教科版九年级上册物理4.1电流 教案.doc

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4.1电流教学设计 一、教学目标1. 知识与技能(1)通过与水流大小的类比了解电流大小的概念。(2)知道电流的单位及其换算关系,了解常见电流值。(3)认识电流表,学会正确使用电流表测量电流值。(4)通过对电流表使用说明书的阅读,提高自学能力。2.过程与方法(1)用类比法学习电流的概念。(2)通过测量小灯泡灯丝中电流值,练习电流表的使用方法3.情感、态度与价值观(1)通过了解安培,树立勤奋学习造福人类的远大理想。(2)在实验中体会成功,培养学习兴趣。(3)学会团队协作,养成科学认真的态度。 二、教学重点、难点1.重点学会正确使用电流表。2.难点学会正确使用电流表。 三、教学器材教师示教板两套,电源(两节干电池)、小灯泡、开关、电流表、导线。四、教学设计播放广州和上海的城市夜景,让学生在领略城市夜景魅力的同时,感受伟大祖国发展的迅速;在对大城市心生向往的同时,也不要忘记其中的电流的功劳,引入本节新课,第四章 探究电流(板书)介绍本章主要学习内容,我们将在本章中学习和了解电学中的三个新朋友电流、电压、和电阻。今天我们先从认识电流开始。可能会有同学有疑问,电流已经是上一单元我们学过的概念了,为什么老师还称之为新朋友呢那么近让我们带着这样的疑问开始我们今天电流的学习吧。(1) 课前回顾回顾我们目前对电流相关问题的掌握情况 1、电荷的 移动形成电流,物理学中规定、 方向为电流的方向。 2、如下图所示的干电池,其右端为 极(选填“正”、“负”);其在电路中供电时能量转化为 。3、在电源外部电流从电源 极出发,经用电器流回 极(选填“正”、“负”);(二)引入新课演示1课件展示缺少电源电路图,提问闭合开关此电路中会有电流通过么(没有,因为没有电源)在电路中加入电源,闭合开关电路中会有电流么怎样判断电路中是否有电流(电路中有电源,形成通路电路中就会有电流,可以通过小灯泡发光反应电路中有电流)教师讲解有电流通过时,小灯泡不仅发光,用手触摸小灯泡还很热,小灯泡是先发热才发光。为什么小灯泡会发热呢电流通过导体时会产生热量,我们把这种现象叫做电流的热效应,根据电流的热效应,我们能判断电流的存在。这里用到了转换法。 演示实验2用一节干电池作电源,演示小灯泡发光实验。用两节干电池作电源,使同一支小灯泡发光。观察并比较两次实验中小灯泡的亮度。发现第二次实验中小灯泡更亮,可得出结论灯泡亮度不同,说明通过灯丝的电流大小不同;同一支灯泡越亮,通过灯丝的电流越大。电流不仅有方向还有大小,提出问题“那么我们如何描述电流的大小呢”引入新课。(三)新授课1.认识电流 (1)通过与水流类比形成电流大小的初步概念。观察水流大小的课件,提问通过观察,你认为哪个水管中水流大(左管)为什么(左管中流过的水量多)教师强调比较水量的多少必须保证时间相等。总结水流大小的概念用每秒钟内通过水管某一横截面的水量的多少,表示水流的大小。观察电流大小的课件,提问每秒钟内通过哪一段导体横截面的电荷更多一些(上面的)请同学们猜测哪段导体中电流更大一些。(上面一段导体中电流更大一些)总结电流大小的概念物理学中用每秒钟通过导体某一横截面的电荷的多少来表示电流的大小。电流的大小用字母I表示。(2)学习电流的单位及换算关系。学生通过阅读课本,学习国际单位制电流的单位是安培,字母A。导学案展示安培简历,以及关于安培的励志故事,鼓励学生勤奋学习,树立为全人类作贡献的远大理想。(3)学习电流的常用单位及换算关系。(4) 多媒体展示常见电流值,指导学生了解常见用电器的电流值。2.电流表(1)观察电流表用途测电流大小 元件符号 电路中有多个电流表时可以加角标如A1;结合电流表的使用说明书及手边的电流表指导学生观察电流表的主要结构,量程、分度值及接线柱的接法。提问1、 你通过那些信息可以知道手中的是一块电流表2、 观察电流表接线柱的特点,如何合理使用它们3、 观察电流表接线柱及表盘上数据的特点你能获得那些信息4、 电流表是带有指针的测量工具使用前要注意哪些问题学生观察、阅读后回答电流表表盘上标有字母A,表示它是一块电流表,字母A还标志了该电流表读数时以A为单位;电流表有三个接线柱,两个正接线柱,分别标有0.6、3字样,一个负接线柱;接入电路中时,必须接一个正接线柱,一个负接线柱;电流表的三个接线柱对应着两个量程0---0.6A和0----3A,对应的分度值分别是0.02A和0.1A;电流表观察指针是否指向零刻度线,如有偏差需要用零点调节器调到零位。(2) 电流表的读数观察完电流表的量程和分度值后,我们就可以解决电流表一个比较常见的问题电流表的读数,当电流表指针稳定的指向某一刻度时,我们就可以读出所测量的电流值。课件展示电流表读数画面,学生尝试读数,并引导学生总结读数的方法1.先明确所选量程及对应分度值;2.闭合开关待指针稳定后在读数;3.读数时视线要正对刻度线。课件展示电流表选择不同量程,指针指向同一刻度线时的画面,引导学生总结规律对比电流表的两个量程、分度值及对应的读数不难发现,大量程的量程、分度值以及读数都是小量程的5倍。课件上在出示几个电流表的读数练习,提升学生的读数能力;并观察右图所示读数,引导学生发现问题,电流表当前指针偏转角度较小,而且选择了0-3A的量程,量程选择不合适,测量误差较大;师生共同总结得出电流表使用关于量程选择的注意问题1、测量前应先估测待测电流的大小,选择适当量程的电流表;2、被测电流不能超出电流表的量程;3、如不能估计电流的大小,可以用较大的量程进行快速试触(3) 电流表的使用了解了使用前观察的内容,也明确了电流表的读数相关问题,接下来,我们一起在探究一下如何将电流表接入电路的问题,电流表想测量通过用电器的电流电流表要被测电路串联,而且电流表串联接入电路后不能影响电路中电流的值,所以电流表对电流的阻碍作用应很小,在分析电路连接时可以看作是导线。所以不允许不经过用电器直接将电流表连接到电源的两极上否则电路中中电路过大会损坏电流表。电流表的三个接线柱对应两个量程,接入电路时应接一个正接线柱一个负接线柱,怎样接入电路,通过教师演示两种接法得出正确的方式;使电流从从电流表的“” 接线柱流入,从“-”接线柱流出,如果使电流从从电流表的“-” 接线柱流入,从“”接线柱流出,电流表的指针就会反向偏转,不仅测不出电流,电流表的指针还会打弯。总结电流表使用方法“两要 两不 两看清”两 要电流表要串联在待测的那部分电路中电流要从“”接线柱流入,从 “-”接线柱流出;两 不不能超过电流表的量程; 不允许把电流表直接连到电源两极上;两看清看清所用的量程;看清分度值;学生小组讨论总结电流表的使用方法,并完成导学案的表格(四)课堂小结由学生总结,教师补充。(五)巩固练习及课后作业 板书设计 4.1电流 一、认识电流 二、测量电流 organization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organization of the basic level organizations advanced model.seven the manual work of the Communist Youth League Organization published and League branch of manual work, to promote the use of two manuals in the citys organizations at various levels. The county committee, directly under the group work is under the jurisdiction of grassroots League and group total using branch ratio shall not be less than 70.Three, to further strengthen the groups leadership and team buildinga to strengthen the leagues leadership at all levels of construction. Continue to do a good job of municipal Party Committee Organization Department on the strengthening of the Communist Youth League cadres management opinions implementation. To promote the group counties autonomous counties, cities Commission and city directly under the group workers appointed to carry out the Five team building activities. Improve the League Association Department working mechanism. Conscientiously fulfill the duties of CO, combined with the city group directly under the Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selection with the work. Do a good job in municipal Party committee assistant committee leadership