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70楼#
发布于：2013-10-13 14:02
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71楼#
发布于：2013-10-13 14:03
初中物理知识记忆“顺口溜” 
一、声学 物因振动而发声，振动停止停发声。固比液气传声快，真空不能传播声。 感知声音两途径，双耳效应方向明。规则振动叫乐音，无规振动生噪声。 分贝强弱要注意，乐音也能变噪声。防噪产生阻传声，严防噪声入耳中。 声音大小叫响度，响度大小看振幅。距离太远响度小，减少分散增大声。 声音高低叫音调，频率高低调不同，长松粗低短紧高，发声物体要看清。 同一音调乐器多，想要区分靠音色，只闻其声知其人，音色不同传信息。 超声次声听不到，回声测距定位妙。B超查病信息传，超声碎石声传能。 二、光学 发光物体叫光源，描述路径有光线。直线传播有条件，同种介质需均匀。 影子小孔日月食，还有激光能准直。向右看齐听口令，三点一线能命中。 月亮本不是光源，长度单位有光年。传光最快数真空，8分能飞到月宫。 光线原以直线过，遇到界面成反射。一面两角和三线，法线老是在中间。 三线本来就共面，两角又以相等见。入射角变反射角，光路可逆互相看。 反射类型有两种，成像反射靠镜面。学生坐在各角落，看完全凭漫反射。 若是个别有"反光"，那是镜面帮倒忙。 镜面反射成虚像，像物同大都一样。物远像远没影响，连线垂直镜中央。 还有凸面凹面镜，反光作用不一样。凹面镜能会聚光，来把灯碗灶台当。 观后镜使光发散，扩大视野任车转。 不管凸透凹透镜，都有一定折射性。经过光心不变向，会聚发散要分清。 平行光束穿透镜，通过焦点是一定。折射光线可逆行，焦点出发必平行。 显微镜来是组合，两个镜片无分别。只是大小不一样，焦距位置要适当。 物镜实像且放大，目镜虚像再放大。望远镜来看得清，全靠两片凸透镜。 物镜实像来缩小，目镜虚像又放大。为啥感觉像变大，全靠视角来变化。 画反射光路图： 作图首先画法线，反入夹角平分线，垂直法线立界面。光线方向要标全。 画折射光路： 空射水玻折向法，水玻射空偏离法。海市蜃楼是折射，观察虚像位偏高。 凸透镜成像： 一倍焦距不成像，内虚外实分解明。二倍焦距物像等，外小内大实像成。 物近像远像变大，物远像近像变小。实像倒立虚像正，照、投、放大对应明。 眼睛和眼镜： 晶薄焦长看远物，晶厚焦短看近物。晶厚近视薄远视，凹透矫近凸矫远。 近物光聚网膜前，已经成为近视眼。远物光聚网膜后，已经成为老花眼。 三、热学 冷热表示用温度，热胀冷缩测温度。冰点零度沸点百，常用单位摄氏度。 量程分度要看好，放对观察视线平。测体温前必先甩，细缩口和放大镜。 物体状态有三类，固体液体和气体。物态变化有六种，熔凝汽液升凝华。 汽化当中有不同，既有蒸发又沸腾。蒸发快慢不相同，温度面积其流通。 液化方法有区分，压缩体积和降温。液化现象遍天地，雨雾露水和白气。 升华现象不一般，灯丝变细冻衣干。凝华现象造图画，窗花霜雪和树挂。 晶体熔化和凝固，吸放热但温不变，液体沸腾需吸热，升到沸点温不变。 人工降雨本领大，干冰升华又液化。吸收热量能制冷，熔化升华和汽化。 四、电路及特点： 摩擦起电本领大，电子转移有变化。吸引排斥验电器，静电放电要注意。 毛皮摩擦橡胶棒，棒上负电比较强。丝绸摩擦玻璃棒，丝负玻正等电量。 定向移动成电流，电流方向有规定。电源外部正到负，自由电子是倒流。 容易导电是导体，不易导电是绝缘。绝缘自由电荷少，防止漏电和触电。 学电路前画元件，认真规范是关键。整个图形是长框，元件均匀摆四方。 拐弯之处留空白，这样标准显出来。通路断路和短路，最后一路烧电源。 基本电路串并联，分清特点是关键。串联就是一条路，正极出发负极回。 一灯烧毁全路断，一个开关管全局。开关位置无影响，局部短路特殊用。 并联电流像河流，分了干路分支流。干路开关全控制，支路电器独立行。 串联等流电压分，并联分流电压等。串联灯亮电阻大，并联灯亮小电阻。 照明电路和安全用电 火线零线要分清，示意图上总平行。电度表来测电能，保险丝在干路中。 各种插座要并联，用电器间也包含。灯泡开关是串联，开关接的是火线。 尾部金属接火线，这样来做最安全。零线要接螺旋套，预防触电要牢记。 金属外壳用电器，中间插脚要接地。三孔插座用两孔，绝缘破损太危险。 功率过大会超载，电路短路更危险。保险装置起作用，电表铭牌会计算。 安全电压要牢记，构成通路会触电。高压带电不靠近，触电首先断电源。 树下避雨要当心，高物要装避雷针。湿手莫要扳开关，老化元件勤更换。 六、伏安法测电阻，电功率连接电路 画电路，连元件，连线过程断开关，滑片移到最大端，电压表并，电流表串。 “正”“负”接错针反，整理仪器再计算。 “同段导体三个量，I,U正比I，R反，不管I，U多变换，理解R是不变。W=UIt，可用谐音法记作：大不了，又挨踢。” 七、电与磁 （1）、磁体周围有磁场，北出南回磁感向，场外北极也一样。 （2）、闭导切割磁感线，感应电流就出现。改变动向流向变，机械能向电能转。 电磁感应来发电，法拉第贡献不一般。 （3）、判断螺线用安培，右手紧握螺线管。电流方向四指所指，N极指向拇指端。 初三 五、力学 1、正确使用刻度尺的“四要” 尺子要放正，视线要垂直，读数要估计，记录要单位。 测量仪器要读书，最小刻度要记住。天平游码看左边，量筒水面看底部。 压强记读高度差，上小下大密度计。电流电压先看档，电能表上有小数。 2,质量与密度 质量本是一属性，物体本身来决定。状态、形状和位置，外变不变其大小。 一放平，二调零，三调横梁成水平，指针偏哪哪边重，螺母反向高处动，以及 “称物体，先估计，左物右码方便自己；夹砝码须心细，加减对应盘高低”。 密度一般是一定，温度变化会不同，体积换算勿遗忘，立方厘米对毫升。 3、机械运动 运动和静止，贵在选参照，快慢和方向，相同是静止。 “物体有惯性，惯性是属性，大小看质量，不论动与静。” 4、平均速度的计算 运动路线示意图，运动问题更分明。过桥穿洞要记清，桥长车长为路程。 相遇、追击有诀窍，找好路程列方程。回声激光来测距，距离两倍是路程。 5、二力平衡的条件 一物二力能平衡，方向相反大小等。一条直线是条件，合力一定等于零。 6、力的图示的步骤 一画简图二定点，三定标度四画线，五截线段六画尖，最后数据标尖边。 7、二力合成的特点 二力合成一条直线。同向相加反向减，同向方向不改变，反向随着大的变。 8、力臂的确定及其画法 找支点，画力线（力的作用），从点（支点）向线（力的作用线）引垂线， 力臂就是此线段。 9、连通器的特点 连通器，底连通，同液体，同高低。 10、液体内部的压强 液内各方有压强，无论对底或壁上，同深各向等压强，密度深度有影响。 不能忘----密度gh相乘在一堂。 11、阿基米德原理 液物向上向下压力差，浮力大小就是它。浮力重力向上爬，重力浮力深处下。 两力相等悬漂啦。要问浮力有多大？密度gv排计算它。 |
