書法藝術(shù)的繁榮期,是從東漢開始的東漢時(shí)期出現(xiàn)了專門的書法理論著作,最早的書法理論提出者是東西漢之交的揚(yáng)雄第一部書法理論專著是東漢時(shí)期崔瑗的《草書勢》漢代書法家可分為兩類:一類是漢隸書家,以蔡邕為代表一類是草書家,以杜度、崔瑗、張芝為代表,張芝被后人稱之為“草圣”最能代表漢代書法特色的,莫過於是碑刻和簡牘上的書法東漢碑刻林立,這一時(shí)期的碑刻,以漢隸刻之,字型方正,法度謹(jǐn)嚴(yán)、波磔分明此時(shí)隸書已登峰造極漢代創(chuàng)興草書,草書的誕生,在書法藝術(shù)的發(fā)展史上有著重大意義它標(biāo)志著書法開始成為一種能夠高度自由的抒發(fā)情感,表現(xiàn)書法家個(gè)性的藝術(shù)草書的最初階段是草隸,到了東漢時(shí)期,草隸進(jìn)一步發(fā)展,形成了章草,后由張芝創(chuàng)立了今草,即草書
最后,公司要城信經(jīng)營,樹立良好的信譽(yù)與企業(yè)形象。教師活動(dòng):引導(dǎo)學(xué)生閱讀教材P44“金華火腿”的事例;多媒體播放電視系列片3:“小天鵝”重視產(chǎn)品質(zhì)量的例子,國家對洗衣機(jī)的質(zhì)量標(biāo)準(zhǔn)是4000次運(yùn)行無故障,而國際標(biāo)準(zhǔn)是5000次,為此,廠里組織近百名科技人員,花了兩年時(shí)間進(jìn)行全廠性技術(shù)攻關(guān),終于實(shí)現(xiàn)了無故障運(yùn)行5000次?!靶√禊Z”以它的信譽(yù)和質(zhì)量給企業(yè)帶來了巨大效益,1000多人的廠子,年銷售收入10.03億元,實(shí)現(xiàn)利潤1.72億元,公司躋身于全國500家大型企業(yè)的行列,企業(yè)綜合經(jīng)濟(jì)效益居全國18位。設(shè)問:兩個(gè)企業(yè)不同命運(yùn)的原因何在?學(xué)生活動(dòng):思考討論,發(fā)表見解。教師點(diǎn)評:企業(yè)的信譽(yù)和形象對企業(yè)的生存競爭至關(guān)重要,是企業(yè)的無形資產(chǎn),是公司經(jīng)營成敗的重要因素。企業(yè)的信譽(yù)和形象集中體現(xiàn)在產(chǎn)品和服務(wù)的質(zhì)量上。創(chuàng)立名牌產(chǎn)品,實(shí)行優(yōu)質(zhì)服務(wù),是企業(yè)信譽(yù)和形象的表現(xiàn),也是企業(yè)開展正當(dāng)競爭的主要手段。
①從政府人員組成看,南京政府是一個(gè)以資產(chǎn)階級(jí)革命派為主體的政府。②從政府頒發(fā)的法令和措施看,這些法令體現(xiàn)了資產(chǎn)階級(jí)民主革命的要求,對于發(fā)展民族資本主義經(jīng)濟(jì)、資產(chǎn)階級(jí)民主政治和文化教育以及改革社會(huì)風(fēng)氣,都起了積極作用。③從頒布的《中華民國臨時(shí)約法》看,憲法體現(xiàn)了三權(quán)分立的政治體制,體現(xiàn)了資產(chǎn)階級(jí)民主主義的要求,是中國歷史上第一部資產(chǎn)階級(jí)民主憲法,具有反封建專制制度的進(jìn)步意義。(2)從南京臨時(shí)政府的內(nèi)外政策分析南京政府的根本弱點(diǎn)①未徹底地反封建。它沒有采取比較徹底的反對封建主義的措施,特別是對封建統(tǒng)治的基礎(chǔ)——地主階級(jí)土地所有制沒有觸動(dòng),這樣,南京臨時(shí)政府也就不能真正地把廣大人民群眾動(dòng)員起來,因而缺乏真正的群眾基礎(chǔ)。
【備課資料】百團(tuán)大戰(zhàn)八路軍從8月20日起,在華北敵后出動(dòng)105個(gè)團(tuán),約40萬兵力,在2500公里長的戰(zhàn)線上,發(fā)動(dòng)了規(guī)模最大的“以徹底破壞正太路若干要隘,消滅部分?jǐn)橙私財(cái)嘣摼€交通”為目的的舉世聞名的“百團(tuán)大戰(zhàn)”。八路軍提出“不留一根鐵軌、不留一根枕木、不留一個(gè)車站、不留一個(gè)碉堡、不留一座橋梁”的口號(hào),“讓敵人用腳同我們賽跑”,“讓敵人用牛驢搬炮彈、飛機(jī)大炮”。八路軍展開攻堅(jiān)戰(zhàn),端掉敵一系列據(jù)點(diǎn)。據(jù)有關(guān)資料記載,從8月20日到12月5日,在歷時(shí)三個(gè)半月的“百四大戰(zhàn)”中,我軍共進(jìn)行大小戰(zhàn)斗1824次,斃傷日偽軍25800余人,俘日偽軍18600余人,繳獲了大批武器、彈藥和軍用食品等;破壞鐵路470多公里,公路1500多公里,橋梁、車站、隧道等260余處,使正太鐵路停運(yùn)月余;攻克日偽據(jù)點(diǎn)2993個(gè),鞏固和擴(kuò)大了抗日軍民占領(lǐng)區(qū)。
