(完整)人教版高一物理必修一第三章教案

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the party's fine style, carry forward the traditional Chinese virtues, practicing the Socialist core values, vigorously carry forward the spirit of Jiao Yulu, Hongqi Canal spirit and spirit of persistence, honesty in politics, strict statesman, stick to the spiritual heights of the Communists. Four to devotion, as, do play a role in qualifying. Official Communist duty. To fulfill the party's purpose, maintain for the people themselves, and dedication, devotion, maintain pioneer, pioneering and enterprising spirit, active at the well-off extra practice, make contributions. The incentive function of party organizations at all levels should give full play to advanced models, establish a representative, advanced and typical of the times, and guide the broad masses of party members to emulate. In honor of the 95 anniversary of founding as an opportunity to award in recognition of a number of outstanding party members ' advanced grass-roots party organizations, outstanding party workers, and put the pioneer trees. Third, the \o change into. Learning to teachEducation in order to solve the problem, if it does not solve the problem, it wilform, goes through the motions. To strengthen the consciousness of problems and insisted on problem-oriented, problem-solving learning education for traction, truly deep investigation into change, modification. A checked swing. Learning education programme for party-building in our city actually proposed to focus on solution of fuzzy ideals and beliefs waver, consciousness, purpose of the party weak sense, honesty and self-discipline awareness is not strong, depressed, six issues of ethical misconduct study contents specific programmes for all party members and leading cadres above the county level shall focus on further refinement to the problems. Specific to every party member and every cadre, also requires a combination of actual and controlled, focused and really put yourself in, people see things, see, with their own specific problems to learn Constitution Party rules, series, address, so precision to find the problem, laying a solid foundation for further corrective action. B to make change. For check put of problem, through established rectification aiwan account, and take special supervision, and on account PIN,, approach, insisted do sidelearn side modified, and that know that modified, while focused on put \arn a do\ng education rectification with grasp party of mass line education practice activities and \hree real\c education problem rectification combined up, consolidation expanded has made of rectification results, strongly corrected \ind\nd regulation masses side of abuses, ensure work advance more powerful, and problem solution more completely. Third, we must consolidate our achievements. For more public, some party members who focus on the outstanding issues, combining concentrated3.1重力基本相互作用

【教学目标】

1、知识与技能

⑴知道力的作用效果可分为两类。

⑵理解力产生的条件，知道力的测量工具、单位、量性、力的图示。 ⑶知道重力是由于物体受到地球的吸引而产生的。

⑷知道重力的大小和方向。会用公式G＝mg（g＝9.8N/kg）计算重力。

⑸知道用悬绳挂着的静止物体、用水平支持物支持的静止物体，对竖直悬绳的拉力或对水平支持物的压力，大小等于物体受到的重力。

⑹知道重心的概念以及质量分布均匀的物体重心的位置。 ⑺了解力的几种基本相互作用，会对不同的力进行分类。 2、过程与方法

⑴让学生自己动手，找不规则薄板的中心培养学生动手的能力。

⑵通过“重心”的概念，让学生知道等效替代是物理学研究的一种方法。 3、情感、态度价值观

⑴通过课本内容的完成，让学生自己动手、动脑、观察，教育学生在日常生活当中多观察、多分析，看问题不能片面。【教学重点】

⑴重点：重力的大小和方向。重心的概念。 ⑵ 教学策略：实验探索、观察思考、实际演练加深对问题的理解。【教学难点】

⑴难点：重心概念的理解。g值因在地球的不同纬度而不同。 ⑵教学策略：通过讲解、对问题的讨论，引导学生解决问题。【教学方法】

实验、与启发式讲练相结合。

【教具准备】

弹簧秤、钩码、质量均匀的不规则薄板、细绳、木圆环、直角三角尺、重锤线

新课教学引入：

同学们都平时都习惯这样说，我们班要数某某同学的力量最大，某某同学脚部的力量最强，一脚可以把足球开出五、六十米。这种对力的说法符合物理角度对力的定义吗？本节课我们将着手研究这个问题，并学习几种简单的力学问题。一．力概念的引入和力的性质