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72楼#
发布于：2013-10-13 14:09
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73楼#
发布于：2013-10-13 14:10
英语中常见的123个中国成语
1.爱屋及乌 Love me, love my dog. 2.百闻不如一见 Seeing is believing. 3.比上不足比下有余 worse off than some, better off than many; to fall short of the best, but be better than the worst. 4.笨鸟先飞 A slow sparrow should make an early start. 5.不眠之夜 white night 6.不以物喜不以己悲 not pleased by external gains, not saddened by personnal losses 7.不遗余力 spare no effort; go all out; do one's best 8.不打不成交 No discord, no concord. 9.拆东墙补西墙 rob Peter to pay Paul 10.辞旧迎新 bid farewell to the old and usher in the new; ring out the old year and ring in the new 11.大事化小小事化了 try first to make their mistake sound less serious and then to reduce it to nothing at all 12.大开眼界 open one's eyes; broaden one's horizon; be an eye-opener 13.国泰民安 The country flourishes and people live in peace 14.过犹不及 going too far is as bad as not going far enough; beyond is as wrong as falling short; too much is as bad as too little 15.功夫不负有心人 Everything comes to him who waits. 16.好了伤疤忘了疼 once on shore, one prays no more 17.好事不出门恶事传千里 Good news never goes beyond the gate, while bad news spread far and wide. 18.和气生财 Harmony brings wealth. 19.活到老学到老 One is never too old to learn. 20.既往不咎 let bygones be bygones 21.金无足赤人无完人 Gold can't be pure and man can't be perfect. 22.金玉满堂 Treasures fill the home. 23.脚踏实地 be down-to-earth 24.脚踩两只船 sit on the fence 25.君子之交淡如水 the friendship between gentlemen is as pure as crystal; a hedge between keeps friendship green 26.老生常谈陈词滥调 cut and dried, cliché 27.礼尚往来 Courtesy calls for reciprocity. 28.留得青山在不怕没柴烧 Where there is life, there is hope. 29.马到成功 achieve immediate victory; win instant success 30.名利双收 gain in both fame and wealth 31.茅塞顿开 be suddenly enlightened 32.没有规矩不成方圆 Nothing can be accomplished without norms or standards. 33.每逢佳节倍思亲 On festive occasions more than ever one thinks of one's dear ones far away.It is on the festival occasions when one misses his dear most. 34.谋事在人成事在天 The planning lies with man, the outcome with Heaven. Man proposes, God disposes. 35.弄巧成拙 be too smart by half; Cunning outwits itself 36.拿手好戏 masterpiece 37.赔了夫人又折兵 throw good money after bad 38.抛砖引玉 a modest spur to induce others to come forward with valuable contributions; throw a sprat to catch a whale 39.破釜沉舟 cut off all means of retreat；burn one‘s own way of retreat and be determined to fight to the end 40.