【合作探究】分析說明巴黎公社是無產(chǎn)階級(jí)建立政權(quán)的第一次偉大嘗試(1)從巴黎公社產(chǎn)生的情況來看,它是在巴黎無產(chǎn)階級(jí)通過暴力革命,推翻反動(dòng)的資產(chǎn)階級(jí)政府的基礎(chǔ)上,通過普選建立起的新型國家。(2)從巴黎公社的政權(quán)的領(lǐng)導(dǎo)人和階級(jí)成分來看,通過民主選舉產(chǎn)生的公社委員會(huì)的成員,大多數(shù)是工人,其中有些委員會(huì)雖然從事不同的職業(yè),有的不是馬克思主義者,但公認(rèn)是公認(rèn)階級(jí)的代表。(3)從巴黎公社實(shí)行的政策措施來看,這是最能說明公社性質(zhì)的一個(gè)方面。公社在建設(shè)新政權(quán)的同時(shí),打碎資產(chǎn)階級(jí)國家機(jī)器,做出建立無產(chǎn)階級(jí)專政國家機(jī)器的偉大嘗試。公社的社會(huì)經(jīng)濟(jì)措施和其他民主措施,都在一定程度上體現(xiàn)了它的無產(chǎn)階級(jí)性質(zhì)。沒收逃亡資本家的工廠,觸及資本主義私有制,具有明顯的無產(chǎn)階級(jí)性質(zhì)。
教師活動(dòng):針對學(xué)生的辯論作點(diǎn)評、總結(jié):(4)勤儉節(jié)約、艱苦奮斗勤儉節(jié)約、艱苦奮斗是我國的傳統(tǒng)美德,是一種民族精神,而不是一種具體的消費(fèi)行為。作為精神,它是永遠(yuǎn)不過時(shí)的。特別是我國還處在社會(huì)主義的初級(jí)階段,生產(chǎn)力水平還比較低,還面臨人口、資源等壓力,我們更應(yīng)該發(fā)揚(yáng)勤儉節(jié)約、艱苦奮斗的優(yōu)良作風(fēng)。從個(gè)人思想品德的修養(yǎng)角度講,有利于個(gè)人優(yōu)秀品德的形成和情操的陶冶,是有志者應(yīng)該具備的精神狀態(tài)。當(dāng)然,不能把勤儉節(jié)約、艱苦奮斗與合理消費(fèi)對立起來,勤儉節(jié)約不是抑制消費(fèi)而是說不要浪費(fèi)??傊?,以上四個(gè)原則,是科學(xué)消費(fèi)觀的具體要求,我們要理解和掌握這些原則,并用他們指導(dǎo)自己的消費(fèi)行為,既有益于個(gè)人,也有益于社會(huì),將促進(jìn)個(gè)人的健康發(fā)展和社會(huì)的可持續(xù)發(fā)展。
Good expressions that students can choose to use: help the travelers choose which tour to take1. In my opinion, you could/might choose…, because you prefer to…2. …could be a perfect choice for you, for…3. As far as I am concerned, you would enjoy…, for…4. …would probably suit you, because you enjoy/love/hate doing…Step 5 Passage ConsolidationLanguage appreciation:1. You can then spend three days exploring the rainforest with a local guide and enjoying the plants and animals unique to the rainforest. 在接下來的三天里,您可以在當(dāng)?shù)貙?dǎo)游的陪同下,深入雨林進(jìn)行探索,欣賞雨林特有的動(dòng)植物。本句主體結(jié)構(gòu)為spend some time doing sth. 2. Inca builders cut stones to exact sizes so that nothing was needed to hold walls together other than the perfect fit of the stones. 印加的建筑工人將石頭切割成精確的尺寸,僅僅憑著石頭間的完美契合,即可穩(wěn)固墻體。本句為so that引導(dǎo)的結(jié)果狀語從句。nothing與the perfect fit為并列成分; other than在句中意為“除了”。Step 6 HomeworkSuppose you will travel to Peru, write a short essay about your three-day tour plan.