问题{叫学生看书51叶第一段话回答}物体的运动状态说明物体什么量在发生改变：总结：物体的速度改变?物体的运动状态改变

例：在足球场上，守门员大脚开球，球由静止变为运动；守门员接住球时，球由运动变为静止；运动员用头顶球，球的方向改变了。这些都是什么现象，是什么原因造成的呢？

（学生老师谈论）这些都是球运动状态改变的现象；球运动状态改变都是运动员对球作用的结果。例：演示1、用手压锯条、拉皮筋等，学生观察现象，是什么原因导致这种变化呢？

演示2、扔掉手中的粉笔，拖动桌面上的书等，又有什么现象，又是什么原因引起这样的变化呢？

锯条、皮筋的形状发生了改变，球，粉笔、书的运动状态发生了改变，这些都是由于这些物体受到了其他物体的力的作用的结果。在物理学中，人们把改变物体的运动状态，产生形变的原因，即物体与物体之间的相互作用称作力。

rectification and strengthening the management of daily education, the spirit of reform short of the complete system, pay close attention to system implementation, really make the party organization and party member education and strict management, solid. Finally, the \on the lead, be sure to promote efficiency. \ducation, not on education educational, not working with the Centre two, must stick around the Center, serving the overall situation, coordinate, truly result-oriented and promote efficiency. Current and future a period, to tightly around coordination advance \out, winning full built society this a central and work overall, put carried out learning education as promoted work of important opportunities and powerful power, guide General members cadres insisted development first priority, active adapted economic development new normal, consciously practice line five big development concept, effective grasp supply side structural reform, to guarantees and improved livelihood, construction more high ecological vitality happiness of city. Last year, we carry out \-three\ctivities as a\cial education important, find education and effective platform to facilitate the combination of work. Reference this a good practices, provincial, and municipal decided in \two learn a do\ng education in the carried out \ck five promoting%units to insisted put \do\ning education and \omoting\nic fusion, and common advance, do one plan layout, and one organization implementation, put carried out \n a do\ck five promoting\on as party work evaluation of importantContent, as an important aspect of mutual evaluation on party members, testing as an important basis for leading bodies and leading cadres ' performance and guide the broad masses of party members and cadres to study education opens up to the main economic and social development. At present, the overall smooth economic operation in our city, but downward pressure is still high, faced a number of challenges and tests. Meanwhile, coincides with the city, County and township party committees this year general election year, how to really choose loyal, clean and serves as a good cadre, iron discipline of General Feng Qing Qi, Qi, Qi Shun, swapped out Powerful good situation, is a real test for all of us. General work on %udy the effect of education inspection, if the true series of party rules and Constitution speaks well and truly become a qualified party member, naturally we can deal with advance and retreat left turn treatment, proper organizational arrangements and selecton, proper treatment of personal interests. o put carried out \arn a do\ng education with do reform development stable the work combined up, and seriously do Center work, and daily and job combined up, and guarantees improved livelihood, and promote social harmony combined up, and completed the task combinedthe party's fine style, carry forward the traditional Chinese virtues, practicing the Socialist core values, vigorously carry forward the spirit of Jiao Yulu, Hongqi Canal spirit and spirit of persistence, honesty in politics, strict statesman, stick to the spiritual heights of the Communists. Four to devotion, as, do play a role in qualifying. Official Communist duty. To fulfill the party's purpose, maintain for the people themselves, and dedication, devotion, maintain pioneer, pioneering and enterprising spirit, active at the well-off extra practice, make contributions. The incentive function of party organizations at all levels should give full play to advanced models, establish a representative, advanced and typical of the times, and guide the broad masses of party members to emulate. In honor of the 95 anniversary of founding as an opportunity to award in recognition of a number of outstanding party members ' advanced grass-roots party organizations, outstanding party workers, and put the pioneer trees. Third, the \sure to change into. Learning to teachEducation in order to solve the problem, if it does not solve the problem, it wilform, goes through the motions. To strengthen the consciousness of problems and insisted on problem-oriented, problem-solving learning education for traction, truly deep investigation into change, modification. A checked swing. Learning education programme for party-building in our city actually proposed to focus on solution of fuzzy ideals and beliefs waver, consciousness, purpose of the party weak sense, honesty and self-discipline awareness is not strong, depressed, six issues of ethical misconduct study contents specific programmes for all party members and leading cadres above the county level shall focus on further refinement to the problems. Specific to every party member and every cadre, also requires a combination of actual and controlled, focused and really put yourself in, people see things, see, with their own specific problems to learn Constitution Party rules, series, address, so precision to find the problem, laying a solid foundation for further corrective action. B to make change. For check put of problem, through established rectification aiwan account, and take special supervision, and on account PIN,, approach, insisted do sidelearn side modified, and that know that modified, while focused on put \arn a do\ng education rectification with grasp party of mass line education practice activities and \hree real\c education problem rectification combined up, consolidation expanded has made of rectification results, strongly corrected \ind\nd regulation masses side of abuses, ensure work advance more powerful, and problem solution more completely. Third, we must consolidate our achievements. For more public, some party members who focus on the outstanding issues, combining concentrated1、力的定义：物体与物体之间的相互作用。

