，然而，在地球漫長的演化過程中，絕大部分都已經(jīng)滅絕了?，F(xiàn)存的生物生活在巖石圈的上層部分、大氣圈的下層部分和水圈的全部，構(gòu)成了地球上一個獨特的圈層，稱為生物圈。生物圈是太陽系所有行星中僅在地球上存在的一個獨特圈層。課堂小結(jié)：地球所有的外部圈層是相互滲透、相互影響，甚至相互重疊的，在太陽和人類生活的參與下，整個地球生機盎然；同時，它們起著保護地球的作用，可以減弱太陽和宇宙輻射對地表的影響，減少宇宙中的隕石對地球表面的撞擊。外部各圈中的物質(zhì)運動和循環(huán)，是促使地表物質(zhì)和形態(tài)演變的重要動力。
人教版高中地理必修1太陽對地球的影響教案
當時，不只發(fā)生了太陽風暴，同時還有其它的現(xiàn)象發(fā)生，導致災(zāi)難巨大。 如果，這些現(xiàn)象單獨地發(fā)生，結(jié)果就會是另外一個樣子。正是由于這些因素綜合起來，1859年的太陽風暴，才在人類歷史上留下了濃墨重彩的一筆。太陽磁暴開始干擾通信日本衛(wèi)星首個被“擊中”日本航天機構(gòu)29日聲明，受強烈的太陽磁暴影響，28日晚，日本“兒玉(Kodama)”通訊衛(wèi)星信號中斷。 據(jù)美聯(lián)社報道，在太陽黑子活動減弱后，“兒玉”通訊衛(wèi)星恢復正常運轉(zhuǎn)。 美歐研究人員28日發(fā)布新聞公告稱，太陽當天發(fā)生了一次強烈的耀斑爆發(fā)，預示著新一輪太陽風暴將在今后一兩天內(nèi)抵達地球，地球上的通信等設(shè)施可能會因此受到部分干擾。與這次耀斑爆發(fā)相伴，太陽表面還產(chǎn)生了一股強大的日冕物質(zhì)噴射，方向幾乎直沖地球。研究人員說，噴射產(chǎn)生的帶電粒子流正以約每小時750萬公里的速度奔地球而來，其與地球磁場作用后可能會形成比較強烈的地磁暴，使地球兩極出現(xiàn)極光，并可能對衛(wèi)星運行和通信等造成干擾。
人教版新課標高中物理必修1力的分解教案2篇
一、教材內(nèi)容經(jīng)全國中小學教材審定委員會2004年初審查通過，人教育出版社出版的普通高中課程標準實驗教科書《物理必修①》，第三章第5節(jié)內(nèi)容“力的分解”。二、教學目標1．知識與技能（1）理解分力的概念，理解力的分解是力的合成的逆運算，遵循平行四邊形定則。（2）初步掌握一般情況下力的分解要根據(jù)實際需要來確定分力的方向。（3）會用作圖法和直角三角形的知識求分力。（4）能區(qū)別矢量和標量，知道三角形定則，了解三角形定則與平行四邊形定則的實質(zhì)是一樣的。2．過程與方法（1）進一步領(lǐng)會“等效替代”的思想方法。（2）通過探究嘗試發(fā)現(xiàn)問題、探索問題、解決問題能力。（3）掌握應(yīng)用數(shù)學知識解決物理問題的能力。3．情感態(tài)度與價值觀（1）通過猜測與探究享受成功的快樂。（2）感受物理就在身邊，有將物理知識應(yīng)用于生活和生產(chǎn)實驗的意識。三、教學重點、難點在具體問題中如何根據(jù)力的實際作用效果和平行四邊形定則進行力的分解。
人教版新課標高中物理必修2向心力教案2篇
3．進一步體會力是產(chǎn)生加速度的原因，并通過牛頓第二定律來理解勻速圓周運動、變速圓周運動及一般曲線運動的各自特點。（三）、情感、態(tài)度與價值觀1．在實驗中，培養(yǎng)學生動手、探究的習慣。2．體會實驗的意義，感受成功的快樂，激發(fā)學生探究問題的熱情、樂于學習的品質(zhì)。教學重點1．體會牛頓第二定律在向心力上的應(yīng)用。2．明確向心力的意義、作用、公式及其變形，并經(jīng)行計算。教學難點1．對向心力的理解及來源的尋找。2．運用向心力、向心加速度的知識解決圓周運動問題。教學過程（一）、 引入新課：復習提問：勻速圓周運動的物體的加速度——向心加速度，它的方向和大小有何特點呢？學生回答后進一步引導：那做勻速圓周運動物體的受力有什么特點呢？是什么力使物體做圓周運動而不沿直線飛出？請同學們先閱讀教材
新人教版高中英語必修1Unit 1 Teenage Life-Reading for Writing教案
