我国初级阶段的基本国情-人人终身学习知识网~是各类综合知识资源信息分享，提升综合素质与提高知识技能的终身学习网络平台政治教学政治

meili 发表于 2022-10-21 14:13:06

我国初级阶段的基本国情

初中物理教案<?xml:namespace prefix =v ns ="urn:schemas-microsoft-com:vml" /><v:line id=_x2023_s2023 style="Z-INDEX: 60; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,15.55pt" from="0,15.55pt"></v:line> 课题怎样认识力<v:line id=_x2023_s2023 style="Z-INDEX: 59; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,6.75pt" from="0,6.75pt"></v:line> 教学目的1、理解力是一个物体对另一个物体的作用，能分析简单情况下的受力物体和施力物体。2、知道物体间力的作用是相互的。3、知道力可以改变物体的运动状态，知道力可以引起物体的形变。4、知道力的单位：牛（N）。<v:line id=_x2023_s2023 style="Z-INDEX: 57; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="63pt,272.35pt" from="63pt,14.95pt"></v:line>5、培养学生的观察能力和分析概括能力。<v:line id=_x2023_s2023 style="Z-INDEX: 61; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,10.55pt" from="0,10.55pt"></v:line> 重、难点力的概念（重点）力的概念及单位，物体间力的作用是相互的。（难点）<v:line id=_x2023_s2023 style="Z-INDEX: 62; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,12.95pt" from="0,12.95pt"></v:line> 教具弹簧、钩码、小球、磁铁（两块）、小车（两辆）、铁钉、碎纸屑、丝绸、玻璃棒；多媒体计算机及大屏幕投影整套设备、辅助教学光盘等。<v:line id=_x2023_s2023 style="Z-INDEX: 63; 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POSITION: absolute; TEXT-ALIGN: left" to="63pt,324.15pt" from="63pt,-3.45pt"></v:line> 新课教学：一、力是什么？（多媒体投影）1、观察、演示：① 观察实验：钩码挂在弹簧下出现的情况；② 观看课本P87熊猫攀吊竹枝的图片；③ 观察实验：用玻璃棒击小球的情况；④多媒体投影：钩码挂在弹簧下的情况、棒击小球时的情况以及足球运动员头顶球时的动画。2、带领学生记录并分析①②情况、③④实验及投影的情况如下：<v:rect id=_x2023_s2023 style="MARGIN-TOP: -0.05pt; Z-INDEX: 7; LEFT: 0px; MARGIN-LEFT: 387pt; WIDTH: 1in; POSITION: absolute; HEIGHT: 39pt; TEXT-ALIGN: left"></v:rect><TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD style="BORDER-RIGHT: #ece9d8; BORDER-TOP: #ece9d8; BORDER-LEFT: #ece9d8; BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent">物体发生了形变</TR></TABLE><v:line id=_x2023_s2023 style="Z-INDEX: 5; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="378pt,23.35pt" from="5in,7.75pt"><v:stroke endarrow="block"></v:stroke></v:line><v:rect id=_x2023_s2023 style="MARGIN-TOP: -0.05pt; Z-INDEX: 4; LEFT: 0px; MARGIN-LEFT: 243pt; WIDTH: 45pt; POSITION: absolute; HEIGHT: 78pt; TEXT-ALIGN: left"></v:rect><TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD style="BORDER-RIGHT: #ece9d8; 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LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="270pt,17.15pt" from="198pt,17.15pt"><v:stroke endarrow="block"></v:stroke></v:line>拍<v:line id=_x2023_s2023 style="Z-INDEX: 43; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left; flip: x" to="270pt,4.95pt" from="198pt,4.95pt"><v:stroke endarrow="block"></v:stroke></v:line>拍5、概括：① 先请学生回答：上面的实例、实验、投影说明了什么？