电阻定律课件.ppt

1、第六节第六节 电阻定律电阻定律第二章第二章 恒定电流恒定电流与长度有关与长度有关与横截面积有与横截面积有关关与材料有关与材料有关结论：导体的电阻和导体的长度、结论：导体的电阻和导体的长度、横截面积、材料有关。横截面积、材料有关。一、实验探究：一、实验探究：1、明确目的：、明确目的：探究电阻与导体的材料、横截面积、长探究电阻与导体的材料、横截面积、长度之间的关系。度之间的关系。2、实验方法：、实验方法：控制变量法。控制变量法。3、实验控制：、实验控制：（1）电阻、长度、横截面积的测量、）电阻、长度、横截面积的测量、测定方法：测定方法：横截面积：绕制线圈先算直径。横截面积：绕制线圈先算直径。长度：

2、直接测量。长度：直接测量。电阻：伏安法。电阻：伏安法。伏安法测电阻的原理图：伏安法测电阻的原理图：（2）器材选择：（电源，开关，电表，导）器材选择：（电源，开关，电表，导线，待测电阻）线，待测电阻）材料、长度一定：材料、长度一定：AB材料、横截面积材料、横截面积一定：一定：CA长度、横截面长度、横截面积一定：积一定：AD（3）实验电路：）实验电路：结论：导体的电阻跟长度成正比，跟横结论：导体的电阻跟长度成正比，跟横截面积成反比，还跟材料有关。截面积成反比，还跟材料有关。二、逻辑推理探究：二、逻辑推理探究：1、分析导体电阻与它的长度的关系。、分析导体电阻与它的长度的关系。2、分析导体电阻与它的横

3、截面积的关、分析导体电阻与它的横截面积的关系。系。3、实验探究导体电阻与材料的关系。、实验探究导体电阻与材料的关系。三、电阻定律：三、电阻定律：1、表达式：、表达式：slR2、适用条件：温度一定，粗细均匀的金属、适用条件：温度一定，粗细均匀的金属导体，或浓度均匀的电解质溶液。导体，或浓度均匀的电解质溶液。3、电阻率：、电阻率：（1）、物理意义：反映导体导电性能的物）、物理意义：反映导体导电性能的物理量。理量。（2）计算表达式：）计算表达式：lRS几种导体材料在几种导体材料在20OC时的电阻率时的电阻率/（m)银银 1.6 10-8铜铜 1.7 10-8铝铝 2.9 10-8钨钨 5.3 10-

4、8铁铁 1.0 10-7锰铜合金锰铜合金 4.4 10-7镍铜合金镍铜合金 5.0 10-7镍铬合金镍铬合金 1.0 10-6（3）电阻率与温度的关系）电阻率与温度的关系：金属电阻率随温度升高而增大。应用：电阻金属电阻率随温度升高而增大。应用：电阻温度计。温度计。半导体的电阻率随温度的升高而减小。应用：半导体的电阻率随温度的升高而减小。应用：热敏电阻，光敏电阻。热敏电阻，光敏电阻。部分合金如锰铜、镍铜电阻率几乎不受温度部分合金如锰铜、镍铜电阻率几乎不受温度的影响。应用：标准电阻。的影响。应用：标准电阻。超导体：某些材料当温度降低到一定温度时，超导体：某些材料当温度降低到一定温度时，电阻率为零。

5、电阻率为零。电阻温度计实验探究实验探究逻辑推理逻辑推理探究探究电阻定律电阻定律表达式表达式电阻率电阻率重视：重视：1、探究思想、探究方法。、探究思想、探究方法。2、实验的控制。、实验的控制。1、金属铂的电阻值对温度的高低非常、金属铂的电阻值对温度的高低非常“敏感敏感”，图中可能表示金属铂，图中可能表示金属铂电阻的图线的是：电阻的图线的是：练习练习2、相距、相距40km的的A、B两地架两条输电线，两地架两条输电线，电阻共为电阻共为800，如果在，如果在A、B间的某处发生间的某处发生短路，这时接在短路，这时接在A处的电压表示数为处的电压表示数为10V，电，电流表的示数为流表的示数为40mA，求发生

