Lesson 42 Recording and earthquake 记录地震
First listen and then answer the following question.
听录音,然后回答以下问题。
What does a pen have to do to record on paper the vibrations generated by an earthquake?
英式发音:
美式发音:
An earthquake comes like a thief in the night, without warning. It was necessary, therefore, to invent instruments that neither slumbered nor slept. Some devices were quite simple. One, for instance, consisted of rods of various lengths and thicknesses which would stand up on end like ninepins. When a shock came, it shook the rigid table upon which these stood. If it were gentle, only the more unstable rods fell. If it were severe, they all fell. Thus the rods, by falling, and by the direction in which they fell, recorded for the slumbering scientist the strength of a shock that was too weak to waken him, and the direction from which it came.
But instruments far more delicate than that were needed if any really serious advance was to be made. The ideal to be aimed at was to devise an instrument that could record with a pen on paper, the movements of the ground or of the table as the quake passed by. While I write my pen moves, but the paper keeps still. With practice, no doubt, I could in time learn to write by holding the pen still while the paper moved. That sounds a silly suggestion, but that was precisely the idea adopted in some of the early instruments (seismometers) for recording earthquake waves. But when table, penholder and paper are all moving, how is it possible to write legibly? The key to a solution of that problem lay in an everyday observation. Why does a person standing in a bus or train tend to fall when a sudden start is made? It is because his feet move on , but his head stays still. A simple experiment will help us a little further. Tie a heavy weight at the end of a long piece of string. With the hand held high in the air, hold the string so that the weight nearly touches the ground. Now move the hand to and fro and around but not up and down. It will be found that the weight moves but slightly or not at all. Imagine a pen attached to the weight in such a way that its point rests upon a piece of paper on the floor. Imagine an earthquake shock shaking the floor, the paper, you and your hand. In the midst of all this movement, the weight and the pen would be still. But as the paper moved from side to side under the pen point, its movement would be recorded in ink upon its surface. It was upon this principle that the first instruments were made, but the paper was wrapped round a drum which rotated slowly. As long as all was still, the pen drew a straight line, but while the drum was being shaken, the line that the pen was drawing wriggled from side to side. The apparatus thus described, however, records only the horizontal component of the wave movement, which is, in fact, much more complicated. If we could actually see the path described by a particle, such as a sand grain in the rock, it would be more like that of a bluebottle buzzing round the room; it would be up and down, to and fro and from side to side. Instruments have been devised and can be so placed that all three elements can be recorded in different graphs.
When the instrument is situated at more than 700 miles from the earthquake centre, the graphic record shows three waves arriving one after the other at short intervals. The first records the arrival of longitudinal vibrations. The second marks the arrival of transverse vibrations which travel more slowly and arrive several minutes after the first. These two have travelled through the earth. It was from the study of these that so much was learnt about the interior of the earth. The third, or main wave, is the slowest and has travelled round the earth through the surface rocks.