问题：你们初中学国的力有什么性质呢？

举例：我们用手拍打桌子时，是手给桌子一个力，可为什么我们的手也会感到疼痛呢？（让学生用力打桌子，体会手的感觉）举例：不小心两人碰头，谁头先痛? （1）、相互性

力是物体间的相互作用，甲对乙有作用力，同时乙对甲也有力的作用，力的作用是相互的。（2）、力的物质性

力是物体对物体的作用，有力就有受力物体和施力物体，两者是同时存在的，不分先后。在研究某物体时，我们把它叫做受力物体，对它作用的物体叫做施力物体。不是有生命的物体才能作为施力物体，施力物体和受力物体不是绝对的，在研究不同问题时，同一物体有时是受力物体，有时是施力物体。问题：用大小相等的力沿不同的方向拖动桌面上的书，书的运动一样吗？（3）、矢量性

力是有大小和方向的物理量（矢量），力的大小可以用测力计或弹簧称测量，力的单位：牛顿符号N。1N到底有多大？

1千克的物体受的重力是9.8N。一斤是500克受到的重力是4.9N。一本书大约是290到300克重约3N

问题：力的作用效果有那些？举例说明。 2、力的作用效果

力可以使物体发生形变和运动状态发生改变（包括速度的大小和方向）。

演示：关门时，在不同的地方施加不同方向和大小的力，产生的效果不一样，说明了力的作用效果与那些因素有关？ 3．力的三要素

大小、作用点、方向

问题：我们可以怎样把力的三要素完整的表示出来呢？ 4．力的图示和示意图

例：一个重150N的物体静止放在水平地面上，叫学生上黑板上画出物体重力的图示和示意图。老师总结：力的图示：按一定的比例作出的带有箭头的线段。

线段的长短代表力的大小，箭头的方向代表力的作用方向，箭头或箭尾代表力的作用点。

有时只需要画出力的示意图，即只画出力的作用点和方向，表示这个物体在这个方向上受到了力。二、重力

提问：重力是怎样产生的？

学生在预习后回答：地球上的一切物体都要受到地球的吸引，所以人跳起来总会落在地上，扔出去的东西总要落回地面。提问：有的同学说物体的重力就是地球的吸引力，到底是不是呢？学生猜疑：有的说是，有的说不是。

教师释疑：严格地说，重力并不是地球的吸引力，而是吸引力的一部分，以后才会学到这些知识，现在知道就行了。所以说重力是由于地球的吸引而使物体受到的力，而不能说地球的吸引力就是物体的重力。由于两者相差很小，通常可以用重力代替吸引力。

⑴概念：由于地球对物体的吸引而使物体受到的力，叫做重力。重力就是重量。一个物体受到10N的重力，可以说这个物体的重量是10N。提问：重物受到的重力的施力物体和受力物体各是谁？学生：施力物体是地球，受力物体是重物。

强调：地球上的任何物体在任何状态下都受到重力的作用。因此，在今后的受力分析中重力肯定有。在月球上，物体也会由于月球的吸引而受到相应的重力，到其他星球表面也一样。 ⑵产生条件：是由于地球的吸引。 ⒊重力的大小和方向

clean and serves as a good cadre, iron discipline of General Feng Qing Qi, Qi, Qi Shun, swapped out Powerful good situation, is a real test for all of us. General work on %udy the effect of education inspection, if the true series of party rules and Constitution speaks well and truly become a qualified party member, naturally we can deal with advance and retreat left turn treatment, proper organizational arrangements and selection, proper treatment of personal interests. o put carried out \arn a do\ng education with do reform development stable the work combined up, and seriously do Center work, and daily and job combined up, and guarantees improved livelihood, and promote social harmony combined up, and completed the task combined2