6、短路处距，求发生短路处距A处有处有多远？如图多远？如图2所示。所示。第六节第六节 电阻定律电阻定律第二章第二章 恒定电流恒定电流与长度有关与长度有关与横截面积有与横截面积有关关与材料有关与材料有关结论：导体的电阻和导体的长度、结论：导体的电阻和导体的长度、横截面积、材料有关。横截面积、材料有关。一、实验探究：一、实验探究：1、明确目的：、明确目的：探究电阻与导体的材料、横截面积、长探究电阻与导体的材料、横截面积、长度之间的关系。度之间的关系。2、实验方法：、实验方法：控制变量法。控制变量法。3、实验控制：、实验控制：（1）电阻、长度、横截面积的测量、）电阻、长度、横截面积的测量、测定方法：测定

7、方法：横截面积：绕制线圈先算直径。横截面积：绕制线圈先算直径。长度：直接测量。长度：直接测量。电阻：伏安法。电阻：伏安法。伏安法测电阻的原理图：伏安法测电阻的原理图：（2）器材选择：（电源，开关，电表，导）器材选择：（电源，开关，电表，导线，待测电阻）线，待测电阻）材料、长度一定：材料、长度一定：AB材料、横截面积材料、横截面积一定：一定：CA长度、横截面长度、横截面积一定：积一定：AD（3）实验电路：）实验电路：结论：导体的电阻跟长度成正比，跟横结论：导体的电阻跟长度成正比，跟横截面积成反比，还跟材料有关。截面积成反比，还跟材料有关。二、逻辑推理探究：二、逻辑推理探究：1、分析导体电阻与它的

8、长度的关系。、分析导体电阻与它的长度的关系。2、分析导体电阻与它的横截面积的关、分析导体电阻与它的横截面积的关系。系。3、实验探究导体电阻与材料的关系。、实验探究导体电阻与材料的关系。三、电阻定律：三、电阻定律：1、表达式：、表达式：slR2、适用条件：温度一定，粗细均匀的金属、适用条件：温度一定，粗细均匀的金属导体，或浓度均匀的电解质溶液。导体，或浓度均匀的电解质溶液。3、电阻率：、电阻率：（1）、物理意义：反映导体导电性能的物）、物理意义：反映导体导电性能的物理量。理量。（2）计算表达式：）计算表达式：lRS几种导体材料在几种导体材料在20OC时的电阻率时的电阻率/（m)银银 1.6 10

9、-8铜铜 1.7 10-8铝铝 2.9 10-8钨钨 5.3 10-8铁铁 1.0 10-7锰铜合金锰铜合金 4.4 10-7镍铜合金镍铜合金 5.0 10-7镍铬合金镍铬合金 1.0 10-6（3）电阻率与温度的关系）电阻率与温度的关系：金属电阻率随温度升高而增大。应用：电阻金属电阻率随温度升高而增大。应用：电阻温度计。温度计。半导体的电阻率随温度的升高而减小。应用：半导体的电阻率随温度的升高而减小。应用：热敏电阻，光敏电阻。热敏电阻，光敏电阻。部分合金如锰铜、镍铜电阻率几乎不受温度部分合金如锰铜、镍铜电阻率几乎不受温度的影响。应用：标准电阻。的影响。应用：标准电阻。超导体：某些材料当温度降

10、低到一定温度时，超导体：某些材料当温度降低到一定温度时，电阻率为零。电阻率为零。电阻温度计实验探究实验探究逻辑推理逻辑推理探究探究电阻定律电阻定律表达式表达式电阻率电阻率重视：重视：1、探究思想、探究方法。、探究思想、探究方法。2、实验的控制。、实验的控制。1、金属铂的电阻值对温度的高低非常、金属铂的电阻值对温度的高低非常“敏感敏感”，图中可能表示金属铂，图中可能表示金属铂电阻的图线的是：电阻的图线的是：练习练习2、相距、相距40km的的A、B两地架两条输电线，两地架两条输电线，电阻共为电阻共为800，如果在，如果在A、B间的某处发生间的某处发生短路，这时接在短路，这时接在A处的电压表示数为处

11、的电压表示数为10V，电，电流表的示数为流表的示数为40mA，求发生短路处距，求发生短路处距A处有处有多远？如图多远？如图2所示。所示。教师说课PPT1 教材分析2 学情分析3 教学理念4 教学方法5 教学过程 教学反思More than 50%of your traffic comes from social media platforms.So how do you go about executing a content strategy AND keep track of whats trending?Here are a few tools to make the going eas

