水太神奇了——世界水資源日！：英語精讀講義

Hey, Vsauce, Michael here and today we are going to talk about water.

嘿，這裡是 Vsauce 的 Michael，今天我們來聊聊水。

Because today is World Water Day, 文化背景

因為今天是世界水資源日，

a day about raising awareness of the fact that even though here on Earth 講解

這個日子旨在讓大家意識到：儘管地球上

there is enough clean safe drinking water for everybody to have enough,

有足夠乾淨、安全的飲用水，足以讓每個人都夠用，

they don't.

卻不是每個人都能取得足夠的水。

In fact, a billion of them don't.

事實上，有十億人無法取得足夠的水。

But it doesn't have to be that way. 文法

但事情不必如此。

Now first,

首先，

I want to cover how water is not just vital and amazing, 文法

我想先談談，水不僅不可或缺、令人驚嘆，

but to this day continues to surprise us. 片語搭配

而且直到今天仍不斷帶給我們驚喜。

For instance,

比方說，

the Mpemba effect. 文化背景

姆潘巴效應。

The effect has been observed many, many, many times, 文法

人們已經無數次觀察到這種效應，

but has never been explained.

卻始終無法解釋它。

In fact, it is so famously anti-common sense,

事實上，它因為如此違反常識而聞名，

whenever people throughout history have observed it,

以至於歷史上每當有人觀察到它時，

they've tended to think that they just did something wrong, 片語搭配

往往都以為只是自己哪裡做錯了，

which is why even though Aristotle himself wrote about it,

所以，儘管亞里斯多德本人就曾寫過這個現象，

it wasn't until the 20th century that it got its name. 文法

它卻直到20世紀才有了自己的名字。

Simply put, 表達脈絡

簡單來說，

the Mpemba effect is the observation that under the right circumstances, 片語搭配

姆潘巴效應是指這樣一種觀察結果：在適當條件下，

a glass of boiling hot water inside a freezer

放在冷凍庫裡的一杯滾燙開水

can turn to ice more quickly than a glass of cold water. 文法

可能比一杯冷水更快結冰。

It doesn't make a lot of sense, 片語搭配

這聽起來不太合理，

but it can happen.

但確實可能發生。

A few possible causes have been thrown out. 片語動詞

人們提出過幾種可能的原因。

For instance,

比方說，

if you heat up or boil water, 片語動詞

如果把水加熱或煮沸，

you remove some of the dissolved gas,

就會去除一部分溶解在水中的氣體，

and having less stuff dissolved in it

而水裡溶解的物質變少，

may be what makes hot water easier to freeze. 文法

也許正是熱水更容易結冰的原因。

It's the opposite of why we throw down salt during wintry weather.

這與我們在寒冷天氣裡往路面灑鹽的原理正好相反。

The salt dissolves into the water,

鹽會溶解在水中，

putting more stuff in it, 文法

讓水裡多出一些物質，

making it more difficult to freeze.

因而更難結冰。

But does that account for the entire effect? 片語動詞

但這能解釋整個效應嗎？

Well,

嗯，

some other possible explanations involve convection currents. 用詞

其他一些可能的解釋涉及對流。

A glass of warm water will contain more cycling convection currents,

一杯溫水中會有更多循環流動的對流，

meaning that the top of that glass of water is warmer.

也就是說，這杯水頂部的溫度會比較高。

And a glass of warm water will tend to freeze from the sides in,

而且，一杯溫水往往會從四周向內結冰，

whereas the glass of cold water 文法

而一杯冷水

will tend to freeze all across the top down.

則往往會從整個頂部往下結冰。

But once that top layer is frozen,

但頂層一旦結冰，

it acts as an insulator. 片語搭配

就會起到隔熱作用。

So all the water below it freezes more slowly.

所以下面的水結冰得更慢。

The point is that 表達脈絡

重點是，

we still do not have a complete explanation of the effect.

我們仍然無法完整解釋這種效應。

Part of the problem is 表達脈絡

問題的一部分在於，

how difficult it is to control every single variable.

要控制每一個變數實在太難了。

Should we be using equal masses of water

我們應該使用質量相同的水，

or equal volumes?

還是體積相同的水？

Should they be in the same freezer

應該把它們放進同一個冷凍庫，

or in separate freezers?

還是分別放進不同的冷凍庫？

And what about evaporation?

那蒸發又該怎麼算？

The warm water will be evaporating faster,

溫水蒸發得更快，

and evaporation into thermosis,

而蒸發是吸熱過程，

it's losing heat more quickly than the cold water.

所以它散失熱量的速度也比冷水快。

It's tough.

這很棘手。

But here's what we do know. 表達脈絡

但有些事我們可以確定。

Earth has a lot of water.