2. Sort out detailed information about Michael Jordan.(1) Understand the transitional sentence.Q: Which part is about Michael Jordan as a master? Which part is about the example he set?(2) Have the Ss Focus on why Michael Jordan is a master and what good examples Michael Jordan set when they’re reading. And think about these questions as below:Q1: How does the author describe his impressive skills?Q2: How do you understand “time seemed to stand still”?Q3: What does “graceful” mean?Q4. Which sentence do you think best describes his mental strength?Q5. Which words is important in the sentence in describing his mental strength? Why?Q6: How do you understand “unique”?Q7: What can we learn from Michael Jordan?Step 5 Discussing and recommendingRecommend their own living legends of sports.Work in groups to choose your own living legend of sports and give the reasons of your choice. Step 6 HomeworkReview the stories of Lang Ping and Michael Jordan, and try to retell them.
【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(xué)目標(biāo)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(xué)重難點(diǎn)】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(xué)過程】Step1: 語法知識(shí)呈現(xiàn)定語從句(一)—關(guān)系代詞的用法在復(fù)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(dǎo),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(dǎo)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(dāng)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。
5. Read to get detailed information about Paragraph 5.Q1. What shows the revival of Tangshan?Q2. How can Tangshan revive itself and get up on its feet again?Q3. In times of disasters, how can we go through it?T: In times of disasters, we should unify, show the wisdom and stay positive.Step 4 Activity 4 Highlighting the theme and reflecting1. Make a summary of the text.2. Further understand the titleQ: After our learning, why do you think the earth didn’t sleep on that night?T: An earthquake happened. The people in the earthquake suffered a lot, and the people outside Tangshan were concerned about the people there a lot.3. Reflect through discussion on what can be learnt after reading.T: Disasters are powerful. Unpreparedness can be deadly. Life is weak, but if people work together to help each other, disasters can be defeated.There is no love from disaster, but we have love in the human heart.Step 5 Assignment How does the writer convey that the earthquake was deadly, and that people were helpless during the earthquake? Try to find some attractive and impressive expressions and note them down.