12、y教学重点教学难点高龄游客的特征如何灵活提供服务教学目标!Click here to add your text.Click here to add your text.Click here to add your text.知识目标01能力目标02情感目标03Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.学

13、情 分析 单击此处添加您的标题文字单击此处添加您的标题文字单击1.学生原有的基础单击此处添加您的标题文字单击此处添加您的标题文字单击2.学生先学的基础单击此处添加您的标题文字单击此处添加您的标题文字单击3.学生的关注点 1999-2014 IX Web Hosting.All rights reserved“后茶馆式”教学!一种关注学生学习获得知识的方法过程，提高学生学习效能的教学方式教育指导 思想?陶行知:知识来源于实践。陶行知认识论：行（实践）知（知识）行（实践）教学 教法If not literally,at least to some extent!Try and get real t

14、ime reviews on your products/services.Ask questions about what your customers expect next and try to fit some of those suggestions into your work.This helps establish a rapport and shows you off as being customer driven.After all,this is exactly what people look for-to be heard!教学 过程 5分钟.合理安排，分解目标20

15、分钟.精确定位，明确目标18分钟.处方教学 2分钟.布置作业Producing a Variety of Content.9%No Answer.3%第一节课 合理安排，分解目标Dont always go for an all season look,get a makeover based on climate,festivities,etc;it gives a human touch to your business.A human business is more relatable than one that sounds also robotic and only sales o

16、riented.If overhauling the website every time isnt a feasible option;opt for changing the looks of your social profiles.For example,bring some variation in your cover pictures on Facebook if you feel like keeping the profile picture constant to your business logo.课前课上第一节课 合理安排，分解目标1 基本内容2 遵循原则3 使用方式

17、4 指导思想导学卡：现代心理学研究认为，合作学习是最佳的学习方式，学生在合作中交流，交流中形成合作的意识第一节课 合理安排，分解目标课堂随想：人们在生产生活当中所经历的典型的富有多种意义的事件陈述。第二节课 精确定位，明确目标案例分析：教学 过程.because in a world where we have access to unlimited information in a matter of seconds,information based marketing has become vital.一、案例关键点第二节课 精确定位，明确目标Its a social media too

18、l that not just focuses on presenting you with whats trending in your circles,but also helps you with CRM.It offers you insights on the popularity of your business 第二节课 精确定位，明确目标二、创设情景、导出难点设计意图：is by far the most popular tool in the market.No one has the time to go through text heavy posts;but who d

19、oesnt like bright images?Stock up on a lot of images that are unique to your business and fit them in your content strategy.They are the most shared post type across online platforms.第二节课 精确定位，明确目标三、教师师范，学生点评场景设计：教学反思有行动有感动有活动添加标题添加标题添加标题板书 设计一、高龄游客的特征Cutting edge technology at reasonable prices.tou

20、ch to your business.ScalabilityAbility to flex hosting plans in sync with the increasing needs of the website.二、导游人员的服务The 24/7 technical support is prompt and never lets your website down.SecurityCertified by the likes of McAfee,IX servers provide the most secure environment for hosting your web lo

21、gs.With The Most Shared Content Being.Heres Something Good To Know!60%of consumers enjoy reading relevant content from brands.82%of consumers feel more positive about a company after reading custom content.70%of consumers feel closer to a company as a result of content marketing.Gather Topics!Before

22、 you start creating your content plan and strategy,its always better to research and shortlist a handful of topics that are not just relevant to your business,but also trending in your circles.Talking about“whats in”helps you keep your audience hooked.Tell Your Story!People want to know the thought

23、process behind your business and how it came about to be.Share your story and your unique experiences along the way.It makes your business more relatable.SwayyIts a tool that analyzes your social community,matches the most relevant content from around the web and offers it on your dashboard,helps yo

24、u build a relationship between your content and your followers.SwayyRebelMouseClaimed as the front page of social media,helps you curate content for all your online profiles on a single dashboard based on what your business is known for and what conversations your audience has been engaging in.Rebel