H.H,SWINNERTON The Earth beneath Us
The Shaw seismograph at the Science An earthquake recorded on a seismograph Museum,London
New words and expressions 生词与短语
earthquake n. 地震
slumber v. 睡眠
ninepin n. 九柱戏中的木柱
rigid adj. 坚硬的
delicate adj. 灵感的
seismometer n. 地震仪
penholder n. 笔杆
legibly adv. 字迹清楚地
drum n. 鼓状物
wriggle v. 扭动
bluebottle n. 绿头苍蝇
graph n. 图表
graphic adj. 图示的
longitudinal adj. 纵向的
transverse adj. 横向的
Notes on the text 课文注释
1、stand up on end,竖立着。
2、the ideal to be aimed at,理想的目标。
3、I could in time...,我最终能够....。
4、help us a little further,帮助我们进一步搞清这个问题。
5、with the hand...hold the string...,这是一个祈使句,谓语动词是hold,with the hand held high in the air是介词短语作方式状语。
6、to and fro,来回地。
参考译文
地震就像夜间的小偷,不打招呼就来了。因此,有必要发明一种仪器,既不打盹儿,也不睡觉。有些装置非常简单。例如,有一种装置是由一些长短、粗细不同的木棒组成,就像九柱戏的木棒一样坚立着,一旦有地震,就会震动竖立在坚硬的桌上的木棒。如果地震轻微,只有不稳定的木棒倒下;如果地震剧烈,所有的木棒都会例下。由于地震太弱而未惊醒科学家时,木棒倒下的多少和倒下的方向就为科学家记录下了地震的强度和地震方向。
但是,如果要取得真正重大的进展,需要有比这种装置精细得多的仪器。理想的目标是设计出这样一种仪器:当地震发生时,它能用笔在纸上记录下大地和桌子运动情况。我写字时,笔是移动的,纸是静止的。毫无疑问,经过练习,我最终能够学会笔不动而纸动来写字。这听起来似乎是一种愚蠢的想法,但是早期记录地震波的仪器(地震仪)正是采用了这中思路。可是,当桌子、夹笔装置、纸都在移动时,怎么能书写得清楚呢?可以从我们的日常生活观察中找到这个问题的答案。一个站在公共汽车或火车上,当车突然开动时,他为什么会倾倒呢?这是因为他的脚动了,而他的头保持着静止。再做一个简单的实验可以帮助我们进一步理解这个问题。把一个生物拴在一根长绳子的一端,把手高高举在空中握住绳子,让重物几乎接触地面。然后把手前后左右以及旋转摆动,但不要上下摆动。结果会发现,重物是动了,但动得很小,甚至没动。假定把一支笔拴在重物上,笔尖落在地板上的一张纸上,假定地震发生了,地板、纸、你和你的手都会动,重物和笔却不动。由于纸在笔下来回运动,纸的表面就会用墨水记录下地板运动的情况。根据这一原理,制造出了最初的地震仪器,但是纸是卷在慢慢放置的圆筒上的。只要一切都是静止的,笔就会划出一条直线;但是,圆筒受到震动,笔所画出的线就会就会左右摆动。然而,这里所说的仪器记录下来的只是地震波运动中的水平部份,地震波的运动实际比这要复杂得多。假如我们真能看到诸如岩石中一个沙粒子的运动轨迹,那就像一只嗡嗡叫的绿头苍蝇在屋内飞行的轨迹,呈现出上上下下、来来回回、左左右右3种性质的运动。已经设计出了一些仪器,它按照一定的安放方式就可测绘出这三种运动的曲线图。
如果把这种仪器安装在距震源700多英里远的地方,曲线记录就能显示出前后相同的这3种地震波。首先记录下的是纵向波的到达;然后记录下的是横向波的到达,横向波比纵向波传播得慢,在纵向波到过几分钟后能到达。这珍两种波都是穿过地球而来的。正是从这两种波中的研究中,我们可以了解到地球内部的许多情况。第三种波,即主波,是最慢的,是围绕地球通过表面岩石传来的。
