## 字幕列表 影片播放

• An apple weighs about 1 newton, the world record for jet engine thrust is 570,000 newtons.

一顆蘋果的重量大約是1牛頓 (譯注: 1牛頓約等於102公克重)

• And the Saturn V rocket that launched people to the moon had a thrust of 33,360,000 newtons

噴射引擎推力的世界紀錄則是57萬牛頓

• But how can we measure forces this big accurately?

載人登月計畫使用的土星五號火箭推力高達3千3百萬牛頓

• Well, we need to ask this guy.

話說回來，這麼大的力量我們是如何精確測量出來的呢？

• Hi my name is Rick Seifarth I'm a physical scientist in the Mass and Force Group.

這個問題讓我們找個專家來回答

• Am I supposed to look at the camera?

大家好，我叫Rick Seifarth，我是國家標準技術研究所(NIST)的物理學家

• Sure.

我應該要看著鏡頭講話吧？

• Okay.

不然呢？

• You can look at anything you like.

好吧！

• Rick manages a dead weight machine that can apply 4,448,222 newtons.

隨便你想看哪裡啦！(哈哈)

• Why such a strange number? Because that's exactly equal to 1,000,000 pounds of force.

Rick負責管理一台靜荷重設備，可提供高達4,448,222牛頓的力

• There are twenty fifty thousand pound increments in this machine

為什麼會是這個怪怪的數字？因為它剛好等於1百萬磅的力

• 20 times 50 equals 1,000,000 pounds.

這台機器裡面有20個50,000磅重的砝碼

• Cumulatively that's 4.45 mega newton.

20 x 5,0000磅 = 1,000,000磅

• Elsewhere in the world, are there larger masses that people have calibrated?

累計起來就是約445萬牛頓

• I ask that question to every visitor we get and I've not gotten..

這世界上有沒有其他人曾校準過比你們這裡更大重量的砝碼？

• one response that says: yeah I know where bigger stuff is calibrated.

這個問題我問過每一位參觀來賓，目前還沒有得到一個回答是：

• So if I really want to go out on a limb and brag I'll say

"有啊！真的有人校準過更大的東西！"

• these are the largest mass objects ever calibrated.

所以如果我真的想要出去大肆吹噓的話

• Anywhere

我敢說這些絕對是迄今被校準過的最大砝碼

• The machine works like this, below ground are the 20 carefully calibrated masses.

全世界最大的

• Their weight is used to calibrate force sensors also called

這機器的工作原理如下：在地面以下有20個經校準的砝碼

• Force Transducers, in the lab upstairs.

它們的重量被用來校準位於實驗室樓上的"力傳感器" (Force Transducer)

• This is a one million pound capacity 4.45 mega newton,

這個"力傳感器"可測到1百萬磅，相當於445萬牛頓

• and this is 13.3 mega newtons, three million pounds force.

這個則可以測到3百萬磅，相當於1,335萬牛頓的力

• This is the biggest machine of it's type in the world, and obviously one of a kind.

這台機器是這世界上同類型中最大的一台 ，所以顯然是獨一無二的

• One of these,

其中之一，

• will be placed on the compression head right here.

將被放置在這裡的重壓台上

• Then, a hydraulic ram in the attic starts to raise the green lifting frame

然後，在閣樓上的液壓油缸開始拉起 綠色升降架

當"力傳感器"接觸到紅色負載架時

• well then it starts lifting the weights downstairs.

它就開始拉動樓下的砝碼

• And as the lifting frame continues to rise, more and more of the

隨著升降架繼續上升，越來越多的

• 50,000 pound weights become suspended by the force sensor.

50000磅砝碼被"力傳感器"懸吊起來

• And since the weights create an accurately-known force,

由於這些砝碼提供了精確的已知力

• the readouts from the force transducer can be precisely calibrated.

就可以用來精密地校準當下"力傳感器"的讀數

• These devices are then sent out into the field.

然後，這些已校準的"力傳感器"就可以送到現場使用。

• Well literally, there's a test stand that's set up with one of these gizmos-

舉例來說，有一種試驗台就有使用"力傳感器"這個元件

• a force transducers - embedded in the test stand somewhere.

它被嵌入在試驗台的某處

• And so the rocket is fired up, perhaps ramped up, ramped down and those forces are monitored.

當火箭被發動時，不論是逐步加速或減速，過程中的推力值都可以被監控

• You know, in the old movies you'd hear: "go to 104% of power." Well, how do they know it's 104% of power?

你在電影某幕中可能會聽到指令：“推力設定104％”，那麼他們是如何確定它真是104％？

• Because somebody's measured it somewhere.

那是因為某處有人正在測量它

• When it comes to minimizing uncertainty, these guys aren't messing around.

當談到盡量降低不確定性，這些傢伙可沒有掉以輕心

• This piece right here is approximately 50,036.27 pounds of mass.

