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2、椀琀攀栀椀洀愀氀攀琀琀攀爀圀愀渀琀猀戀琀漀搀漀猀琀栀婎譧匀琀愀礀愀琀夀销x瀀稅踁,圀胔-鈀怀0i縀$能量的转化与守恒课件(人教版九年级).ppt16a197fdc4aa4806b8f534f4059b864d.gif能量的转化与守恒课件(人教版九年级).ppt2020-91fdb0f5e4-d000-4f3c-897d-ac08d70b264434be+4+ACwvrSG4iBbR9PQkx1jLJuEuPJjSQAXTyG9jHpsvxhQ3ziw=能量,转化,守恒,课件,人教版,九年级E:wenkuwebuiFlexPaperFileRoot17668b9bfe6f62a0c2dac360
3、aa840ae6能量的转化与守恒 学习目标 1知道能量守恒定律 2能举出日常生活中能量守恒的 实例 3能用能量守恒的观点分析物理 现象 学前指导 学生自学:看P142-144页的 内容, 并回答下面的问题。 1、自然界中的各种现象都是互相联系的 ,可以从能量的角度反映这种联系做142页的 “想想做做”,观察实验所发生的现象,发生了 哪些能量转化? 实验1:现象_, 能转化为_ _; 实验2:现象_, 能转化为_ _; 实验3:现象_, 能转化为_ _; 实验4:现象_, 能转化为_ _ 2、 通过上述“想想做做”,我们发现 在一定条件下,各种形式的能都可以相互转化 : 摩擦生热: 能转化为 能
4、; 水电站里水轮机带动发电机发电: 能转化为 能; 电动机带动水泵把水送到高处: 能转化为 能; 植物吸收太阳光进行光合作用: 能转化为 能; 燃料燃烧时发热: 能转化为 能 3、综上所述,各种形式的能量都可 以在一定条件下相互转化,图16.5-1给 出了两个实例,能做些补充吗? 内能to光能: 物体高温下发光 内能to机械能: 热机 内能to电能: 热电站 内能to化学能: Ba(OH)2+NH4Cl的反应(吸热) 电能to内能: 电热毯 电能to光能: 电灯泡 电能to机械能: 电动机 电能to化学能: 给电池充电 化学能to内能: 木炭燃烧 化学能to光能: 萤火虫 化学能to机械能:热
5、机做功冲程 化学能to电能: 电池对外供电 光能to内能:晒太阳 光能to机械能:太阳帆(光照产生压强) 光能to电能:太阳能电池板 光能to化学能:光合作用 机械能to内能:摩擦生热 机械能to光能:(空) 机械能to电能:发电机 机械能to化学能:在一个存在二氧化硫、三氧化 硫和氧气的密闭容器中,用外力压缩容器,化学 平衡向生成二氧化硫和氧气的方向移动。机械能 转化为二氧化硫和氧气的化学能 4、阅读143页“想想议议”,分析现 象产生的原因,回答下列问题: 为什么它们的高度会逐渐降低? 是否丢失了能量? 减少的机械能到哪里去了? 5、科学工作者经过长时间的探索,发现自 然界的各种现象不是孤
6、立的,而是互相联系的看 书143页,熟记能量守恒定律的内容,完成下列填 空: 能量守恒定律:能量既不会凭空 ,也不会 凭空 ,它只会从 转化为 ,或者从一个物体 另一个物体,而在转化 和转移过程中,能量的总量 意义:能量守恒定律是自然界最 、最 的基本定律之一 检测练习 看145页第二题:分析永动机能否实现 无法实现的“永动机“ 1.“永动机“:不消耗任何能量和燃料,却源 源不断对外做功的机器。 2.由能量守恒定律知:无法实现 3.工程技术的任务,在于设法找出合理利用 能源的途径,并减少机器运转过程中不 必要的能量损耗,而不是去研制永远无 法实现的“永动机”。 学习目标回顾 3能说出功的原理,
7、知道使用任 何机械都不省功。 当堂检测 1下列关于能量转化的实例,你认 为说法正确的是( ) 水轮机带动发电机发电电能转 化为机械能 燃料燃烧化学能转化为内能 汽油机的做功冲程机械能转化 为内能 给蓄电池充电化学能转化为电 能 2下列关于杠杆或能量守恒的说法中,正 确的是( ) 在使用杠杆的过程中,不可能既省力又 省距离 天平是等臂杠杆,既省力又省距离 由能量守恒定律可知,永动机总是可以 制造成功的 由能量守恒定律可知,滑轮组的机械效 率可以超过100 3以下交通工具中,所使用的动力装置将 电能转化为机械能的是( ) 摩托车 载重卡车 拖拉机 电动自行车 4火箭发射升空时,燃料通过燃烧将 _能
8、转化为燃气的内能,燃气对火 箭做功,又将内能转化为火箭的 _能 8如图所示,将一物体分别沿着光滑 斜面AO和BO匀速拉到顶端O点,已知 AOW2 CF1F2,W1W2 DF1F2,W1W2 教育咨询0000200006中学资料20200901214555781121weM0a5hgyX/zMbqN2xawpjsPJ9IlaaWVtT8OPhqk2s/SvV3gktq9II6sV0HI9DPg能量的转化与守恒 学习目标 1知道能量守恒定律 2能举出日常生活中能量守恒的 实例 3能用能量守恒的观点分析物理 现象 学前指导 学生自学:看P142-144页的 内容, 并回答下面的问题。 1、自然界中的
9、各种现象都是互相联系的 ,可以从能量的角度反映这种联系做142页的 “想想做做”,观察实验所发生的现象,发生了 哪些能量转化? 实验1:现象_NUnit 3 Period 1 Now we are at the gate of the zoo. We cant see any animals, but we can hear some of them. What animals can we hear? Listen and guess. 倾听动物倾听动物 Listen to the animals.Listen to the animals. koalakua:l lion lain tig
10、er taig Elephant elifnt dolphin d lfin panda pnd giraffe d3ira:f penguin pegwin Lets Lets guess!guess! - Is it a ? -Yes, it is./ No, it isnt. Its a giraffe. 走近动物走近动物. . Get close to the animals.Get close to the animals. - Is it a ? -Yes, it is./ No, it isnt. Its an elephant. 走近动物走近动物. . Get close to