<v:rect id=_x2023_s2023 style="MARGIN-TOP: 2.35pt; Z-INDEX: 44; LEFT: 0px; MARGIN-LEFT: 2in; WIDTH: 63pt; POSITION: absolute; HEIGHT: 70.2pt; TEXT-ALIGN: left"></v:rect><TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD style="BORDER-RIGHT: #ece9d8; BORDER-TOP: #ece9d8; BORDER-LEFT: #ece9d8; BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent">施力物体受力物体</TR></TABLE><v:rect id=_x2023_s2023 style="MARGIN-TOP: 2.35pt; Z-INDEX: -32; LEFT: 0px; MARGIN-LEFT: 4in; WIDTH: 63pt; POSITION: absolute; HEIGHT: 70.2pt; TEXT-ALIGN: left"></v:rect><TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD style="BORDER-RIGHT: #ece9d8; 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BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent">甲</TR></TABLE></v:textbox></v:oval><v:oval id=_x2023_s2023 style="MARGIN-TOP: 3.55pt; Z-INDEX: 75; LEFT: 0px; MARGIN-LEFT: 162pt; WIDTH: 36pt; POSITION: absolute; HEIGHT: 31.2pt; TEXT-ALIGN: left"><v:textbox><TABLE cellSpacing=0 cellPadding=0 width="100%"><TBODY><TR><TD style="BORDER-RIGHT: #ece9d8; BORDER-TOP: #ece9d8; BORDER-LEFT: #ece9d8; BORDER-BOTTOM: #ece9d8; BACKGROUND-COLOR: transparent">甲</TR></TABLE></v:textbox></v:oval> <v:line id=_x2023_s2023 style="Z-INDEX: 47; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left; flip: x" to="4in,6.75pt" from="207pt,6.75pt"><v:stroke endarrow="block"></v:stroke></v:line>F2② 教师总结（结论）：物体间力的作用是相互的。（多媒体投影）③ 指导学生填好教材P89方框中的空格。5、教师讲解：研究力的时候，必须明确谁施力，谁受力。在<v:line id=_x2023_s2023 style="Z-INDEX: 55; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="63pt,543.15pt" from="63pt,4.35pt"></v:line> 上述实验和投影中对于人:甲推乙的力来说，甲施力，乙受力；而对乙推甲的力来说,乙施力,甲受力，是同时发生的。a. 对于磁铁：甲吸引乙的力来说，甲施力，乙受力；而对乙吸引甲的力来说，乙施力，甲受力，同时发生。对于同名磁极相斥，也具有同样道理。6、问题：人游泳时用手和脚向后划水，人就能前进，这是为什么？（提问学生后多媒体投影）7、想一想：①多媒体投影：足球运动员踢球、顶球、接球时的动画。② 请学生回答：足球运动员在踢球、头顶球、守门员接球时施力情况、受力情况如何？足球的运动状态在甲、乙、丙三个运动员处相应发生了哪些变化？三、<v:line id=_x2023_s2023 style="Z-INDEX: 54; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left; flip: x" to="63pt,337.55pt" from="63pt,14.35pt"></v:line>力的单位长期以来，力的单位有多种，很不统一，如：斤、磅、公斤、千克力等等，这样不利于各国间的文化科技的交流，直到2023年国际计量大会后才趋于统一。1、在国际单位制中，力的单位是：牛顿，简称：牛，符号：N.——为纪念英国著名科学家牛顿而命名的。那么1牛的力到底有多大呢？看：大屏幕投影2、人手托起两个鸡蛋的力大约是1牛（请同学们回去后实际做一做，一个鸡蛋的质量大约是50克）。3、手托物理课本的力大约是3牛。（同学们亲自体验一下）4、下面几个物体（蚂蚁、大型拖拉机、长征系列运载火箭）的拉力或推力，请同学们看多媒体投影。<v:line id=_x2023_s2023 style="Z-INDEX: 73; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="63pt,737.55pt" from="63pt,-3.45pt"></v:line><v:line id=_x2023_s2023 style="Z-INDEX: 72; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="135pt,737.55pt" from="135pt,-3.45pt"></v:line>巩固小结1、力是物体对物体的作用，力不能离开物体而单独存在；物体间发生力的作用时，一定有施力物体和受力物体。直接接触的物体间可以发生力的作用，不直接接触的物体间也能发生力的作用。<v:line id=_x2023_s2023 style="Z-INDEX: 52; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left; flip: y" to="306pt,28.55pt" from="4in,12.95pt"><v:stroke endarrow="block"></v:stroke></v:line>力可以是物体发生形变2、<v:line id=_x2023_s2023 style="Z-INDEX: 53; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="306pt,31.95pt" from="4in,16.35pt"><v:stroke endarrow="block"></v:stroke></v:line>力的作用效果力可以使物体的运动状态发生改变3、物体间力的作用是相互的，能运用这个知识解释生活、生产实际中遇到的一些实例。4、在国际单位制中，力的单位是：牛（顿）-N托起两个鸡蛋的力大约是1N。<v:line id=_x2023_s2023 style="Z-INDEX: 56; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,8.35pt" from="63pt,8.35pt"></v:line> 课堂讨论物理课本P90作业 2、3<v:line id=_x2023_s2023 style="Z-INDEX: 74; LEFT: 0px; POSITION: absolute; TEXT-ALIGN: left" to="459pt,16.35pt" from="63pt,16.35pt"></v:line> 作业处理1、认真复习课本和指导书中本节内容，预习下节知识《怎样表示力》。2、书面作业：课本 P90作业 1、4指导书 P58练习 4、5、6

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