the party's fine style, carry forward the traditional Chinese virtues, practicing the Socialist core values, vigorously carry forward the spirit of Jiao Yulu, Hongqi Canal spirit and spirit of persistence, honesty in politics, strict statesman, stick to the spiritual heights of the Communists. Four to devotion, as, do play a role in qualifying. Official Communist duty. To fulfill the party's purpose, maintain for the people themselves, and dedication, devotion, maintain pioneer, pioneering and enterprising spirit, active at the well-off extra practice, make contributions. The incentive function of party organizations at all levels should give full play to advanced models, establish a representative, advanced and typical of the times, and guide the broad masses of party members to emulate. In honor of the 95 anniversary of founding as an opportunity to award in recognition of a number of outstanding party members ' advanced grass-roots party organizations, outstanding party workers, and put the pioneer trees. Third, the \sure to change into. Learning to teachEducation in order to solve the problem, if it does not solve the problem, it wilform, goes through the motions. To strengthen the consciousness of problems and insisted on problem-oriented, problem-solving learning education for traction, truly deep investigation into change, modification. A checked swing. Learning education programme for party-building in our city actually proposed to focus on solution of fuzzy ideals and beliefs waver, consciousness, purpose of the party weak sense, honesty and self-discipline awareness is not strong, depressed, six issues of ethical misconduct study contents specific programmes for all party members and leading cadres above the county level shall focus on further refinement to the problems. Specific to every party member and every cadre, also requires a combination of actual and controlled, focused and really put yourself in, people see things, see, with their own specific problems to learn Constitution Party rules, series, address, so precision to find the problem, laying a solid foundation for further corrective action. B to make change. For check put of problem, through established rectification aiwan account, and take special supervision, and on account PIN,, approach, insisted do sidelearn side modified, and that know that modified, while focused on put \arn a do\ng education rectification with grasp party of mass line education practice activities and \hree real\c education problem rectification combined up, consolidation expanded has made of rectification results, strongly corrected \ind\nd regulation masses side of abuses, ensure work advance more powerful, and problem solution more completely. Third, we must consolidate our achievements. For more public, some party members who focus on the outstanding issues, combining concentrated提问：重力的大小可以用弹簧秤来测量，为什么？学生：物体静止时对弹簧秤的拉力大小等于其重力。

实验：手提弹簧称及其下挂的钩码，测出钩码的重力；在竖直方向上用不同的方式运动，观察弹簧称示数及其变化。

(引导学生根据实验，并结合二力平衡知识得出结论) ⑴重力的大小：

重力的大小可以用弹簧秤测出。

在静止的情况下，物体对竖直悬绳的拉力或对水平支持物的压力，在数值上等于物体重力的大小。问：以上的这种情况这样说对不对：悬绳的拉力就是重力？

动手实验：用弹簧秤测量一个钩码、两个钩码、三个钩码的重力的大小，观察计算重力G与钩码的质量m的关系。

学生马上得到：G与m成正比。

重力大小与物体质量关系： G＝mg（g＝9.8N/kg）

强调：g值在地球的不同位置取值不同，一般情况下忽略这个差异，可认为g值是恒定的。实验：从静止释放的小石块总是竖直下落，重锤线的方向总是竖直向下。归纳：从静止释放的小石块总是竖直下落，分析重锤线下重物的受力情况，可知重力的方向竖直向下。 ⑵重力的方向：总是竖直向下。

强调：竖直向下不能说成垂直向下，竖直向下指的是与水平地面相垂直，不能笼统指垂直方向。

? 巩固训练（叫学生上黑板上画此图的重力示意图）

①物体静止在水平桌面上，物体对水平桌面的压力（B D） A、就是物体的重力 B、大小等于物体的重力

G C、这压力是由于地球的吸引产生的 D、这压力是竖直向下的

②物体静止在斜面上，物体所受重力的方向如图所示，这样表示对吗？（请学生分析） ⒋重心 ⑴概念

物体的各部分都受到重力的作用。从效果上看，可以认为物体各部分受到的重力作用集中于一点，或各部分重力的等效作用点，或各部分所受到的重力的合力的作用点，叫物体的重心。

