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为什么“千克”的质量变了? – 译学馆
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为什么“千克”的质量变了?

The kilogram has changed forever. Here’s why.

I grew up in the United States,
我在美国长大
which means I used pounds and ounces
这意味着我用磅和盎司
to measure everything that I used growing up
来衡量我遇到的一切
except maybe soda bottles.
除了汽水瓶
Right, and I grew up in the U.K.
是的 我在英国长大
where I use the metric system for pretty much everything
我几乎什么都用公制单位
and pounds are what I pay for things in the store with.
我在商店里用英镑买东西
So while we don’t really
虽然我们
agree on a unit of measurement yet, there is one thing
还没有统一单位 但有个东西
that everyone should be familiar with,
每个人都应该很熟悉
and that’s the kilogram.
那就是公斤
Right, and not just because
是的 不仅仅是因为
it’s a superior unit of measurement
它是一个高级的单位
or because it’s used pretty much everywhere in the world,
或者因为它在全球使用非常广泛
but because it recently changed.
更因为它最近有了变化
[rhythmic drumming]
[有节奏的鼓声]
How much does a kilogram weigh?
一公斤重多少?
This is not a trick question.
这不是脑筋急转弯
When the kilogram was first introduced
当公斤第一次被
as a unit of mass in the 18th century,
作为18世纪的重量单位时
it was decreed to be the absolute weight
它被规定为
of a volume of pure water equal to the cubeof the 100th part of the meter. (Correction: the 10th part)
一立方分米纯净水的重量
Basically, one cubic decimeter, or one liter.
一立方分米也就是一升
About this much.
大概这么多
Anyway, the French scientist who came up
不过 下定义的法国科学家
with this definition soon discovered it was a little sloppy.
很快发现这样有点草率
The weight of the water changes depending on things like purity and atmospheric pressure.
水的重量因纯度和大气压等因素而变化
So they’ve replaced that definition with something like this.
所以他们用这个东西代替了这个定义
For more than a hundred years,
一百多年来
a metal artifact similar to this has been the definition
类似的金属制品被作为了
of the kilogram.
公斤的定义
The real one is made of platinum iridium
最初的那块是由铂铱制成的
and it’s called the International Prototype Kilogram.
它被称为国际原型公斤
Since 1889, it’s been kept under lock and key
自1889年以来 它一直被锁在
in a vault on the outskirts of Paris.
巴黎郊区的一个保险库中
The Prototype Kilogram has been a big deal.
千克的原型非常重要
Think about it.
想想看
If we didn’t have reliable units of weight,
如果我们没有可靠的重量单位
how would countries trade?
各国如何进行贸易?
How would scientists repeat experiments and share their results?
科学家如何重复实验并分享他们的发现?
How could you trust a recipe or even your bathroom scales?
你怎么相信食谱 甚至你的浴室秤?
That little chunk of metal is the foundation of the modern world.
那一小块金属是现代世界的基础
But recently, scientists voted to get rid of it
但是最近 科学家投票决定要摆脱它
and they replaced it with something far, far stranger.
他们把它换成了一个非常非常奇怪的东西
[rhythmic drumming]
[有节奏的鼓声]
Last month, I visited the headquarters of
上个月 我参观了
the International Bureau of Weights and Measures in France,
国际度量衡局在法国的总部
the body that acts as the guardian of the metric system
该机构是公制的守护者
and I watched as delegates from 60 countries voted
我看到来自60个国家的代表投票
to retire the Prototype Kilogram.
决定淘汰千克的原型
It was amazing to see.
真是太神奇了
Each country standing up to vote one by one
各代表一个接一个地站起来投票
and then the whole hall erupts into applause and congratulations.
然后整个大厅爆发出掌声和祝贺
[applause]
[掌声]
For some of the scientists there,
对于那的一些科学家
it was the culmination of a lifetime of work,
这是他们毕生努力的结晶
slimming down the world’s system of measurement
