萬(wàn)物簡(jiǎn)史:PART II CH 4事物的測(cè)定（25）
來(lái)源：滬江聽(tīng)寫(xiě)酷
2011-09-21 07:00
用來(lái)測(cè)引力常量的設(shè)備很古怪，今天的第二、三段石頭給大家又上了一遍高中物理概念啊，這在當(dāng)時(shí)是卡文迪許要研究的重大課題~~~
?《萬(wàn)物簡(jiǎn)史》推出部落節(jié)目版，戳這里訂閱:http://bulo.hujiang.com/menu/6004/
書(shū)本的朗讀語(yǔ)音很charming的磁性英音~(yú)~~大家可以好好學(xué)著模仿哦~~~??！
因?yàn)樵鵀槊绹?guó)人所寫(xiě),單詞采用美式拼法,不抄全文,然后聽(tīng)寫(xiě)單詞或詞組(用[-No-]表示)以及句子(用[---No---]表示)。請(qǐng)邊聽(tīng)寫(xiě)邊理解文意，根據(jù)上下文注意各句標(biāo)號(hào)，這樣有助于提高正確率。
Hint:
synonymous
Cavendish
When assembled, Michell's [-1-] looked like [-2-] an 18th-century version of a Nautilus weight-training machine. It [-3-] weights, counterweights, pendulums, shafts, and torsion wires. At the heart of the machine were two 350-pound lead balls, which were [-4-] between two smaller spheres. The idea was to measure the gravitational [-5-] of the smaller spheres by the larger ones, which would allow the first measurement of the elusive force known as the gravitational constant, and from which the weight (strictly speaking, the mass) of the Earth could be deduced.
To a physicist, mass and weight are two quite different things. Your mass stays the same wherever you go, but your weight varies depending on how far you are from the center of some other massive object like a planet. Travel to the Moon and you will be much lighter but no less massive. [---6---]
Because gravity holds planets in orbit and makes falling objects land with a bang, we tend to think of it as a powerful force, but it is not really. [---7---] At an elemental level gravity is extraordinarily [-8-] . Each time you pick up a book from a table or a dime from the floor you effortlessly overcome the combined gravitational exertion of an entire planet. [---9---]
?《萬(wàn)物簡(jiǎn)史》推出部落節(jié)目版，戳這里訂閱:http://bulo.hujiang.com/menu/6004/
書(shū)本的朗讀語(yǔ)音很charming的磁性英音~(yú)~~大家可以好好學(xué)著模仿哦~~~??！
因?yàn)樵鵀槊绹?guó)人所寫(xiě),單詞采用美式拼法,不抄全文,然后聽(tīng)寫(xiě)單詞或詞組(用[-No-]表示)以及句子(用[---No---]表示)。請(qǐng)邊聽(tīng)寫(xiě)邊理解文意，根據(jù)上下文注意各句標(biāo)號(hào)，這樣有助于提高正確率。
Hint:
synonymous
Cavendish
When assembled, Michell's [-1-] looked like [-2-] an 18th-century version of a Nautilus weight-training machine. It [-3-] weights, counterweights, pendulums, shafts, and torsion wires. At the heart of the machine were two 350-pound lead balls, which were [-4-] between two smaller spheres. The idea was to measure the gravitational [-5-] of the smaller spheres by the larger ones, which would allow the first measurement of the elusive force known as the gravitational constant, and from which the weight (strictly speaking, the mass) of the Earth could be deduced.
To a physicist, mass and weight are two quite different things. Your mass stays the same wherever you go, but your weight varies depending on how far you are from the center of some other massive object like a planet. Travel to the Moon and you will be much lighter but no less massive. [---6---]
Because gravity holds planets in orbit and makes falling objects land with a bang, we tend to think of it as a powerful force, but it is not really. [---7---] At an elemental level gravity is extraordinarily [-8-] . Each time you pick up a book from a table or a dime from the floor you effortlessly overcome the combined gravitational exertion of an entire planet. [---9---]
apparatus
nothing so much as
incorporated
suspended
deflection
On Earth, for all practical purposes, mass and weight are the same and so the terms can be treated as synonymous, at least outside the classroom.
It is only powerful in a kind of collective sense, when one massive object, like the Sun, holds on to another massive object, like the Earth.
unrobust
What Cavendish was trying to do was measure gravity at this extremely featherweight level.
裝配完畢以后，米歇爾的儀器看上去很像是一臺(tái)18世紀(jì)的鸚鵡螺牌舉重練習(xí)機(jī)。它由重物、砝碼、擺錘、軸和扭轉(zhuǎn)鋼絲組成。儀器的核心是兩個(gè)635千克重的鉛球，懸在兩個(gè)較小球體的兩側(cè)。裝配這臺(tái)設(shè)備的目的是要測(cè)量?jī)蓚€(gè)大球給小球造成的引力偏差。這將使首次測(cè)量一種難以捉摸的力--所謂的引力常數(shù)--成為可能，并由此推測(cè)地球的重量（嚴(yán)格來(lái)說(shuō)是質(zhì)量）。
對(duì)于物理學(xué)家而言，質(zhì)量和重量是兩個(gè)截然不同的概念。無(wú)論在哪兒，物體的質(zhì)量總是不變的，但是物體重量大小的變化取決于其與另一個(gè)如行星那樣的巨大物體的中心距離。在月球上我們會(huì)變得很輕，但是我們的質(zhì)量卻不變。在地球上，為了實(shí)用起見(jiàn)，質(zhì)量和重量數(shù)值上是相等的，因此可以用相近的辦法處理，至少在教室外可以這么做。
引力使行星保持在軌道上，使物體砰然墜落，因此很容易被認(rèn)為是一種強(qiáng)大的力，其實(shí)不然。它只是在整體意義上強(qiáng)大：一個(gè)巨大的物體，比如太陽(yáng)，牽住另一個(gè)巨大的物體，比如地球。在基礎(chǔ)的層面上，引力極小。每次你從桌子上拿起一本書(shū)，或從地板上拾起一枚硬幣，你毫不費(fèi)勁就克服了整個(gè)行星施加的引力?？ㄎ牡显S想要做的，就是在極輕的層面上測(cè)量引力。
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