11、 the animals.Get close to the animals. .Match: lion dolphin penguin giraffe koala elephant panda tiger h d a e f g c 1b Listen and check the animals you hear: Conversation 1 Girl: Lets see the pandas first. Pandas are my favorite animals. Boy: Why is that? Girl: Because theyre very cute. Conversatio
12、n 2 Boy: Lets see the giraffes. Girl: Why? Boy: Because theyre interesting. Conversation 3 Girl: Lets see the penguins now. I like penguins. Boy: Why? Girl: Because theyre beautiful. scary ugly small cute friendly koalakoala .Know the animals: kua:l n.树袋熊,考拉 koalakoalas s cute adj. 可爱的 interesting s
13、mall tigertiger .Know the animals: taig n.老虎 tigertigers s scary big elephantelephant .Know the animals: elifntn.大象 elephantelephants s friendly adj. 友好的 anan elephant elephant be friendly to sb.对某人友好 friendly n. friend dolphindolphin .Know the animals: d lfinn.海豚 dolphindolphins s C smart adj. 敏捷的
14、clever adj. 聪明的 pandapanda pandapandas s .Know the animals: pndn.熊猫 beautiful adj.美丽的 shy adj. 害羞的 giraffegiraffe .Know the animals: d3ira:f n.长颈鹿 giraffegiraffes s beautiful tall penguinpenguin .Know the animals: pegwin n.企鹅 penguinpenguins s fun friendly lionlion .Know the animals: lain n.狮子 lionl
15、ions s ugly adj. 丑陋的 scary interesting fun smart cute A: Lets see the lions. B: Why do you want to see the lions? A: Because theyre cute. Practise the dialogue with these words: interesting . Presentation A: Lets see the koalas first. B: Why do you want to see the koalas? A: Because theyre . cute in
16、teresting cute interesting and cute scary . Presentation A: Lets see the first. B: do you want to see the ? A: theyre . tigers Whytigers Becausescary big big big and scary . Presentation A: Lets see the first. B: do you want to see the ? A: theyre . friendly clever smart elephants Why Because elepha
17、nts friendly dolphins dolphins cleversmartclever and smart A: Lets see the first. B: do you want to see the ? A: theyre . beautiful and shy ugly and scary fun and friendly tall and beautiful . Practice koalas dolphins 2b Listening 2b Listen and complete the conversation with the words in the box . v
18、ery dolphins kind of koalas Julia: Lets see the koalas . Henry : Why do you like _? Julia: Because theyre _ cute. Henry : Well, I like _. Julia: Why do you like ? Henry: Because theyre interesting. koalas very dolphins dolphins kind of .Difficult very + adj. / adv. kind of + adj./ adv. very cute sca
19、ry friendly clever shy fun interesting smart ugly beautiful kind of cute shy ugly friendly fun beautiful scary clever smart interesting very adv. 很,非常 kind of 有几分 kind of = a little A: What animals do you like ? B: I like A: Why do you like? B: Because theyre very /kind of /cute /smart /interesting.