精简了世界的测量系统
so that all the definitions now fit onto a single card.
使所有定义现在都可以放入一张卡中
[contemplative music]
[冥想音乐]
But before we get into that,
但在我们开始之前
let’s think about how weights work in general.
我们先想想重量的工作原理
We know that the Prototype Kilogram
我们知道原型公斤
and its successor define standards of weights around the world,
及其后继者定义了全球重量标准
but if you grab some scales
但是如果你拿一些秤
and weigh out a kilogram of flour,
称出一公斤面粉
how do those scales know how much a kilogram weighs?
那些秤怎么知道一公斤重多少?
Well, we called some scale companies to find out.
好 我们打电话给称重公司调查
– [Phone Voice] Hello, how may I help you?
-[电话语音]您好 请问您需要什么?
– Can you tell me how you go
您能告诉我如何
about calibrating your scales,
校准你们的秤
how do you make sure that they’re accurate?
如何确保秤的准确性?
– [Cory] Here’s what we learned.
-[科里]我们了解到
Basically, a scales company
基本上 一个称重公司
like Escali buys calibration weights to place on their scales
像Escali 购买校准砝码放在秤上
and dial them in.
然后拨入
A weight like this one was measured against an even more
像这样的重量是用更精确的千克
accurate kilogram, which itself might be measured against an even
来测量的 而该千克本身可能是用
more accurate kilogram,
更精确的千克来测量的
all the way up the ladder of accuracy,
不断精进准确性
until, in the U.S. anyways, it reaches
直到在美国 不管怎样 它精确到了
the National Institute of Standards and Technology.
国家标准和技术研究所中的千克
They have a couple of very special artifacts:
它们有两件非常特别的文物:
two of the 40 original weights that were measured directly
1889年直接根据国际原型公斤测量的
against the International Prototype Kilogram in 1889.
40个原始砝码中的两个
And they numbered them from one to 40
他们从1到40给砝码编号
and they screwed one number up and they
他们弄乱了一个数
left out eight and numbered it 41 by mistake.
不小心漏了8 并标到了41
[laughs]
[笑声]
Small little detail.
小细节
[Cory] That’s Stefan Schlamminger, a physicist at NST.
[科里]Stefan Schlamminger NST的物理学家
He says there was a global raffle
他说 全球范围内有抽奖活动
for countries to get the 40 original weights.
让各国获得40个重量原型
And the United States got two: number four and number 20.
美国有两个:第四号和第二十号
[Cory] Today there are more than just 40.
[科里]现在不止40个了
New ones are measured against a final,
新的砝码是根据一个最终的
ultra-accurate stand-in for the IPK,
超精确的原型替代标准来测量的
called the Working Standard.
称为“工作标准”
The Working Standard is basically used to
现在工作标准基本上是用来
calibrate now all masses from all nations.
校准所有国家的重量
That’s how things used to work,
这就是过去的工作方式
but with the redefinition last month,
但随着上个月的重新定义
instead of tracing weights back to the Prototype Kilogram,
不再把重量追溯到原型公斤
there’s a new top boss.
而是有了一个新的最高标准
The kilogram is no longer a lump of metal,
千克不再是一块金属
it’s a constant of nature.
而是一个自然常数
[godly chorus sings]
[神圣的合唱]
The kilogram isn’t the first unit to go through this change.
千克不是第一个经历这种变化的单位
In fact, it’s the last.
事实上 它是最后一个
The meter, for example, was once defined as one
例如 米曾经被定义为
ten-millionth of the distance from the North Pole to the Equator,
从北极到赤道的距离的1千万分之一
a length that was enshrined in a physical artifact.
这一长度被刻在一件实物上
Now, it’s defined as the distance that light travels
现在 它被定义为光在
in a tiny fraction of a second, about a 300 millionth.
短短的一秒钟内传播的距离的约三百万分之一
The kilogram, on the other hand, is now tied
而公斤 现在和
to the smallest action that can be made by a photon,
光子所能进行的最小动作有关
which is essentially the smallest possible physical action there is.