【教材分析】This teaching period mainly deals with reading for writing a letter of advice. Students are expected to learn the knowledge about how to write a suggestion letter. The teacher is expected to enable students to master some writing skills concerning suggestion letters and learn to write one.【教學目標與核心素養(yǎng)】1. Get students to have a good understanding of how to write a suggestion letter properly.2. Enable students to use some writing skills flexibly.3. Develop students’ writing and cooperating abilities.4. Strengthen students’ great interest in writing discourses.【教學重難點】1. How to enable students to have a good understanding of the skills of writing a suggestion letter2.How to enable students to write a good recommendation letter using some writing skills properly.【教學過程】Step 1: Lead in Begin the class with the lead-in questions: how to write a letter for advice? What kinds of aspects should be included? It is strongly recommended that the teacher should ask students to discuss the topic freely with their partners and brainstorm some ideas concerning the topic. In this way, students can come up with more ideas and avoid being nervous at the beginning of the class.Step 2: Read to discover details concerning advice letters’ writing style.The teacher is expected to ask students to read a letter offering some advice on page 18 silently and then request students to discuss the questions below.
人教版高中語文必修2《成語：中華文化的微縮景觀》教案2篇
七、教學反思這堂課有眼下看得見的效果和暫時看不見的長遠的效果，學生收益明顯：1．學生學到的不只是成語本身。學生從網(wǎng)絡(luò)上搜集材料，分析整理，不只是學成語，探究能力也得到提高。對成語的梳理探究，是讓學生做一件很具體的事——梳理、分析、歸類。重在過程，重在課外、課前學生的工作。這樣的教學設(shè)計很有價值，讓學生在活動中得到提高。2．開拓了學生的眼界。學生放眼各種報刊，從報刊中發(fā)現(xiàn)問題——大家都可能出錯。這樣一來學生的眼界變寬了，自信心增強了。3．對成語的理解、運用比過去深刻。讓學生從對一個個具體成語的理解入手，進而認識到以后用成語不能犯“望文生義”等錯誤，從個例上升到一般。4．讓學生知道以后自己運用成語應(yīng)抱什么態(tài)度，用什么方法。別人錯用成語，是前車之鑒。
人教版新課標高中物理必修2生活中的圓周運動教案2篇
思考：洗衣機脫水時轉(zhuǎn)速高時容易甩干衣物，還是轉(zhuǎn)速低時容易甩干衣物？(2) 制作棉花糖的原理內(nèi)筒與洗衣機的脫水筒相似，里面加入白砂糖，加熱使糖熔化成糖汁。內(nèi)筒高速旋轉(zhuǎn)，黏稠的糖汁就做離心運動，從內(nèi)筒壁的小孔飛散出去，成為絲狀到達溫度較低的外筒，并迅速冷卻凝固，變得纖細雪白，像一團團棉花。5.離心現(xiàn)象的防止在水平公路上行駛的汽車，轉(zhuǎn)彎時所需的向心力是由車輪與路面的靜摩擦力提供的。如果轉(zhuǎn)彎時速度過大，所需向心力F大于最大靜摩擦力Fmax，汽車將做離心運動而造成交通事故。因此，在公路彎道處，車輛行駛不允許超過規(guī)定的速度。當高速轉(zhuǎn)動的砂輪或者飛輪內(nèi)部分子間相互作用力不足以提供所需向心力時，離心運動就會使他們破裂，甚至釀成事故。
