新概念英語(yǔ)第四冊(cè)Lesson+42+Recording+an+earthquake+講義

Lesson42Recording1anearthquake記錄地震Whatdoesapenhavetodotorecordonpaperthevibrations2generatedbyanearthquake?Anearthquakecomeslikeathiefinthenight,withoutwarning.Itwasnecessary,therefore,toinventinstrumentsthatneitherslumbered4norslept.Somedeviceswerequitesimple.One,forinstance,consistedofrodsofvariouslengthsandthicknesseswithwouldstandupendlikeninepins.Whenashockcame,itshooktherigid5tableuponwhichthesestood.Ifitweregentle,onlythemoreunstable6rodsfell.Ifitweresevere,theyallfell.Thustherods,byfalling,andbythedirectioninwhichtheyfell,recordedforthesevere,theyallfell.Thustherods,byfalling,andbythedirectioninwhichtheyfell,recordedfortheslumbering7scientistthestrengthofashockthatwastooweaktowakenhim,andthedirectionfromwhichitcame.Butinstrumentsfarmoredelicatethanthatwereneededifanyreallyseriousadvancewastobemade.Theidealtobeaimedatwastodeviseaninstrumentthatcouldrecordwithapenonpaper,themovementsofthegroundorofthetableasthequakepassedby.WhileIwritemypenmoves,butthepaperkeepsstill.Withpractice,nodoubt,Icouldintimelearntowritebyholdingthepenstillwhilethepapermoved.Thatsoundsasillysuggestion,butthatwasprecisely8theideaadoptedinsomeoftheearlyinstruments(seismometers)forrecordingearthquakewaves.Butwhentable,penholderandpaperareallmoving,howisitpossibletowritelegibly?Thekeytoasolutionofthatproblemlayinaneverydayobservation.Whydoesapersonstanding9inabusortraintendtofallwhenasuddenstartismade?Itisbecausehisfeetmoveon,buthisheadstaysstill.Asimpleexperimentwillhelpusalittlefurther.Tieaheavyweightattheendofalongpieceofstring.Withthehandtoandfroandaroundbutnotupandstringsothattheweightnearlytouchestheground.Nowmovethehandtoandfroandaroundbutnotupanddown.Itwillbefoundthattheweightapieceofstring.Withthehandheldhighintheair,holdthestringsothattheweightnearlytouchestheground.Nowmovethehandtoandfroandaroundbutnotupanddown.Itwillbefoundthattenweightmovesbutslightlyornotatall.Imagineanearthquakeshockshakingthefloor,thepaper,youandyourhand.Inthemidstofallthismovement,theweightandthepenwouldbestill.Butasthepapermovedfromsidetosideunderthepenpoint,itsmovementwouldberecordedininkuponitssurface.Itwasuponthisprinciplethatthefirstinstrumentsweremade,butwhilethedrumwasbeingshaken,thelinethatthepenwasdrawingwriggled11fromsidetoside.Theapparatus12thusdescribed,however,recordsonlythehorizontalcomponent13ofthewavemovement,whichis,infact,muchmorecomplicated.Ifwecouldactuallyseethepathdescribedbyaparticle,suchasasandgrainintherock,itwouldbemorelikethatofabluebottlepathdescribedbyaparticle,suchasasandgrainintherock,itwouldbemorelikethatofabluebottlebuzzingroundtheroom;itwouldbeupanddown,toandfroandfromsidetoside.Instrumentshavebeendevisedandcanbesoplacedthatallthreeelementscanberecordedindifferentgraphs.Whentheinstrumentissituated14atmorethan700milesfromtheearthquakecentre,thegraphic15recordshowsthreewavesarrivingoneafteratshortintervals16.Thefirstrecordsthearrivaloflongitudinalvibrations.Thesecondmarksthearrivaloftransversevibrationswhichtravelmoreslowlyandarriveseveralminutesafterthefirst.Thesetwohavetravelledthroughtheearth.Itwasfromthestudyofthesethatsomuchwaslearntabouttheinterioroftheearth.Thethird,ormain.Thethird,ormainwave,istheslowestandhastravelledroundtheearththroughthesurfacerocks.H.H,SWINNERTONTheEarthbeneathUsNewwordsandexpressions生詞和短語(yǔ)earthquaken.地震slumber3v.睡眠ninepinn.九柱戲中的木柱rigidadj.堅(jiān)硬的delicateadj.靈感的seismometern.地震儀penholdern.筆桿legiblyadv.字跡清楚地drumn.鼓狀物wriggle10v.扭動(dòng)bluebottlen.綠頭蒼蠅graphn.圖表graphicadj.圖示的longitudinaladj.縱向的transverseadj.橫向的參考譯文地震就像夜間的小偷，不打招呼就來了。因此，有必要發(fā)明一種儀器，既不打盹兒，也不睡覺。有些裝置非常簡(jiǎn)單。例如，有一種裝置是由一些長(zhǎng)短、粗細(xì)不同的木棒組成，就像九柱戲的木棒一樣堅(jiān)立著，一旦有地震，就會(huì)震動(dòng)豎立在堅(jiān)硬的桌上的木棒。如果地震輕微，只有不穩(wěn)定的木棒倒下；如果地震劇烈，所有的木棒都會(huì)例下。由于地震太弱而未驚醒科學(xué)家時(shí)，木棒倒下的多少和倒下的方向就為科學(xué)家記錄下了地震的強(qiáng)度和地震方向。但是，如果要取得真正重大的進(jìn)展，需要有比這種裝置精細(xì)得多的儀器。理想的目標(biāo)是設(shè)計(jì)出這樣一種儀器：當(dāng)?shù)卣鸢l(fā)生時(shí)，它能用筆在紙上記錄下大地和桌子運(yùn)動(dòng)情況。我寫字時(shí)，筆是移動(dòng)的，紙是靜止的。毫無疑問，經(jīng)過練習(xí)，我最終能夠?qū)W會(huì)筆不動(dòng)而紙動(dòng)來寫字。這聽起來似乎是一種愚蠢的想法，但是早期記錄地震波的儀器（地震儀）正是采用了這中思路。可是，當(dāng)桌子、夾筆裝置、紙都在移動(dòng)時(shí)，怎么能書寫得清楚呢？可以從我們的日常生活觀察中找到這個(gè)問題的答案。一個(gè)站在公共汽車或火車上，當(dāng)車突然開動(dòng)時(shí)，他為什么會(huì)傾倒呢？這是因?yàn)樗哪_動(dòng)了，而他的頭保持著靜止。再做一個(gè)簡(jiǎn)單的實(shí)驗(yàn)可以幫助我們進(jìn)一步理解這個(gè)問題。把一個(gè)生物拴在一根長(zhǎng)繩子的一端，把手高高舉在空中握住繩子，讓重物幾乎接觸地面。然后把手前后左右以及旋轉(zhuǎn)擺動(dòng)，但不要上下擺動(dòng)。結(jié)果會(huì)發(fā)現(xiàn)，重物是動(dòng)了，但動(dòng)得很小，甚至沒動(dòng)。假定把一支筆拴在重物上，筆尖落在地板上的一張紙上，假定地震發(fā)生了，地板、紙、你和你的手都會(huì)動(dòng)，重物和筆卻不動(dòng)。由于紙?jiān)诠P下來回運(yùn)動(dòng)，紙的表面就會(huì)用墨水記錄下地板運(yùn)動(dòng)的情況。根據(jù)這一原理，制造出了最初的地震儀器，但是紙是卷在慢慢放置的圓筒上的。只要一切都是靜止的，筆就會(huì)劃出一條直線；但是，圓筒受到震動(dòng)，筆所畫出的線就會(huì)就會(huì)左右擺動(dòng)。然而，這里所說的儀器記錄下來的只是地震波運(yùn)動(dòng)中的水平部份，地震波的運(yùn)動(dòng)實(shí)際比這要復(fù)雜得多。假如我們真能看到諸如巖石中一個(gè)沙粒子的運(yùn)動(dòng)軌跡，那就像一只嗡嗡叫的綠頭蒼蠅在屋內(nèi)飛行的軌跡，呈現(xiàn)出上上下下、來來回回、左左右右3種性質(zhì)的運(yùn)動(dòng)。已經(jīng)設(shè)計(jì)出了一些儀器，它按照一定的安放方式就可測(cè)繪出這三種運(yùn)動(dòng)的曲線圖。如果把這種儀器安裝在距震源700多英里遠(yuǎn)的地方，曲線記錄就能顯示出前后相同的這3種地震波。首先記錄下的是縱向波的到達(dá)；然后記錄下的是橫向波的到達(dá)，橫向波比縱向波傳播得慢，在縱向波到過幾分鐘后能到達(dá)。這珍兩種波都是穿過地球而來的。正是從這兩種波中的研究中，我們可以了解到地球內(nèi)部的許多情況。第三種波，即主波，是最慢的，是圍繞地球通過表面巖石傳來的。新概念英語(yǔ)正版圖書購(gòu)買點(diǎn)擊收聽單詞發(fā)音