这实际上是光子可能发生的最小动作
It’s called Planck’s Constant
它被称为普朗克常数
and in order to tie mass to it,
为了将质量与之联系在一起
scientists had to create one of these,
科学家们不得不创造了这个
a Kibble Balance.
即“粗磨平衡”
It works like an old-fashioned balance beam,
它的工作方式类似于老式的平衡木
but instead of weighing one mass against another,
但它不是将两个质量相称
it weighs one mass against an electromagnetic force.
而是将其与电磁力相称
This force can be measured with extreme precision using Planck’s Constant
该力可以用普朗克常数以极高精度测量
and this will be the new definition of the kilogram.
这将是千克的新定义
But look, there’s one question we’ve not talked about so far.
但是 我们还没有讨论一个问题
Why?
为什么?
Why are we going to all this trouble?
我们为什么要这么麻烦?
Well, when I spoke to the scientists at the big vote last month,
好吧 我上个月在大票上与科学家们交谈时
they gave me two reasons.
他们给了我两个理由
First, accuracy.
第一 准确性
The problem with using a physical standard to
使用物理标准来定义千克
define the kilogram is that physical objects change.
问题在于物质会变化
None of them last forever.
没有物质是永恒的
And over the past few decades, the Prototype Kilogram itself has lost mass.
在过去的几十年中 原型公斤本身已经减轻了
Not much, about 50 micrograms,
不多 大约50微克
or the weight of a human eyelash, but still,
即人类睫毛的重量 但仍然
thanks to that huge chain
根据我们追踪的
of calibrations we traced,
巨大校准链
technically every kilogram in the world ends up shifting
从技术上讲 世界上每公斤的重量最终
by one eyelash weight.
都会少一个睫毛的重量
Not ideal.
不太理想
But more importantly, they said it was about ideology.
但更重要的是 他们说这与意识形态有关
The Prototype Kilogram is based in France
原型公斤是法国制造的
because it was created during the French Revolution.
因为它是在法国大革命期间创建的
This was a time when revolutionaries were tearing down
那时革命者正在废除
and reconstructing so many of society’s norms.
并重建许多社会规范
And that included weights and measurements.
包括重量和尺寸
They wanted to make units that were consistent,
他们想建立一个统一的单位
that were fair to the working man and woman.
这对劳动的男女平等
And that was shared between countries.
这是各国之间的共识
They wanted to unite the world.
他们想团结世界
Their motto was”Pour tous les temps,
他们的座右铭是“为了永恒
“pour tous les peuples, for all time, for all people.”
为了人民“
But if we define mass using
但是 如果我们使用
a single Prototype Kilogram locked away
锁在法国地下室中的单个原型公斤
in a basement in France,
来定义质量
then it can’t be for all men and for all women.
那么它不可能适用于所有男性和女性
And if it changes when we measure it,
而且 如果我们测量时它变化了
it can’t be for all time.
它就不符合”永恒“
So the scientists say by tying the kilogram
因此 科学家说 通过将公斤
to a constant of nature, we are,
与自然界联系在一起 我们可以
in a way, freeing it from its physical constraints.
从某种程度上摆脱其物理约束
We’re achieving the dream of the creators of the metric system,
我们正在实现度量系统创建者的梦想
a journey that’s been centuries in the making.
这是一个历经数百年的旅程
Planck’s Constant is something,
普朗克常数
it’s woven into the fabric of the universe,
植根于宇宙的结构中
so everybody can access it.
所以每个人都能接触到它
And I think that opens a whole world.
我认为这会打开整个世界
[claps]
[鼓掌]
[Man Offscreen] Um.
[屏外声]嗯
Ah.

[claps]
[鼓掌]
[laughs]
[笑声]
[claps and laughs]
[鼓掌和笑声]
Sorry I’ll stop laughing when I do that eventually.
对不起 我真正开始时不会笑的

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视频概述

从浴室的秤到医学实验室天平,其背后的质量标准现在已经转变为一个基于“植根于宇宙结构中”的值。

听录译者

收集自网络

翻译译者

YvonneYY

审核员

审核员DY

视频来源

https://www.youtube.com/watch?v=m-fFRLWBzm8

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