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(xué)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(xué)生會(huì)(the Students‘ Union)的名義寫一份海報(bào),歡迎全校同學(xué)參加,屆時(shí)特邀本校美籍教師史密斯先生頒獎(jiǎng)。? 報(bào)名時(shí)間 9月30日以前(報(bào)名:signup)? 報(bào)名地點(diǎn) 學(xué)生會(huì)辦公室? 比賽時(shí)間 10月9日晚7:00~9:00? 比賽地點(diǎn) 學(xué)校大會(huì)議室? 獎(jiǎng)勵(lì) 前8名
This theme of the part is “ Describe people or things in greater detail”. Students have learned the grammar(restrictive relative clauses) in Book 1, and further review and consolidate its structure “prep+relative pronouns(which/whom)” and the relative adverbs(when, where and why), besides students should understand its form, meaning and functions. In this section, students should be able to express the grammar correctly in daily communication and in the writing. 1. Review the basic usages of relative pronouns and adverbs of attributive clauses . 2. Learn to use some special cases about restrictive relative clauses.3. Learn to write sentences with restrictive relative clauses flexibly according to the context.1. Review the basic usages of relative pronouns and adverbs of attributive clauses .2. Learn to use some special cases about restrictive relative clauses.3. Learn tow rite sentences with restrictive relative clauses flexibly according to the context.Step 1. Observe the following sentences, and mark the relative pronouns and the adverbs. 1. After listening to the scientists who had studied the problems, and citizens who lived near the dam, the government turned to the United Nations for help.2. Temples and other cultural sites were taken down piece by piece, and then moved and put back together again in a place where they were safe from the water.Step 2 PracticePlease complete these sentences with relative pronouns and relative adverbs and answer the following questions.Questions: 1. What is the head noun ?2. What relative words should be used ?3. What elements do they act in these sentences ?
The theme of the reading and thinking is about “Understanding how a problem was solved”.The Listening & Speaking & Talking is about international co-work to protect the Mount Tai, in which the students from seven countries came up with many solutions even create the Mount Tai App. This section aims at showing how to solve a difficult and even tough problem about protecting the cultural heritage by the international co-work. So in this section, cultivating students’ international awareness is very clear and important. Concretely, with the economic development, how to balance the protection of cultural relics and social development is a big challenge for human. In the 1950s, the Egyptian government wanted to build the Aswan Dam across the Nile to control floods, produce electricity and water farms. But the proposal led to protests because it would destroy a lot of cultural relics. The Egyptian had no choice but ask the UN for help. Therefore, a international cooperation about how to protect the cultural relics began, which involved the time length about 20 years and a large amount of fund. Then, the problems was solved. 1. Read quickly to get the main idea and the structure of the article; read careful to get detailed information.2. Learn to use the reading strategy---making a timeline3. Learn how to solve a tough problem by asking for help and cooperation4. Have the international awareness and understand the great strength of international cooperation.1. Read quickly to get the main idea and the structure of the article; read careful to get detailed information.2. Learn to use the reading strategy---making a timeline.3. Learn how to solve a tough problem by asking for help and cooperation.