推荐专题:
本文地址:http://nce.haohaoxue.com/NCE4/2020-12-09/361253.html
- 节日作文
- 植树节作文
- 妇女节作文
- 国庆节作文
- 元宵节作文
- 六一儿童节作文
- 端午节作文
- 五一劳动节作文
- 清明节作文
- 五四青年节作文
- 父亲节作文
- 重阳节作文
- 元旦作文
- 建军节作文
- 中秋节作文
- 母亲节作文
- 教师节作文
- 圣诞节作文
- 愚人节作文
- 万圣节作文
- 励志作文
- 奥运会作文
- 理想作文
- 中国梦作文
- 自信作文
- 青春作文
- 挫折作文
- 成长作文
- 坚持作文
- 宽容作文
- 诚信作文
- 坚强作文
- 情感作文
- 感恩作文
- 抒情作文
- 感动的作文
- 搞笑作文
- 微笑作文
- 孝心作文
- 母爱作文
- 幸福作文
- 父爱作文
- 爱的作文
- 人物作文
- 我的妈妈作文
- 我的爸爸作文
- 母亲作文
- 父亲作文
- 我的老师作文
- 我的同学作文
- 我的叔叔作文
- 外婆作文
- 朋友作文
- 班主任作文
- 偶像作文
- 我作文
- 小伙伴作文
- 鲁迅作文
- 雷锋作文
- 清洁工作文
- 自然作文
- 春天来了作文
- 下雪了作文
- 台风作文
- 秋天作文
- 夏天作文
- 黄山作文
- 流星雨作文
- 黄河作文
- 大海作文
- 下雨作文
- 冬天作文
- 泰山作文
- 动物作文
- 小狗作文
- 小猫作文
- 熊猫作文
- 鹦鹉作文
- 蝴蝶作文
- 大象作文
- 蛇的作文
- 燕子作文
- 猴子作文
- 蚂蚁作文
- 老虎作文
- 金鱼作文
- 兔子作文
- 乌龟作文
- 马的作文
- 植物作文
- 西瓜作文
- 仙人掌作文
- 兰花作文
- 荷花作文
- 梅花作文
- 苹果作文
- 菊花作文
- 竹子作文
- 树叶作文
- 油菜花
- 柳树作文
- 葡萄作文
- 吊兰作文
- 牡丹作文
- 树的作文
- 生活作文
- 游记作文
- 环保作文
- 小制作作文
- 寒假作文
- 我的课余生活作文
- 童年趣事作文
- 游戏作文
- 第一次作文
- 春游作文
- 踏青作文
- 军训作文
- 音乐作文
- 暑假作文
- 春节作文
- 春节英语作文
- 压岁钱作文
- 除夕夜作文
- 写作素材
- 倡议书
- 感谢信
- 检讨书
- 发言稿
- 演讲稿
- 国旗下讲话
- 导游词
- 应 用 文
- 高考作文素材
- 高中作文素材
- 中考作文素材
- 初中作文素材
- 名言警句
- 历史典故
- 名人故事
- 优秀句段
- 哲理故事
- 成语故事
- 名著读后感
- 红楼梦读后感
- 三国演义读后感
- 水浒传读后感
- 西游记读后感
- 詹天佑读后感
- 夏洛的网读后感
- 鲁滨孙漂流记读后感
- 窗边的小豆豆读后感
- 伊索寓言读后感
- 巴黎圣母院读后感
- 高老头读后感
- 青铜葵花读后感
- 城南旧事读后感
- 绿山墙的安妮读后感
- 骆驼祥子读后感
- 会飞的教室读后感
- 爱的教育读后感
- 钢铁是怎样炼成的读后感
- 草房子读后感
- 教师读后感
- 格列佛游记读后感
- 昆虫记读后感
- 朝花夕拾读后感
- 雷锋读后感
- 傅雷家书读后感
- 海底两万里读后感
- 童年读后感
- 老人与海读后感
- 简爱读后感
- 名人传读后感
- 平凡的世界读后感
- 繁星春水读后感
- 百年孤独读后感
- 八十天环游地球读后感
- 卖火柴的小女孩读后感
- 安徒生童话读后感
- 假如给我三天光明读后感
- 傲慢与偏见读后感
- 大卫科波菲尔读后感
- 汤姆索亚历险记读后感
- 悲惨世界读后感
- 英语作文
- 一年级英语作文
- 二年级英语作文
- 三年级英语作文
- 四年级英语作文
- 五年级英语作文
- 六年级英语作文
- 初一英语作文
- 初二英语作文
- 初三英语作文
- 高一英语作文
- 高二英语作文
- 高三英语作文
- 英语四级作文
- 英语六级作文
- 考研英语作文
- 高考英语作文
- 中考英语作文