探索三角形全等的条件第一课时.doc

初中数学学科教学设计模板学校：光华学校 教材版本：北师大版 教师宋鹏武年级七年级科目数学授课时间课题3.3 探索三角形全等的条件课时安排3第 1 课时授课类型新课一、学情分析初中阶段的学生，好奇心比较强，好表现，但是自主学习能力欠缺，在教学过程中，教师应抓住学生的这些心理，有目的的抛出学生感兴趣且与课堂内容有关的问题，把学生的注意力吸引到课堂中，把主动权交给学生，让学生体会到自己是学习的主人。二、教材分析探索三角形全等的条件，这节课选自北师大版数学七年级下第三章第三节第一课时。全等三角形是平面几何的基础性的核心内容，三角形全等套件的探究是个重要的课题，是平面几何中对封闭的两个图形关系研究的第一步，它是两个三角形之间最简单、最常见的关系。教学中，不仅要关注三角形全等条件的结论，还要重视结论探究的过程以及数学思想方法的渗透。因此，本节课的知识具有承上启下的作用。三、教学目标设计知识与技能经历探索三角形全等条件的过程，掌握三角形全等的“边边边”条件并初步学会运用；同时，了解三角形的稳定性及其应用。过程与方法在探索三角形全等条件的过程中，让学生体验分类的思想有条理地思考、分析、表达、解决问题的能力，逐步培养学生推理意识和能力。情感态度与价值鼓励学生敢于实践，勇于发现，大胆探索，合作创新的精神；体会数学在生活中的作用，增强学习数学的兴趣。四、教学重点难点教学重点掌握三角形全等的“边边边”条件并初步学会运用。教学难点对三角形全等条件的分析和探索。五、教学方法探索式教学、启导式教学六、教学准备教师准备多媒体课件，用于展示的几种符合条件的全等和非全等三角形。学生准备剪刀、彩纸、尺规。七、教学策略设计问题情景引入课题抛出问题探索、归纳实际应用八教学过程设计创设情景引入课题学生活动教师活动1、学生讨论交流，并用自己的语言表述出来。（需要条件的限制）2、学生复习回顾。1、实际生活中姓名相同的人大有人在，怎样确定班上的“李明”就是我们班上的同学呢？2、什么是全等三角形？两个三角形全等需要哪些条件？设计意图培养学生的合作交流能力以及语言表达能力。温故知新。通过生活中第一问的实例，引入课题。由第二问明确探究方向。交流互动探究新知学生活动教师活动学生根据教师提出的问题，拿出课前制作好的三角形分别与同伴进行比较，同时，同学间相互交流讨论，并用自己的语言叙述出所得的结论。结论一：只给出一个条件或两个条件时，都不能保证所得的三角形一定全等；结论二：三个内角分别相等的三角形不一定全等；结论三：三边分别相等的三角形全等。（SSS） 结论四：三角形具有稳定性。（针对三角形的稳定性，学生列举生活中的例子）活动一：只给一个条件（一条边如4厘米或一个角如30）制作三角形，大家制作出的三角形一定全等吗？活动二：给出两个条件制作三角形，所得三角形一定全等吗？1、三角形的一个内角为30，一条边为3cm；2、三角形的两个内角分别为30和50；3、三角形的两边分别为4cm和6cm。活动三：给出三个条件制作三角形，所得三角形一定全等吗？（四种可能：三条边、三个角、两边一角、两角一边。今天先讨论三条边、三个角这两种情况）1、三角形的三个内角分别为40，60，80；2、三角形的三条边分别为4cm，5cm，7cm。活动四：讨论三角形的稳定性取出课前自制长度适当的木条，用钉子把它们分别钉成三角形和四边形，并拉动它们。三角形具有稳定性。你能举生活中的应用吗？在此过程中，老师巡视，指导有困难的同学。最后，对学生的结论进行补充，从而得出结论设计意图让学生体验分类的思想，在观察、比较等活动中进行推理、交流，通过分组讨论进行合作交流，采用自主探究的方式，最后得出结论。在此过程中，激活学生思维，培养学生的合作精神和表达能力。教师分类抛出问题，将主动权交给学生，并适时的给与提示，让学生感受师生合作的好处。师生互动及时应用学生活动教师活动学生认真审题，讨论交流，并在练习本上书写出解题过程。同时，两名学生把自己的解题过程书写在黑板上。教师将过程板书后，学生将自己的书写过程与教师的对比，看看有什么不同之处，哪些地方需要改进，哪些地方比较好。例：如图，AB=CD，AC=BD，ABC和DCB是否全等？试说明理由。教师对学生的书写进行点评及补充，教师再把过程书写一遍。解：ABCDCB。理由如下：因为，在ABC和DCB中 AB=DC(已知) AC=DB(已知) BC=CB(公共边)所以ABCDCB（SSS）设计意图培养学生认真审题的习惯及推理意识和能力，提高知识的应用能力引导学生熟练掌握角形全等的“边边边”条件。逐步培养学生推理意识和能力及时反馈学生活动教师活动先让学生独立完成，教师再分析，存在疑问的地方，同学间再讨论交流，并把过程书写出来。1、如图，AB=AC，BD=CD，H是BC的中点，指出图中全等三角形，它们全等的条件什么？2、四边形ABCD中，AB=CD，AD=BC。ABC和CDA是否全等？A=C吗？说明理由。设计意图让学生面对具有挑战的问题，独立尝试解决，显现出个体的差异性。在此基础上，学生相互交流、评审，取长补短，实现有差异发展，达到共同提高。体现学生的主体地位，帮助他们在自主探索和合作交流的过程中再次巩固“边边边”梳理新知学生活动教师活动学生根据自己对这节课的理解，用语言表述出自己的收获及疑问。1、本节课你有哪些收获：2、你还有哪些疑问?设计意图通过独立思考，引导学生学会自我评价通过小结，引导学生学会反思，课后作业学生活动教师活动1、习题3.62（思考，多种做法）、如图，D、F是线段BC上的两点，AB=CE，AF=DE，要使ABFECD ，还需要条件 _。并说明理由。布置作业对于选做题，要求学生尽量想出不同方法，为下节课做好铺垫。设计意图通过学生作业，及时地了解学习效果，调整教学安排。并让学生养成课前预习的习惯。加深理解，并为下一节课的学习做好铺垫。九、板书设计 3.3.1 探索三角形全等的条件三边三角一角两边一个条件 行不通 两个条件 行不通 三个条件两角一边条件一:三边对应相等的两个三角形全等.简写成“边边边”或“SSS”十、反思师生课前做好充分准备，是上好这节课的一个关键环节，让本节课的学生活动较多，在学生活动中应关注每个学生的发展，并在适时给予排忧解难。同时注重运用态势、语言对学生进行即兴评价。但要把握好学生的活动过程存在一定的难度。Unit 5 Feeling Excited. 听句子，选择正确图片。每个句子读一遍。(5分)( )1. How do they like when they hear the news?A B C( )2. Which picture is the speaker talking about?A B C( )3. How is the movie makes people feel?A B C ( )4. What is Jane doing?A B C( )5. What are they doing?A B C. 听句子及问题，选择正确答语。每个句子及问题读一遍。(5分)( )6. A. No, it doesnt look nice. B. Thank you C. Its very expensive. ( )7. A. On the road. B. In the cinema. C. In the shop. ( )8. A. 7:50. B. 7:15. C. 7:05. ( )9. A. Beijing Opera .B. Movies. C. Both Beijing Opera and movies. ( )10. A. Because he failed the English exam. B. Because he fell off his bike and was badly hurt. C. Because he missed his mother very much. 听对话，选择正确答案。每段对话读两遍。