and leading cadres of the annual assessment work, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation, to strengthen the committees of all levels, the Standing Committee of the Standing Committee, the establishment of a sound system of central group learning, the system of investigation and study, the system of important issues and the reporting system.two to strengthen the work of education and training of cadres to conscientiously implement the Central Committee. On the implementation of grassroots cadres training project and opinions on carrying out the mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres training education. Focus on the county grassroots cadres and workers focused on training, the new school system vocational training League cadres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the construction of new socialist countryside, strengthening village cadres and rural construction team group member of the young team, the county organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village Party branch.three actively promote grassroots cadres election work. Under the unified leadership of the party organization, to strengthen grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elected branch secretary at the same time, actively and steadily the development of Township, streets and other grassroots organizations in the direct election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually ed a set of measures and cadres election system.four to strengthen the cadres testing rcise. To study the development of XX city from 2006 to 2008 cadres testing rcise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in developed areas. With the Central Committee the implementation of the western region and ethnic minorities cadres training plan . To carry out the eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX branch testing rcise.five to strengthen the group construction. The main position to play the role of Youth League cadre education and training as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt arrangement menu course, basic theory includes group work, focus, hot and difficult issues, to enhance the content and practice; to strengthen the construction of teaching staff, the integration of teachers, establish a quality teacher training team, establish and implement course uation system; take delivery of training to the countryside, on-site training, and increase the rural grassroots cadres training efforts.Four, efforts to strengthen the work of young talenta to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization and socialization mechanism. Give full play to the XX award in recognition of 54 youth medal Association, Youth Award winner in the 54 chapter, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognition of the tenth XX young 54 medal. The association of XX editing of young talent , the exchange of ination and communication plat for the XX of outstanding young talents.two the establishment of municipal Party committee of young talent ination database. In accordance with the feasible, effective, classification management, implement step by step principle, the establishment of municipal Party committee of youth talent database; guiding organizations at various levels generally established the young talent database, construction of city, county directly under the Communist Youth League, grassroots organizations three young talent ination database the relevant ination collection system, and gradually establish the citys young people, the Communist Youth League youth talent ination network, provide ination plat for young talent resource development.Five, take effective measures to strengthen the mission managementa to strengthen the mission management work. Strengthen the dues collection and management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one vote veto system audit system. Do statistical work in the group. The group service award in recognition of the advanced units, standardization, promoting group management work institutionalized.two to strengthen the organization of research and ination exchange efforts. Grassroots