水太神奇了——世界水日！：英语精读讲义

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

嘿，这里是 Vsauce 的 Michael，今天我们来聊聊水。

Because today is World Water Day, 文化背景

因为今天是世界水日，

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

这个日子旨在让人们意识到：尽管在地球上

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

有足够的清洁、安全的饮用水，足以让每个人都够用，

they don't.

但并非人人都能获得足够的水。

In fact, a billion of them don't.

事实上，有十亿人无法获得足够的水。

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

但事情不必如此。

Now first,

首先，

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

我想先说说，水不仅至关重要、令人惊叹，

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

而且直到今天仍不断带给我们惊喜。

For instance,

比如，

the Mpemba effect. 文化背景

姆潘巴效应。

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

人们已经无数次观察到这种效应，

but has never been explained.

却始终无法解释它。

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

事实上，它因如此违背常识而闻名，

whenever people throughout history have observed it,

以至于历史上每当有人观察到它时，

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

往往都以为只是自己哪里做错了，

which is why even though Aristotle himself wrote about it,

所以，尽管亚里士多德本人就曾写过这个现象，

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

它却直到20世纪才有了自己的名字。

Simply put, 表達脈絡

简单来说，

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

姆潘巴效应是指这样一种观察结果：在适当条件下，

a glass of boiling hot water inside a freezer

放在冰柜里的一杯滚烫的开水

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

可能比一杯冷水更快结冰。

It doesn't make a lot of sense, 短語搭配

这听起来不太合理，

but it can happen.

但确实可能发生。

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

人们提出过几种可能的原因。

For instance,

比如，

if you heat up or boil water, 短語動詞

如果把水加热或煮沸，

you remove some of the dissolved gas,

就会去除一部分溶解在水中的气体，

and having less stuff dissolved in it

而水里溶解的物质变少，

may be what makes hot water easier to freeze. 語法

也许正是热水更容易结冰的原因。

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

这与我们在寒冷天气里往路面撒盐的原理正好相反。

The salt dissolves into the water,

盐会溶解在水中，

putting more stuff in it, 語法

让水里多出一些物质，

making it more difficult to freeze.

从而更难结冰。

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

但这能解释整个效应吗？

Well,

这个嘛，

some other possible explanations involve convection currents. 用詞

其他一些可能的解释涉及对流。

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

一杯温水中会有更多循环流动的对流，

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

也就是说，这杯水顶部的温度会更高。

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

而且，一杯温水往往会从四周向内结冰，

whereas the glass of cold water 語法

而一杯冷水

will tend to freeze all across the top down.

则往往会从整个顶部向下结冰。

But once that top layer is frozen,

但顶层一旦结冰，

it acts as an insulator. 短語搭配

就会起到隔热作用。

So all the water below it freezes more slowly.

所以下面的水结冰得更慢。

The point is that 表達脈絡

关键在于，

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

我们仍然无法完整解释这种效应。

Part of the problem is 表達脈絡

问题的一部分在于，

how difficult it is to control every single variable.

要控制每一个变量实在太难了。

Should we be using equal masses of water

我们应该使用质量相同的水，

or equal volumes?

还是体积相同的水？

Should they be in the same freezer

应该把它们放进同一个冰柜，

or in separate freezers?

还是分别放进不同的冰柜？

And what about evaporation?

那蒸发又该怎么算？

The warm water will be evaporating faster,

温水蒸发得更快，

and evaporation into thermosis,

而蒸发是吸热过程，

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

所以它散失热量的速度也比冷水快。

It's tough.

这很棘手。

But here's what we do know. 表達脈絡

但有些事我们可以确定。

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%都被水覆盖。

And interestingly enough,

而且很有意思的是，

excluding fat,

如果不计算脂肪，

the human body is about 70% water.

人体约有70%由水构成。

But when you were born,

但你刚出生时，

you were a big old sack of water. 習語

简直就是一个大水袋。

That's right.

没错。

A new baby is 78% water.

新生儿身体的78%都是水。

Now that number drops to 65%

之后，这个比例会降到65%。

by the time the baby is 1 year old. 語法

宝宝一岁时就会降到这个水平。

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

而且还会进一步降至约60%，

when you're an adult.

等你成为成年

Man,

男性时。

adult women are only about 55% water.

成年女性体内的水分则只占约55%。

This is because women's physiology on average

这是因为，平均而言，女性的身体

contains more fat,

含有更多脂肪，

which doesn't hold as much water

而脂肪不像

as lean tissue.

瘦体组织那样能储存那么多水分。

In fact, fat people,

事实上，体脂较高的人，

regardless of gender, 短語搭配

无论性别，

contain less water than thin people.

体内的水分都比瘦人少。

Earth has a lot of water,

地球上有很多水，

but it's almost all salty.

但几乎全是咸水。

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

存在于其他大型水体中，

or frozen inside glaciers or ice caps.

或冻结在冰川或冰盖里。

But you, me,

但你、我，

all the other animals we see,

以及我们看到的所有其他动物，

other manufactured products,

还有各种人造产品，

they all contain water.

全都含有水。

About .0003%

其中的水量约占0.0003%，

of Earth's total water.

以地球总水量计。

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

而所有正在发生的风暴、云、降雨和雷暴

contain only about .0001%

只含有大约0.0001%

of all the water Earth has.

的地球全部水量。

That's a lot of water,

这已经是非常多的水了，

but despite that fact, 表達脈絡

但尽管如此，

almost a billion people on Earth

地球上仍有近十亿人

don't have access to potable water. 講解

无法获得可饮用水。

Potable comes from the Latin for to drink,

“potable”一词源自拉丁语中表示“饮用”的词，

which means clean,

指的是洁净、

safe water free from disease and contamination. 短語搭配

安全且不含病原体和污染物的水。

The number of people on Earth

地球上

who do not have sustainable access to potable water

无法持续获得可饮用水的人数，

is equivalent to the number of people 短語搭配

相当于

living inside the United States,

美国的总人口

except multiplied by three.

再乘以三。

And every year,

而且每年，

3 and 1/2 million people die

有350万人死亡，

because of non-potable water-related diseases. 用詞

原因是与不可饮用水有关的疾病。

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

这相当于洛杉矶的全部人口。

So every year,

所以每年，

Earth,

地球——

our planet,

我们的星球——

loses an entire city of Los Angeles 習語

都会失去相当于整个洛杉矶市的人口，

because people don't have access to clean water.

只因为人们无法获得清洁用水。

So today on World Water Day,

因此，在今天这个世界水日，

it's worth talking about organizations

值得谈谈那些

that are making a difference 習語

正在带来改变的组织，

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

因为现状并非无法改变。

Organizations like water.org

像 water.org 这样的组织

help local communities build sustainable clean water solutions

会帮助当地社区建立可持续的清洁用水方案，

that the community itself will own. 語法

而这些方案将归社区自己所有。

Now,

那么，

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

他们给了我一个前往印度的机会，

to see this in action, 短語搭配

让我亲眼看看这项工作如何开展，

along with WheezyWaiter

同行的还有 WheezyWaiter

and Strawberry17.

和 Strawberry17。

Unfortunately,

遗憾的是，

I wasn't able to go, 語法

我没能成行，

but those other two people were,

但另外两位去了，

and they've got videos over on their channels

而且他们已在各自的频道上传了视频，

about their experiences.

分享自己的亲身经历。

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

请访问 water.org/vsauce，

to see how you can help.

看看自己能如何提供帮助。

And as always,

一如既往，

thanks for watching.

感谢观看。