25、Mouse谢谢大家教师说课PPT1 教材分析2 学情分析3 教学理念4 教学方法5 教学过程 教学反思More than 50%of your traffic comes from social media platforms.So how do you go about executing a content strategy AND keep track of whats trending?Here are a few tools to make the going easy教学重点教学难点高龄游客的特征如何灵活提供服务教学目标!Click here to add your text.Cl

26、ick here to add your text.Click here to add your text.知识目标01能力目标02情感目标03Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.Click here to add your text.学情 分析 单击此处添加您的标题文字单击此处添加您的标题文字单击1.学生原有的基础单击此处添加您的标题文字单击此处添加您

27、的标题文字单击2.学生先学的基础单击此处添加您的标题文字单击此处添加您的标题文字单击3.学生的关注点 1999-2014 IX Web Hosting.All rights reserved“后茶馆式”教学!一种关注学生学习获得知识的方法过程，提高学生学习效能的教学方式教育指导 思想?陶行知:知识来源于实践。陶行知认识论：行（实践）知（知识）行（实践）教学 教法If not literally,at least to some extent!Try and get real time reviews on your products/services.Ask questions about w

28、hat your customers expect next and try to fit some of those suggestions into your work.This helps establish a rapport and shows you off as being customer driven.After all,this is exactly what people look for-to be heard!教学 过程 5分钟.合理安排，分解目标20分钟.精确定位，明确目标18分钟.处方教学 2分钟.布置作业Producing a Variety of Conten

29、t.9%No Answer.3%第一节课 合理安排，分解目标Dont always go for an all season look,get a makeover based on climate,festivities,etc;it gives a human touch to your business.A human business is more relatable than one that sounds also robotic and only sales oriented.If overhauling the website every time isnt a feasib

30、le option;opt for changing the looks of your social profiles.For example,bring some variation in your cover pictures on Facebook if you feel like keeping the profile picture constant to your business logo.课前课上第一节课 合理安排，分解目标1 基本内容2 遵循原则3 使用方式4 指导思想导学卡：现代心理学研究认为，合作学习是最佳的学习方式，学生在合作中交流，交流中形成合作的意识第一节课 合理

31、安排，分解目标课堂随想：人们在生产生活当中所经历的典型的富有多种意义的事件陈述。第二节课 精确定位，明确目标案例分析：教学 过程.because in a world where we have access to unlimited information in a matter of seconds,information based marketing has become vital.一、案例关键点第二节课 精确定位，明确目标Its a social media tool that not just focuses on presenting you with whats trendi

32、ng in your circles,but also helps you with CRM.It offers you insights on the popularity of your business 第二节课 精确定位，明确目标二、创设情景、导出难点设计意图：is by far the most popular tool in the market.No one has the time to go through text heavy posts;but who doesnt like bright images?Stock up on a lot of images that a

33、re unique to your business and fit them in your content strategy.They are the most shared post type across online platforms.第二节课 精确定位，明确目标三、教师师范，学生点评场景设计：教学反思有行动有感动有活动添加标题添加标题添加标题板书 设计一、高龄游客的特征Cutting edge technology at reasonable prices.touch to your business.ScalabilityAbility to flex hosting plan

34、s in sync with the increasing needs of the website.二、导游人员的服务The 24/7 technical support is prompt and never lets your website down.SecurityCertified by the likes of McAfee,IX servers provide the most secure environment for hosting your web logs.With The Most Shared Content Being.Heres Something Good

35、To Know!60%of consumers enjoy reading relevant content from brands.82%of consumers feel more positive about a company after reading custom content.70%of consumers feel closer to a company as a result of content marketing.Gather Topics!Before you start creating your content plan and strategy,its alwa

36、ys better to research and shortlist a handful of topics that are not just relevant to your business,but also trending in your circles.Talking about“whats in”helps you keep your audience hooked.Tell Your Story!People want to know the thought process behind your business and how it came about to be.Sh

37、are your story and your unique experiences along the way.It makes your business more relatable.SwayyIts a tool that analyzes your social community,matches the most relevant content from around the web and offers it on your dashboard,helps you build a relationship between your content and your followers.SwayyRebelMouseClaimed as the front page of social media,helps you curate content for all your online profiles on a single dashboard based on what your business is known for and what conversations your audience has been engaging in.RebelMouse谢谢大家