這裡的一塊砝碼重量約為50,036.27磅

• Approximately.

只是大約？

• Approximately, yes! [laughter]

就是大約！ [笑聲]

• Think about that for a moment.

讓我們停下來思考一下

• Each of these pieces has a mass equivalent to ten minivans,

這些砝碼中旳每一個重量都相當於10台休旅車

• and their exact value is known to within several American nickels.

而它們的重量誤差值卻只相當於幾枚五分錢硬幣

• Just a few American nickels worth of difference?

只有幾枚五分錢硬幣的差異？？

• Yeah.

沒錯！

• That tiny uncertainty is measured with respect to the very definition of the kilogram

對於這樣微小不確定性的測定是基於千克的定義："K20"原型

• using K20 - that's the United States fundamental mass standard.

這是美國的基本質量1千克標準品

• This is done by comparing combinations of known weights, starting with K20, with larger unknown weights,

這是通過從1千克(K20)開始的已知砝碼組合，和其他較大未知砝碼相比較來完成

• gradually working up to larger and larger masses.

逐步往上到越來越大重量的砝碼

• For example, here a single 5-kilogram mass is compared to two 2s and a 1.

例如，這裡有一個5千克的砝碼正在與一組由兩個2千克和一個1千克砝碼的組合來相比較

• At some point in this process, they convert and start working in pounds, going from 50-pound masses to 500 pounds,

在這過程中的某些階段，它們的單位將開始由千克轉換為磅，然後從50磅重的砝碼進行到500磅

• and then 2500 pounds. And then, using a scale in the floor, to reach 10,000 pounds and then 20,000,

再來到2,500磅。然後轉到落地型的大型磅秤，以達到10,000磅、20,000磅、

• and finally 30,000 pounds.

最終達到30,000磅

• Combinations of these huge weights are then used to calibrate the 50,000-pound masses which form the weight stack.

然後再用這些巨大的砝碼的組合來校準這些將用作於配重片的50,000磅砝碼

• And we have to have that, because what we sell is the vertical force vector that's generated by these weights

我們必須不厭其煩，因為這就是我們提供的服務：由這些配重片懸在重力場中所產生的精準垂直力矢量

• hanging in a gravitational field. We sell that with an uncertainty attached to it of 0.0005%,

我們服務的價值在於誤差只有0.0005％的精確度

• five parts per million, so that means at full one million pounds of applied force, we guarantee that to be accurate - if you will -

百萬分之五的誤差，意謂著在100萬磅的推力量測裡，如果你能接受5磅以內的不確定性，

• within five pounds.

我們可以保證數值的準確性

• Not only does that mean the masses have to be accurately calibrated,

然而，這不僅僅代表著這些配重片必需被精密地校準

• it also means the gravitational acceleration at this location has to be taken into account.

同時這也代表必須考慮到所在位置的重力加速度

• It's actually slightly less than Earth's standard gravity, so an additional 600 pounds are required.

因為所在地的地心引力實際上略小於地球的標準引力，因此需要補足額外的600磅重

• Plus, the buoyant force must be counteracted,

除此之外，還有空氣浮力必須被抵消

• since these masses displace 125 pounds of air,

因為這些配重片的體積所排除的空氣量為125磅 (產生125磅的浮力)

• a further 125 pounds must be added to reach a million pounds of force.

因此必須再加上125磅才能真正補足100萬磅的力

• What strikes me as kind of amazing is that, like, this machine needs to exist, in a way.

想到這台機器在某些方面上存在的必要性，讓我感到驚奇不已

• When I would have thought about it, like how would Boeing measure its forces, I would have thought

我曾好奇波音公司如何測量它的引擎推力量，我真有想過這事

• OK, they just, you know, calibrate a device that works up to X but then they can, you know,

他們也就只是依樣校準到若干個配重片

• generalize. Well, generalize - you know what I mean, like - Yes!

概括化。那麼，概括化 - 你知道我的意思，就像 - 是的！

• There's an axiom that says "one physical test is worth a thousand expert opinions."

有句至理名言：“一個物理測試抵得上一千名專家的意見”

• And that has proven itself time and again, particularly in the world of physical testing.

這句話經得起千錘百煉，尤其是在物理測試的領域

• If you're getting on an airplane that somebody has built, are you willing to accept a 10% uncertainty on these numbers

如果某人建造了一架飛機，它建造過程中的量測不確定性達到10%，你會敢坐嗎？

• or do you want it to be - the uncertainty on these measurements to be down in the mud?

或者你希望這些測量的不確定性能夠低到仆街？

An apple weighs about 1 newton, the world record for jet engine thrust is 570,000 newtons.

B2 中高級 中文 牛頓 傳感器 重量 推力 不確定性 機器

# 世界上最重的重量 (World's Heaviest Weight)

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林宜悉 發佈於 2021 年 01 月 14 日