通俗点讲，重心就是重力的作用点。把物体的全部质量集中到一点将不影响研究结果，这就是物理学的一种等效替代的思想。

⑵与重心位置有关的因素： ①与物体的形状有关；

②与物体的质量分布有关。

质量分布均匀的物体的重心，跟物体的形状有关。

质量分布均匀的有规则形状的物体，其重心在此几何中心上。

同学们在初中知识的基础上，找出这些质量分布均匀的物体的重心（投影分析）

质量分布均匀的形状不规则的薄板形物体的重心可用二次悬挂法或寻找支点法找到。

the party's fine style, carry forward the traditional Chinese virtues, practicing the Socialist core values, vigorously carry forward the spirit of Jiao Yulu, Hongqi Canal spirit and spirit of persistence, honesty in politics, strict statesman, stick to the spiritual heights of the Communists. Four to devotion, as, do play a role in qualifying. Official Communist duty. To fulfill the party's purpose, maintain for the people themselves, and dedication, devotion, maintain pioneer, pioneering and enterprising spirit, active at the well-off extra practice, make contributions. The incentive function of party organizations at all levels should give full play to advanced models, establish a representative, advanced and typical of the times, and guide the broad masses of party members to emulate. In honor of the 95 anniversary of founding as an opportunity to award in recognition of a number of outstanding party members ' advanced grass-roots party organizations, outstanding party workers, and put the pioneer trees. Third, the \sure to change into. Learning to teachEducation in order to solve the problem, if it does not solve the problem, it wilform, goes through the motions. To strengthen the consciousness of problems and insisted on problem-oriented, problem-solving learning education for traction, truly deep investigation into change, modification. A checked swing. Learning education programme for party-building in our city actually proposed to focus on solution of fuzzy ideals and beliefs waver, consciousness, purpose of the party weak sense, honesty and self-discipline awareness is not strong, depressed, six issues of ethical misconduct study contents specific programmes for all party members and leading cadres above the county level shall focus on further refinement to the problems. Specific to every party member and every cadre, also requires a combination of actual and controlled, focused and really put yourself in, people see things, see, with their own specific problems to learn Constitution Party rules, series, address, so precision to find the problem, laying a solid foundation for further corrective action. B to make change. For check put of problem, through established rectification aiwan account, and take special supervision, and on account PIN,, approach, insisted do sidelearn side modified, and that know that modified, while focused on put \arn a do\ng education rectification with grasp party of mass line education practice activities and \hree real\c education problem rectification combined up, consolidation expanded has made of rectification results, strongly corrected \ind\nd regulation masses side of abuses, ensure work advance more powerful, and problem solution more completely. Third, we must consolidate our achievements. For more public, some party members who focus on the outstanding issues, combining concentrated学生动手找自己的不规则薄板的中心，并且说出其原理。

教师演示：木圆环，不规则形状薄木板的重心。（参照课本中P5的实验）验证：用悬挂法确定重心之后，在板上固定一条细线，让其穿过重心C点，再在其重心C处拴上细绳提拉，验证薄板可以水平平衡。也可以重心C为支点，让薄板水平平衡。

演示讲解：不倒翁的制作就是改变椭圆空腔的重心，增强对重心概念的印象。

演示：将一段均匀的直铁丝，做成直角、四边形、圆形等不同的形状，用悬挂法寻找其重心的位置。归纳：物体的重心可在物体之上，也可在物体之外。物体的稳定程度与重心的高低及支承面的大小等有关。

简单介绍一下不倒翁的原理，让学生有一种印象，为以后学习平衡的种类奠定基础。

巩固练习：用卡车运输一些有的轻、有的重物体，将这些物体怎样堆放到卡车上较为合理。 (尽量将重的物体放在车的底部，整体的重心较低，行驶较安全) 一、基本相互作用

引力相互作用是是所有物体之间都存在的一种相互作用。对于通常大小的物体，它们之间的引力非常微弱，常被忽略不计。

电磁相互作用包括静止电荷之间以及运动电荷之间的相互作用。电和磁是密切相关的，在一个参考系中观察到的磁力可以和另一个参考系中的电力联系起来，电力和磁力可统一为电磁相互作用。

引力和电磁力能在宏观世界里显示其作用。这两种力是长程力，从理论上说，它们的作用范围是无限的。但是，电磁力要比引力强得多。宏观物体之间的相互作用，除引力外，所有接触力都是大量原子、分子之间电磁相互作用的宏观表现。

-15

强相互作用和弱相互作用都是短程力。短程力的作用范围在原子核尺度内。强作用力只在10m范围

-16

内有显著作用，弱作用力的作用范围不超过10m。这两种力只有在原子核内部和基本粒子的相互作用中才显示出来，在宏观世界里不能觉察它们的存在。核子（质子、中子）、电子和中微子等参与弱相互作用。强相互作用是介子和重子（包括质子、中子）之间的相互作用，因为这种力将核子束缚在一起，核物理学家们把它称为核相互作用。