1recording

n.錄音，記錄參考例句：Howlongwilltherecordingofthesongtake?錄下這首歌得花多少時(shí)間？Iwanttoplayyouarecordingoftherehearsal.我想給你放一下彩排的錄像。2vibrations

n.擺動(dòng)(vibration的名詞復(fù)數(shù))；震動(dòng)；感受；（偏離平衡位置的）一次性往復(fù)振動(dòng)參考例句：Wecouldfeelthevibrationsfromthetruckspassingoutside.我們可以感到外面卡車經(jīng)過時(shí)的顫動(dòng)。Iamdrawntothatgirl;Igetgoodvibrationsfromher.我被那女孩吸引住了，她使我產(chǎn)生良好的感覺。來自《簡(jiǎn)明英漢詞典》3slumber

n.睡眠，沉睡狀態(tài)參考例句：Allthepeopleinthehotelswerewrappedindeepslumber.住在各旅館里的人都已進(jìn)入夢(mèng)鄉(xiāng)。Don'twakehimfromhisslumberbecauseheneedstherest.不要把他從睡眠中喚醒，因?yàn)樗枰菹ⅰ?slumbered

微睡，睡眠（slumber的過去式與過去分詞形式）參考例句：Thebabyslumberedinhiscradle.嬰兒安睡在搖籃中。Atthattimemyvirtueslumbered;myevil,keptawakebyambition.就在那時(shí)，我的善的一面睡著了，我的邪惡面因野心勃勃而清醒著。5rigid

adj.嚴(yán)格的，死板的；剛硬的，僵硬的參考例句：Shebecameasrigidasadamant.她變得如頑石般的固執(zhí)。Theexaminationwassorigidthatnearlyallaspirantswereruledout.考試很嚴(yán)，幾乎所有的考生都被淘汰了。6unstable

adj.不穩(wěn)定的，易變的參考例句：Thisbookcaseistoounstabletoholdsomanybooks.這書櫥很不結(jié)實(shí)，裝不了這么多書。Thepatient'sconditionwasunstable.那患者的病情不穩(wěn)定。7slumbering

微睡，睡眠（slumber的現(xiàn)在分詞形式）參考例句：Itwasquiet.Alltheotherinhabitantsoftheslumswereslumbering.貧民窟里的人已經(jīng)睡眠靜了。Thensoftmusicfilledtheairandsoothedtheslumberingheroes.接著，空中響起了柔和的樂聲，撫慰著安睡的英雄。8precisely

adv.恰好，正好，精確地，細(xì)致地參考例句：It'spreciselythatsortofslicksales-talkthatImistrust.我不相信的正是那種油腔滑調(diào)的推銷宣傳。Themanadjustedveryprecisely.那個(gè)人調(diào)得很準(zhǔn)。9standing

n.持續(xù)，地位；adj.永久的，不動(dòng)的，直立的，不流動(dòng)的參考例句：Aftertheearthquakeonlyafewhouseswereleftstanding.地震過后只有幾幢房屋還立著。They'restandingoutagainstanychangeinthelaw.他們堅(jiān)決反對(duì)對(duì)法律做任何修改。10wriggle

v./n.蠕動(dòng)，扭動(dòng)；蜿蜒參考例句：I'vegotanappointmentIcan'twriggleoutof.我有個(gè)推脫不掉的約會(huì)。Childrenwrigglethemselveswhentheyarebored.小孩子感到厭煩時(shí)就會(huì)扭動(dòng)他們的身體。11wriggled

v.扭動(dòng)，蠕動(dòng)，蜿蜒行進(jìn)(wriggle的過去式和過去分詞)；（使身體某一部位）扭動(dòng)；?；蛔?，逃避（應(yīng)做的事等）參考例句：Hewriggleduncomfortablyonthechair.他坐在椅子上不舒服地扭動(dòng)著身體。來自《簡(jiǎn)明英漢詞典》Asnakewriggledacrosstheroad.一條蛇蜿蜒爬過道路。來自《現(xiàn)代漢英綜合大詞典》12apparatus

n.裝置，器械；器具，設(shè)備參考例句：The