地球上有很多水。

70% of Earth's surface is covered in it.

地球表面的70%都被水覆蓋。

And interestingly enough,

而且很有意思的是，

excluding fat,

如果不計算脂肪，

the human body is about 70% water.

人體約有70%由水構成。

But when you were born,

但你剛出生時，

you were a big old sack of water. 慣用語

簡直就是一大袋水。

That's right.

沒錯。

A new baby is 78% water.

新生兒身體的78%都是水。

Now that number drops to 65%

之後，這個比例會降到65%。

by the time the baby is 1 year old. 文法

寶寶一歲時就會降到這個程度。

And it'll drop even further to about 60% 片語搭配

而且還會進一步降至約60%，

when you're an adult.

等你成為成年

Man,

男性時。

adult women are only about 55% water.

成年女性體內的水分則只占約55%。

This is because women's physiology on average

這是因為，平均而言，女性的身體

contains more fat,

含有更多脂肪，

which doesn't hold as much water

而脂肪不像

as lean tissue.

瘦體組織那樣能留住那麼多水分。

In fact, fat people,

事實上，體脂較高的人，

regardless of gender, 片語搭配

無論性別，

contain less water than thin people.

體內的水分都比瘦的人少。

Earth has a lot of water,

地球上有很多水，

but it's almost all salty.

但幾乎全是鹹水。

96.5% of the water on Earth

地球上96.5%的水

is in the oceans.

都在海洋中。

Another 3.4% of Earth's water

地球上另外3.4%的水

can be found in other large bodies of water 用詞

存在於其他大型水體中，

or frozen inside glaciers or ice caps.

或凍結在冰河或冰帽裡。

But you, me,

但你、我，

all the other animals we see,

以及我們看到的所有其他動物，

other manufactured products,

還有各種人造產品，

they all contain water.

全都含有水。

About .0003%

其中的水量約占0.0003%，

of Earth's total water.

以地球總水量來算。

And all of the storms and clouds and rain and thunderstorms happening

而所有正在發生的風暴、雲、降雨和雷雨

contain only about .0001%

只含有大約0.0001%

of all the water Earth has.

的地球全部水量。

That's a lot of water,

這已經是非常多的水了，

but despite that fact, 表達脈絡

但儘管如此，

almost a billion people on Earth

地球上仍有近十億人

don't have access to potable water. 講解

無法取得可飲用水。

Potable comes from the Latin for to drink,

「potable」一詞源自拉丁文中表示「飲用」的詞，

which means clean,

指的是乾淨、

safe water free from disease and contamination. 片語搭配

安全且不含病原體和污染物的水。

The number of people on Earth

地球上

who do not have sustainable access to potable water

無法持續取得可飲用水的人數，

is equivalent to the number of people 片語搭配

相當於

living inside the United States,

美國的總人口

except multiplied by three.

再乘以三。

And every year,

而且每年，

3 and 1/2 million people die

有350萬人死亡，

because of non-potable water-related diseases. 用詞

原因是與不可飲用水有關的疾病。

That's equivalent to the entire population of Los Angeles.

這相當於洛杉磯的全部人口。

So every year,

所以每年，

Earth,

地球——

our planet,

我們的星球——

loses an entire city of Los Angeles 慣用語

都會失去相當於整個洛杉磯市的人口，

because people don't have access to clean water.

只因為人們無法取得乾淨的水。

So today on World Water Day,

因此，在今天這個世界水資源日，

it's worth talking about organizations

值得談談那些

that are making a difference 慣用語

正在帶來改變的組織，

because things don't have to be the way that they are. 表達脈絡

因為現況並非無法改變。

Organizations like water.org

像 water.org 這樣的組織

help local communities build sustainable clean water solutions

會協助當地社區建立永續的乾淨用水方案，

that the community itself will own. 文法

而這些方案將歸社區自己所有。

Now,

那麼，

they gave me a chance to go out to India 片語搭配

他們給了我一個前往印度的機會，

to see this in action, 片語搭配

讓我親眼看看這項工作如何進行，

along with WheezyWaiter

同行的還有 WheezyWaiter

and Strawberry17.

和 Strawberry17。

Unfortunately,

可惜的是，

I wasn't able to go, 文法

我沒能成行，

but those other two people were,

但另外兩位去了，

and they've got videos over on their channels

而且他們已在各自的頻道上傳影片，

about their experiences.

分享自己的親身經歷。

So go check those out.

所以快去看看吧。

And if you want to learn more,

如果你想了解更多，

go to water.org/vsauce

請前往 water.org/vsauce，

to see how you can help.

看看自己能如何提供協助。

And as always,

一如往常，

thanks for watching.

謝謝收看。