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是對文本內(nèi)容和詞匯學(xué)習(xí)成效的檢測。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。
本活動(dòng)旨在落實(shí)課時(shí)教學(xué)目標(biāo)2。 1.Think, discuss and share. Students form groups of 4, discuss about the given ending make comments. Q1: Do you like the ending? Q2: Was it a logical ending? Why so or why not? [設(shè)計(jì)意圖]通過引導(dǎo)學(xué)生思考、討論、評價(jià),比較個(gè)人、同伴所預(yù)測的結(jié)局和聽力文本所給定的結(jié)局的異同點(diǎn),深化對文本的認(rèn)知,發(fā)展學(xué)生的評判性思維能力。 Activity 4: Exploring Asimov’s three laws of robotics and the purpose of the writing 本活動(dòng)旨在落實(shí)課時(shí)教學(xué)目標(biāo)3。 1. Get to know Isaac Asimov’s three laws of robotics. The teacher shares Isaac Asimov’s three laws of robotics. The three laws state that: ①A robot may not injure a human being or, through inaction, allow a human being to come to harm. ②A robot must obey any orders given to it by human beings, except where such orders would conflict with the First Law. ③A robot must protect its own existence as long as such protection does not conflict with the First or Second Law. Q: How does Tony’s story relate to the laws? 2. Figure out Isaac Asimov’s purpose of writing Satisfaction Guaranteed. The students express their opinions about the author’s writing purpose. Q: Why did Isaac Asimov write such a story? S: To explore the relationship between robots and humans. [設(shè)計(jì)意圖]通過了解艾薩克·阿西莫夫所制定的機(jī)器人三大定律,加深學(xué)生對文本的理解,深入探究文本的主題意義。推理作者的寫作目的,聯(lián)系生活實(shí)際,思考人類與機(jī)器人的關(guān)系。
科學(xué)家預(yù)測,就地區(qū)而言,位于低緯度的大部分國家,農(nóng)作物的產(chǎn)量將減少;而位于高緯度的國家,農(nóng)作物產(chǎn)量有可能增加。由于不少發(fā)展中國家位于低緯度地區(qū),因此,氣候變化的這種區(qū)域差異性,可能會(huì)使發(fā)展中國家所面臨的問題更為嚴(yán)峻。板書:3全球變暖將加劇水資源的不穩(wěn)定性與供需矛盾。介紹:全球變暖會(huì)影響整個(gè)水循環(huán)過程,可能使蒸發(fā)加大,改變區(qū)域降水量和降水分布格局,增加降水極端異常事件的發(fā)生,導(dǎo)致洪澇、干旱災(zāi)害的頻次和強(qiáng)度增加,以及地表徑流發(fā)生變化。隨著徑流減少,蒸發(fā)增強(qiáng),全球變暖將加劇水資源的不穩(wěn)定性與供需矛盾。轉(zhuǎn)折:既然全球變暖會(huì)引起很多不利影響,那么作為人類應(yīng)如何面對這一挑戰(zhàn)呢?這就是我們要討論的第三個(gè)問題。板書:三、氣候變化的適應(yīng)對策討論:請大家閱讀結(jié)合教材P53氣候變化的適應(yīng)對策部分討論人類應(yīng)如何面對全球變暖這一問題 呢?