(5分)( )11. Why does Xiao Li feel happy?A. Because he will be able to go skiing this afternoon. B. Because he will have the movie ticket. C. Because his best friend will come. ( )12. What happened to Toms brother?A. He was ill. B. He got hurt. C. He fell off his bike.( )13. What does Lucy worry about?A. Speaking in front of many people. B. Seeing the doctor. C. Becoming fatter and fatter. ( )14. What will Mary do when unhappy things happen to her?A. She will listen to soft music. B. She will do something for fun. C. She will take part in activities. ( )15. Why is Linda feeling even worse?A. Because she didnt take medicine.B. Because she didnt see the doctor. C. Because she wasnt in hospital. 听短文，选择正确答案。短文读两遍。(5分)( )16. Julia left her dog to her friend because _.A. She didnt like it any moreB. She moved to a different place C. the dog wasnt lovely any longer( )17. The dog ran away from Julias friends home _.A. after Julia went back B. before Julia went back C. when it saw Julia( )18. If anyone could help her find her dog, she would _.A. give the person a present B. say thanks to him or her C. give him or her some money( )19. Julia sold _ for her dog.A. her bikeB. her booksC. her presents( )20. The dog came back itself _ later.A. two weeksB. two daysC. two months . 单项选择。（15分）( )1. Michael has a temperature, so he isnt able to come. _A. Im sorry to hear that. B. Im disappointed. C. Good luck. D. Take it easy. ( )2. Why do you _ very happy this afternoon?Because we are going to spend the evening at Lilys house. A. tasteB. soundC. lookD. smell( )3. Do you have difficulty _ English?A. to learnB. of learningC. learningD. learn( )4. New York is one of _ in the world. A. the large citiesB. the large cityC. the largest citiesD. the largest city( )5. What _ news! Yes, all of the children were _. A. excited; excitingB. exciting; excited C. excited; excitedD.exciting; exciting( )6. Helen is 15 years old, and Joan is 15, too. So Helen is _ Joan. A. as big asB. as older asC. as old asD. so old as( )7. How will you feel when _?A. you happen bad somethingB. you will happen something badC. bad something will to youD. something bad happen to you( )8. Tom didnt go hiking with his classmates _ his illness. A. becauseB. because ofC. asD. since( )9. Mr. Li makes me _, because it is bad for my health. A. dont smokeB. not smokeC. not smokingD. not to smoke( )10. When the teacher asks him, he always _.A. keep silentB. keep silentlyC. keeps silentD. keeps silently( )11. If you are _ trouble, please call me _ 72335611.A. in; inB. at; atC. at; inD. in; at( )12. He feels lonely because he has no close friends _.A. to talkB. to talk withC. talkingD. talking with( )13. The man refused to say sorry to me, _ it was his mistakes.A. becauseB. whenC. afterD. even though( )14. Im always afraid of giving a speech in front of the class. _ You can do it well. A. Im sorry to hear that. B. Take it easy. C. You are too nervous. D. Good luck. ( )15. Mom, Ill go to my friends party, but I dont know what to wear. Could you make a _ for me? OK. Let me see. A. adviceB. senseC. suggestionD. decision(A)根据语境补全对话。Father: Mike, yesterday you told me that you will have a Chinese test today. Why are you still in bed? You should get up and get 16 for school. If you dont hurry up, youll be late. Mike: I dont 17 very well. Father: Oh, dear! Whats the matter?Mike: I dont know. I have a stomachache. Father: Really? If you are 18 , youll have to 19 the doctor. Mike: Can I have some breakfast?Father: No, you 20 eat anything until you see the doctor. Mike: Dad, I will get up now. 16. _ 17. _ 18. _ 19. _ 20. _. 