20、 lion dolphin penguin giraffe koalas elephant tiger panda 2cPair work Lucy Tom . Make a conversation. What animals do you like? Why do you like pandas? Where are pandas from? I like pandas. Because they are kind of cute. They are from China. lions / South Africa koalas / Australia . Make a conversat
21、ion. south adj.南方的; n.南方 Africa 非洲 I like koalas. Because they are kind of cute . They are from Australia. B: B: B: A: A: A: What animals do you like? Why do you like koalas? Where are koalas from? I like lions. Because they are very scary . They are from South Africa. Why do you like lions? Where a
22、re lions from? Where are they from? Pandas are from Sichuan, China. Koalas are from Australia(澳大利亚) Tigers are from Asia, like China. Elephants are from Africa(非洲). Lions are from Africa. Giraffes are from Africa. Penguins are from South Pole. Dolphins are from the sea. Bingo . Game lion dolphin pen
23、guin giraffe koala elephant tiger panda dog tiger panda elephantlion koala penguin dolphin giraffe dog Animal Marias words Tonys words elephant s pandas Fill in the chart: interesting clever ugly beautiful shy cute interesting clever ugly cute beautiful shy Tony: Where do you want to go now? Maria:
24、Lets see the elephants. Tony: The elephants? Why do you like elephants? Maria: Oh, theyre interesting. And theyre really clever. Tony: Yes, but theyre ugly, too. Maria: Oh, Tony! So, where do you want to go? Tony: Lets see the pandas. Theyre kind of cute. Maria: Oh, yeah. I love pandas. Theyre beaut
25、iful. But theyre also kind of shy. Where are they? Tony: Theyre over there on the left, just across from the koalas. other A:What animals do you like? B: I like elephants. They are cute. A: What other animals do you like? B: I like dogs,too. A: Why? B: Because theyre friendly and clever. A:What anim
26、als do you like? B: I like .s They are . A: What other animals do you like? B: I like s,too. A: Why? B: Because theyre Molly? Ling Ling? Bill ? 3a:(p17) This is Larry. Hes from _. Hes eight _ old.He _ meat. Larry is _. He usually _and relaxes 20 hours every day ! Africa years this eats sleeps lazy A
27、frica years eats lazy sleeps 3b: Where are they from? Pandas are from Sichuan, China. Koalas are from Australia(澳大利亚) Tigers are from Asia, like China. Elephants are from Africa(非洲). Lions are from Africa. Giraffes are from Africa. Penguins are from South Pole. Dolphins are from the sea. What food d
28、o they like? Pandas like bamboos. Koalas like leaves(树叶) Tigers like meat. Elephants like grass. Lions like meat. Giraffes like leaves. Penguins like seafood. Dolphins like fish. . Exercise 1 1. 1. T T are the most dangerousare the most dangerous(危险的)(危险的) animals , I think.animals , I think. 2. 2.
29、P P_ are the animals that only live in China._ are the animals that only live in China. 3. I think3. I think a large a large grass-eating animal which has a long neck animal which has a long neck(长脖子)(长脖子) is the is the g g _._. 4. The 4. The d d _ is one of _ is one of the cleverest animals, living
30、 in the cleverest animals, living in the sea sea( 海洋)海洋) and looking like a fish.and looking like a fish. 5. Why do you like 5. Why do you like k k _? Because theyre fun._? Because theyre fun. 6. The biggest 6. The biggest animals on land on land(在陆地上)(在陆地上) are are e e _._. 7. 7. P P_ live in very cold_ live in very cold(冷)(冷) places.places