當(dāng)時(shí),不只發(fā)生了太陽風(fēng)暴,同時(shí)還有其它的現(xiàn)象發(fā)生,導(dǎo)致災(zāi)難巨大。 如果,這些現(xiàn)象單獨(dú)地發(fā)生,結(jié)果就會(huì)是另外一個(gè)樣子。正是由于這些因素綜合起來,1859年的太陽風(fēng)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(gè)被“擊中”日本航天機(jī)構(gòu)29日聲明,受強(qiáng)烈的太陽磁暴影響,28日晚,日本“兒玉(Kodama)”通訊衛(wèi)星信號(hào)中斷。 據(jù)美聯(lián)社報(bào)道,在太陽黑子活動(dòng)減弱后,“兒玉”通訊衛(wèi)星恢復(fù)正常運(yùn)轉(zhuǎn)。 美歐研究人員28日發(fā)布新聞公告稱,太陽當(dāng)天發(fā)生了一次強(qiáng)烈的耀斑爆發(fā),預(yù)示著新一輪太陽風(fēng)暴將在今后一兩天內(nèi)抵達(dá)地球,地球上的通信等設(shè)施可能會(huì)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(qiáng)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(shí)750萬公里的速度奔地球而來,其與地球磁場作用后可能會(huì)形成比較強(qiáng)烈的地磁暴,使地球兩極出現(xiàn)極光,并可能對衛(wèi)星運(yùn)行和通信等造成干擾。
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(diǎn).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(shí)盲點(diǎn)―我國航天事業(yè)接近并超過發(fā)達(dá)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(jìn)熱點(diǎn)主要是要學(xué)生明白:宇宙環(huán)境保護(hù)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(shí)點(diǎn)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(shí)點(diǎn)使學(xué)生對知識(shí)有整體掌握.使學(xué)生能堅(jiān)持用科學(xué)的觀點(diǎn)分析發(fā)現(xiàn)各種新問題.(四)布置作業(yè)用發(fā)展的觀點(diǎn)談?wù)剬χ袊訌?qiáng)航天事業(yè)發(fā)展的看法.鞏固所學(xué)知識(shí):聯(lián)系實(shí)際為下節(jié)課學(xué)習(xí)做鋪墊.板書設(shè)計(jì)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(hù)
一、 天體1、 概念:宇宙間物質(zhì)的存在形式。(聚集態(tài)的星體及星際物質(zhì))注:不作特殊交代的天體均指自然天體2、 幾種常見天體的觀察(指導(dǎo)學(xué)生閱讀課本,并總結(jié)講述學(xué)生自己平時(shí)的生活所見)3、幾種常見的天體恒星1) 定義:從質(zhì)量、組成、形狀、發(fā)光與否等角度總結(jié)交代:數(shù)目多少(肉眼所見6000多顆)夜空里的點(diǎn)點(diǎn)繁星差不多都是恒星2)運(yùn)動(dòng)特點(diǎn):(由恒星的“恒”字引發(fā)學(xué)生分析“北斗七星圖形變化”圖說明特點(diǎn))結(jié)論:①恒星在不停的運(yùn)動(dòng)變化之中②相對位置似乎固定不變,故稱“恒星”3)光年----計(jì)量天體距離的單位(強(qiáng)調(diào)“距離”)分析知識(shí)點(diǎn):①距離地球最近的恒星是 (8分鐘)(1. 5億公里)②距離地球次運(yùn)的恒星是 (4.2光年)③現(xiàn)在能夠探測到的最遠(yuǎn)天體距離地球多遠(yuǎn)?星云(指導(dǎo)學(xué)生閱讀課本與恒星比較總結(jié)星云特點(diǎn),可以從形態(tài)、質(zhì)量、體積、密度、物質(zhì)組成、觀察特點(diǎn)幾方面列表比較分析并小結(jié))二、天體系統(tǒng)1、 概念:運(yùn)動(dòng)著的天體與天體之間相互吸引、相互繞轉(zhuǎn)而形成的不同級(jí)別的系統(tǒng)。
一般情況下,凡是支持物對物體的支持力,都是支持物因發(fā)生形變而對物體產(chǎn)生彈力。所以支持力的方向總是垂直于支持面而指向被支持的物體。例1:放在水平桌面上的書書由于重力的作用而壓迫桌面,使書和桌面同時(shí)發(fā)生微小形變,要恢復(fù)原狀,對桌面產(chǎn)生垂直于桌面向下的彈力f1,這就是書對桌面的壓力;桌面由于發(fā)生微小的形變,對書產(chǎn)生垂直于書面向上的彈力f2,這就是桌面對書的支持力。學(xué)生分析:靜止地放在傾斜木板上的書,書對木板的壓力和木板對書的支持力。并畫出力的示意圖。結(jié)論:壓力、支持力都是彈力。壓力的方向總是垂直于支持面而指向被壓的物體,支持力的方向總是垂直于支持面而指向被支持的物體。引導(dǎo)學(xué)生分析靜止時(shí),懸繩對重物的拉力及方向。引導(dǎo)得出:懸掛物由于重力的作用而拉緊懸繩,使重物、懸繩同時(shí)發(fā)生微小的形變。重物由于發(fā)生微小的形變,對懸繩產(chǎn)生豎直向下的彈力f1,這是物對繩的拉力;懸繩由于發(fā)生微小形變,對物產(chǎn)生豎直向上的彈力f2,這就是繩對物體的拉力。