完形填空。(10分)Everyone needs friends. We all like to 26 close to someone. It is nice to have a friend to talk, laugh and do things with. 27 , sometimes we need to be alone. We dont always want people 28 . But we would feel lonely if we never had a friend. No two people are 29 . Friends sometimes dont get on well. That doesnt mean 30 they no longer like each other. Most of the time they will make peace with each other，and become 31 again. Sometimes friends move away. Then we feel very 32 . We miss them very much, but we can 33 them and write to them. It could be possible that we could even see them again. And we can also 34 new friends. Theres more good news for people who have friends. They live longer than people who dont have. Why? It could be that they are 35 . Being happy helps you stay well and it could be good just knowing that someone cares about you.( )26. A. lookB. watchC. feelD. see( )27. A. HardlyB. NearlyC. SuddenlyD. Certainly( )28. A. aloneB. awayC. all overD. around( )29. A. friendlyB. kindC. just the sameD. quite different( )30. A. thatB. whetherC. howD. why( )31. A. enemiesB. strangersC. studentsD. friends( )32. A. angryB. sadC. happyD. alone( )33. A. callB. askC. tellD. talk with( )34. A. look forB. findC. makeD. know( )35. A. happierB. strongerC. kinderD. richer. 阅读理解。（30分）(A)One day, a boy had a fight with one of his classmates. He didnt wait until school was over, and hurried home to his grandfather. He told him his story angrily. “He is really bad,” the boy said, “and I hate him.”The grandfather said, “Let me tell you a story. When I was a boy, I, too, sometimes hated others for what they did”As the boy listened carefully, the grandfather went on, “There are always two tigers inside my heart. One is good and kind. He gets on well with everything around him. But the other is bad and unfriendly. Even the smallest thing will make him angry. He fights with everyone all the time, and for no reason. He cant think carefully because he always hates others. It is difficult to live with these two tigers inside my heart. They both try to control me.”The boy looked into his grandfathers eyes and asked, “Which tiger always controls you, Grandfather?”The old man said slowly and seriously, “The one that I feed. I always feed the good and kind tiger, so I never hate others and seldom get angry now.”根据短文内容，选择最佳答案。( )36. The boy went to his grandfather _.A. before he went to schoolB. when he went to schoolC. after school was overD. after he had a fight( )37. The good tiger _ everything around him.A.doesnt likeB. gets along well with C. isnt interested inD. wants to eat( )38. The bad tiger fights with everyone all the time _.A. because others wants to kill himB. because he wants to eat othersC. for no reasonD. because others arent friendly to him( )39. The good tiger can control the grandfather because _.A. the good tiger is much strongerB. the good tiger can get along well with othersC. the grandfather treats the tiger very wellD. the grandfather hates the bad tiger( )40. The writer wants to tell us _ in the passage.A. how to feed tigers wellB. how to control our feelingsC. how to get along with othersD. how to fight with others（B）Anger is a kind of feeling. Many things can make you angry. When your teacher gives you too much homework, when your team loses an important game, when a friend borrows your favorite thing and then