carry out research, efforts to a number of theoretical results. Make full use of the network carrier, to explore the establishment of electronic group service system, promote the work of Communist Youth League ination.Attachment 4XX municipal Party Committee Propaganda Department of the Communist Youth League work pointsIn 2006, the Communist Youth League propaganda ideological work XX to Deng Xiaoping theory and the important thought of Three Represents as guidance, study and implement the partys sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implementation of the eight plenary session of the two committee, the citys cultural work conference, the Propaganda Department of the meeting and the the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around 11th Five-Year XX the goal of full implementation of Scientific Outlook on Development, emancipating the mind, seeking truth from facts, keep pace with the times, close to reality, close to life, close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the groups propaganda and ideological work ability, unity To guide the majority of members of the youth to achieve the 11th Five-Year planning tasks, the overall construction of a well-off society, building a socialist harmonious society to make new contributions.One, adhere to the Three Represents important thought and Scientific Outlook on Development education to guide the youth, to further strengthen the ideological and political education of youtha armed with youth science theory. Unremittingly with Deng Xiaoping theory and the important thought of Three Represents armed members of youth education, to promote the study and implement to expand the depth and breadth. To study and implement the important thought of Three Represents with the establishment and implementation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Outlook on Development, carry out education as an important part of the theory of armed youth in the new period, strengthen the establishment and implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and implementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Development era back The king, the practice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with Marxism Leninism, Mao Zedong thought, inheriting and developing relationship between Deng Xiaoping theory and the important thought of Three Represents, to help young people establish and consciously practice Scientific Outlook on Development. Persist in learning, grasping the backbone, grasp the practice, grasp the opportunity. Catch club, effective way to grasp the network, with the group of cadres, young students and young backbone fronts as the focus, to promote the work of the armed youth theory to develop in depth, to help the youth continue to firm ideals and beliefs, to build a powerful spiritual pillar. To carry out the study and implementation of the partys sixteen session of the five Eight plenary session of the two plenary session of the Central Committee and the party spirit, to the citys Youth League members thinking into the spirit of the meeting, to achieve the goal of national consciousness and XX economic and social development in 11th Five-Year period. Contribute to help and guide the youth to a profound understanding of the significance and main task of building a socialist harmonious society, actively join the construction of socialist harmonious society.two to strengthen the ideological and moral construction of teenagers. Thoroughly implement the central spirit of the document No. 8, No. 16 and the program for Improving Civic Morality to minors and students as focus groups, to strengthen and improve the ideological and moral construction of minors and the ideological and political education of college students. Make full use of the spirit and the spirit of the Three Gorges migrants Hongyan XX unique the use of educational resources, school, into the team, the league, to join the party, adult occasions, extensive Hongyan spirit generation theme education activities. Use of holidays and leisure time, youth org
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