三、小结

本节课在初中知识的基础上学习了重力的概念、产生的条件以及重力与引力的区别。

知道了重力大小的测量和用G＝mg来确定，知道了重力的方向；学习了重心的概念，知道了与重心有关的因素及重心的确定方法。

C C rectification and strengthening the management of daily education, the spirit of reform short of the complete system, pay close attention to system implementation, really make the party organization and party member education and strict management, solid. Finally, the \d, be sure to promote efficiency. \on, not on education educational, not working with the Centre two, must stick around the Center, serving the overall situation, coordinate, truly result-oriented and promote efficiency. Current and future a period, to tightly around coordination advance \ng full built society this a central and work overall, put carried out learning education as promoted work of important opportunities and powerful power, guide General members cadres insisted development first priority, active adapted economic development new normal, consciously practice line five big development concept, effective grasp supply side structural reform, to guarantees and improved livelihood, construction more high ecological vitality happiness of city. Last year, we carry out \e-three\\cial education important, find education and effective platform to facilitate the combination of work. Reference this a good practices, provincial, and municipal decided in \do\ng education in the carried out \omoting\strict units to insisted put \do\ng education and \ive check five promoting\c fusion, and common advance, do one plan layout, and one organization implementation, put carried out \arn a do\on, and \ck five promoting\on as party work evaluation of importantContent, as an important aspect of mutual evaluation on party members, testing as an important basis for leading bodies and leading cadres ' performance and guide the broad masses of party members and cadres to study education opens up to the main economic and social development. At present, the overall smooth economic operation in our city, but downward pressure is still high, faced a number of challenges and tests. Meanwhile, coincides with the city, County and township party committees this year general election year, how to really choose loyal,

the party's fine style, carry forward the traditional Chinese virtues, practicing the Socialist core values, vigorously carry forward the spirit of Jiao Yulu, Hongqi Canal spirit and spirit of persistence, honesty in politics, strict statesman, stick to the spiritual heights of the Communists. Four to devotion, as, do play a role in qualifying. Official Communist duty. To fulfill the party's purpose, maintain for the people themselves, and dedication, devotion, maintain pioneer, pioneering and enterprising spirit, active at the well-off extra practice, make contributions. The incentive function of party organizations at all levels should give full play to advanced models, establish a representative, advanced and typical of the times, and guide the broad masses of party members to emulate. In honor of the 95 anniversary of founding as an opportunity to award in recognition of a number of outstanding party members ' advanced grass-roots party organizations, outstanding party workers, and put the pioneer trees. Third, the \sure to change into. Learning to teachEducation in order to solve the problem, if it does not solve the problem, it wilform, goes through the motions. To strengthen the consciousness of problems and insisted on problem-oriented, problem-solving learning education for traction, truly deep investigation into change, modification. A checked swing. Learning education programme for party-building in our city actually proposed to focus on solution of fuzzy ideals and beliefs waver, consciousness, purpose of the party weak sense, honesty and self-discipline awareness is not strong, depressed, six issues of ethical misconduct study contents specific programmes for all party members and leading cadres above the county level shall focus on further refinement to the problems. Specific to every party member and every cadre, also requires a combination of actual and controlled, focused and really put yourself in, people see things, see, with their own specific problems to learn Constitution Party rules, series, address, so precision to find the problem, laying a solid foundation for further corrective action. B to make change. For check put of problem, through established rectification aiwan account, and take special supervision, and on account PIN,, approach, insisted do sidelearn side modified, and that know that modified, while focused on put \arn a do\ng education rectification with grasp party of mass line education practice activities and \hree real\c education problem rectification combined up, consolidation expanded has made of rectification results, strongly corrected \ind\nd regulation masses side of abuses, ensure work advance more powerful, and problem solution more completely. Third, we must consolidate our achievements. For more public, some party members who focus on the outstanding issues, combining concentrated3-2.弹力

教学目标：知识与技能：

1、理解弹力的概念，知道弹力产生的原因和条件.

2、知道压力、支持力、绳的拉力都是弹力，会分析弹力的方向，能正确画出弹力的示意图.

3、理解形变概念，了解放大法显示微小形变. 过程与方法：

通过观察微小变化的实例，初步接触“放大的方法” 情感态度与价值观：

通过探究弹力与形变的关系以及数据的准确记录，培养学生锲而不舍的探究的精神和求真务实的科学精神。

二、重点难点

判断弹力的有无以及弹力的方向既是本节的重点，也是难点.正确画出物体所受弹力的示意图是突破难点的标志.

三、教学方法

观察、推理、分析、综合、总结规律教学用具：

弹簧、海绵、薄竹片、微小形变演示仪教学步骤：一、导入新课

在运动场上跳远时要用踏跳板，撑杆跳高运动员的杆，都是利用他们弹性形变时的弹力，同学们还可以举出许多利用弹力得力子，谁来说？