breaks it, you may get really angry. Usually, your body will tell you when you are angry. For example, you breathe faster, your face turns red, and you may want to break something or hit(打) someone, but sometimes, you hide(隐藏) your anger. For example, you may hide it in your heart. The problem is that if you do this, you may get a headache or your stomach may hurt. In fact, its not good to hide your anger, and its normal for you to get angry sometimes. But anger must be let out in the right way, without hurting others or yourself. When you get angry, you can talk about it with other people. Its helpful to talk about your anger with an adult, such as parents, a teacher, etc. When you talk about anger, those bad feelings can start to go away. Here are some other things you can do when you start to feel angry: talk to a good friend; count from 1 to 100; give someone a hug(拥抱); go for a bike ride; think about good things, etc. Remember that how you act when you are angry can make everything better or worse. Dont let your anger control you.根据短文内容，选择最佳答案。( )41. You may not get angry when _. A. there is too much homework on this weekendB. your favorite basketball team wins the gameC. a friend breaks your favorite thing D. your parents dont let you watch TV( )42. _ shows that youre not angry. A. Taking a faster breathB. Getting a headacheC. Getting a stomachacheD. Wanting to protect someone( )43. According to the passage, you can do everything when you get angry except(除了) _. A. go for a bike rideB. think about good thingsC. talk to a good friendD. say bad things to the people around you( )44. The underlined word “control” in the last paragraph means _ in Chinese. A. 控制B. 连接C. 帮助D. 失去( )45. This passage is mainly about _. A. angerB. excitementC. happinessD. sadness(C)Dear editor,My English teacher is very strict with us. Several days ago, when we were in class, Tom asked me a question. But my English teacher thought we were speaking in class. She asked us to stand at the back of the classroom for a few minutes. This made me unfair. After that, I feel nervous in her class, so I dont like her class. However, I really want to learn English well. What should I do?Yours,MikeDear Mike,I am sorry you are having difficulty with your English class. Every teacher wants his or her students to study hard. So I think you should have a talk with your English teacher and tell her what you were doing with Tom that day. If she knows your worries, maybe she will help you with your English. And she will be pleased to hear you want to learn English well. Of course, you should know that what your teacher did was good for you. When you are not trying as hard as you can, she has to stop it and try to help you. Wish you have a better life!Yours,Editor根据短文内容，选择最佳答案。( )46. Whats wrong with Mike? A. He doesnt like learning English.B. He meets trouble with his English teacher.C. He doesnt know how to get on well with his English teacher.D. He doesnt like English any longer.( )47. Mike feels nervous in English classes because _.A. he doesnt like his English teacherB.he cant speak in classC. his English teacher punished(惩罚) himD. his English is poor( )48. In the editors opinion, the English teacher asked Mike to stand for a while because _.A. she didnt like himB. she didnt think Mike was learning English hard at that timeC. Mike was bad at English D. Mike was making much noise( )49. The teacher will _ if Mike has a t