抢得先机 take the preemptive opportunities 41.巧妇难为无米之炊 If you have no hand you can't make a fist. One can't make bricks without straw. 42.千里之行始于足下 a thousand-li journey begins with the first step--the highest eminence is to be gained step by step 43.前事不忘后事之师 Past experience, if not forgotten, is a guide for the future. 44.前人栽树后人乘凉 One generation plants the trees in whose shade another generation rests.One sows and another reaps. 45.前怕狼后怕虎 fear the wolf in front and the tiger behind hesitate in doing something 46.强龙难压地头蛇 Even a dragon (from the outside) finds it hard to control a snake in its old haunt - Powerful outsiders can hardly afford to neglect local bullies. 47.强强联手 win-win co-operation 48.瑞雪兆丰年 A timely snow promises a good harvest. 49.人之初性本善 Man's nature at birth is good. 50.人逢喜事精神爽 Joy puts heart into a man. 51.人海战术 huge-crowd strategy 52.世上无难事只要肯攀登 Where there is a will, there is a way. 53.世外桃源 a fictitious land of peace away from the turmoil of the world; 54.死而后已 until my heart stops beating 55.岁岁平安 Peace all year round. 56.上有天堂下有苏杭 Just as there is paradise in heaven, ther are Suzhou and Hangzhou on earth 57.塞翁失马焉知非福 Misfortune may be an actual blessing. 58.三十而立 A man should be independent at the age of thirty.At thirty, a man should be able to think for himself. 59.升级换代 updating and upgrading (of products)60.四十不惑 Life begins at forty. 61.谁言寸草心报得三春晖 Such kindness of warm sun, can't be repaid by grass. 62.水涨船高 When the river rises, the boat floats high. 63.时不我待Time and tide wait for no man. 64.杀鸡用牛刀break a butterfly on the wheel 65.实事求是seek truth from facts; be practical and realistic; be true to facts 66.说曹操,曹操到Talk of the devil and he comes. 67.实话实说speak the plain truth; call a spade a spade; tell it as it is 68.实践是检验真理的唯一标准Practice is the sole criterion for testing truth. 69.山不在高，有仙则名'No matter how high the mountain is, its name will spread far and wide if there is a fairy; ' 70.韬光养晦hide one's capacities and bide one's time 71.糖衣炮弹sugar-coated bullets 72.天有不测风云Anything unexpected may happen. a bolt from the blue 73.团结就是力量Unity is strength. 74.“跳进黄河洗不清”'eve if one jumped into the Yellow River, one can not wash oneself clean--there's nothing one can do to clear one's name ' 75.歪风邪气unhealthy practices and evil phenomena 76.物以类聚，人以群分Birds of a feather flock together. 77.往事如风'The past has vanished (from memory) like wind.; What in past, is pas 78.望子成龙hold high hopes for one's child 79.屋漏又逢连阴雨Misfortunes never come singly. When it rains it pours. 80.文韬武略military expertise; military strategy 81.唯利是图draw water to one's mill 82.无源之水,无本之木water without a source, and a tree wiithout roots 83.无中生有make create something out of nothing 84.无风不起浪There are no waves without wind. There's no smoke without fire. 85.徇私枉法bend the law for the benefit of relatives or friends 86.新官上任三把火a new broom sweeps clean 87.虚心使人进步,骄傲使人落后Modesty helps one go forward, whereas conceit makes one lag behind. 88. 蓄势而发accumulate strength for a take-off 89.心想事成May all your wish come true 90.心照不宣have a tacit understanding; give tacit consent; tacit understanding 91.先入为主First impressions are firmly entrenched. 92.先下手为强catch the ball before the bound 93.像热锅上的蚂蚁like an ant on a hot pan 94.现身说法warn people by taking oneself as an example 95.息事宁人pour oil on troubled waters 96.喜忧参半mingled hope and fear 97.循序渐进step by step 98.一路平安，一路顺风speed somebody on their way; speed the parting guest 99.严以律己,宽以待人be strict with oneself and lenient towards others 100鱼米之乡101.有情人终成眷属'Jack shall have Jill, all shall be well.' 102.有钱能使鬼推磨Money makes the mare go. Money talks. 103. 有识之士people of vision 104.有勇无谋use brawn rather than brain 105.有缘千里来相会Separated as we are thousands of miles apart, we come together as if by predestination. 106.与时俱进advance with times 107.以人为本people oriented; people foremost 108.因材施教teach students according to their aptitude 109.欲穷千里目，更上一层楼'to ascend another storey to see a thousand miles further; Ascend further, were you to look farther; Would eye embrace a thousand miles? Go up, one flight.' a land of milk and honey 110.欲速则不达Haste does not bring success. 111. 优胜劣汰survival of the fittest 112.英雄所见略同Great minds think alike. 113.冤家宜解不宜结Better make friends than make enemies. 114.冤假错案'cases in which people were unjustly, falsely or wrongly charged or sentenced; unjust, false or wrong cases' 115.一言既出，驷马难追A real man never goes back on his words. 116.招财进宝Money and treasures will be plentiful 117.债台高筑become debt-ridden 118.致命要害Achilles' heel 119. 众矢之的target of public criticism 120.知己知彼,百战不殆Know the enemy and know yourself, and you can fight a hundred battles with no danger of defeat. 121. 纸上谈兵be an armchair strategist 122.纸包不住火Truth will come to light sooner or later. 123.左右为难between the devil and the deep blue sea |
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74楼#
发布于：2013-10-13 14:12
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75楼#
发布于：2013-10-13 14:16
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76楼#
发布于：2013-10-13 14:23
，，禁回复
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77楼#
发布于：2013-10-13 14:35
化学动态教学课件
不看别后悔 只有老师才有的【我舅舅是化学老师】 这是金榜的教学课件 |
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78楼#
发布于：2013-10-13 14:39
化学动态教学课件 2
我会一单元一单元的上传的 |
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79楼#
发布于：2013-10-13 14:42
化学动态教学课件 3
这周先上传前三个单元 剩下的下周再发 禁回帖 |
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