屁的科學：英語精讀講義

Hey, Vsauce. Michael here.

嘿，這裡是 Vsauce，我是 Michael。

And today we are going to talk about farts.

今天我們要來聊聊屁。

What are they?

屁到底是什麼？

How do they define us?

它們如何定義我們？

And how much weight do we lose every time we fart?

每放一次屁，我們會減輕多少體重？

Now, it's easy to think that talking about farts is immature, 文法

一提到聊屁，很容易讓人覺得這很幼稚，

but they are incredibly complicated.

但屁其實複雜得難以置信。

And by analyzing them because they're funny, 文法

當你因為覺得好笑而分析屁時，

you can accidentally learn a lot of science.

可能會意外學到許多科學知識。

Plus, we are in great company. 慣用語

而且，跟我們同道的可都是大人物。

Mozart wrote songs and poems about flatulence,

莫札特曾寫過關於脹氣的歌曲和詩，

and even Benjamin Franklin once wrote an essay titled Fart Proudly.

就連班傑明・富蘭克林也寫過一篇題為〈自豪地放屁〉的文章。

So, first things first, 片語搭配

那麼，先從最基本的問題說起：

where do farts come from?

屁是從哪裡來的？

A lot of the gas that makes up a fart comes from the outside 片語動詞

組成屁的氣體有很大一部分來自外界，

because you swallowed it.

因為是你把它吞進去的。

That's right.

沒錯。

You swallow a lot of air when swallowing spit or food or beverage.

吞口水、食物或飲料時，你會吞下大量空氣。

Now, some of this will come back up as a burp.

其中一部分會化成嗝，從上面跑回來。

But if it doesn't soon enough, 片語搭配

但如果它沒有及時出來，

it will go deeper into your digestive system.

就會進入消化系統更深處。

But it's where the other portion of the gas

但組成屁的另一部分氣體

that makes up a fart comes from that makes farts so unique.

來自哪裡，才是屁如此獨特的關鍵。

No two people's farts smell alike. 文法

沒有兩個人的屁聞起來一模一樣。

The pungent part of a fart is unique to you,

屁裡那股刺鼻的氣味是你獨有的，

and it comes from things that are inside you and are not you.

它來自你體內那些並不屬於「你」的東西。

Inside your intestines are completely separate organisms, 文法

你的腸道裡住著一些完全獨立的生物，

bacteria and microbes that digest food you haven't or can't.

也就是細菌和微生物，它們會消化你尚未或無法消化的食物。

Now, these little guys have a great collective name,

這些小傢伙有個很棒的統稱：

gut flora. 用詞

腸道菌叢。

And because they are so much smaller than the average human cell, 文法

因為它們比一般人體細胞小得多，

their numbers are staggering. 用詞

所以數量多得驚人。

Believe it or not, your body contains about 10 trillion cells. 語氣意圖

信不信由你，人體大約有10兆個細胞。

But the number of bacteria and microorganisms inside your intestines

但你腸道內的細菌和微生物數量

is nearly 100 trillion.

卻接近100兆。

As these microorganisms digest food that you haven't or can't,

當這些微生物消化你尚未或無法消化的食物時，

they produce helpful things like vitamin K.

會產生維生素K等有益物質。

But they also produce chemicals

但它們也會產生一些化學物質，

that lead to the reason that farts smell. 片語搭配

而這正是屁會臭的原因。

And we all fart every day,

而且我們每個人每天都會放屁，

about a pint of fart every day.

每天放出的屁大約有一品脫。

And if you say that you don't fart,

如果你說自己從不放屁，

you probably release that gas when you're in the bathroom

那你很可能是在上廁所時排出那些氣體，

or at night when you're asleep and your muscles are more relaxed.

或是在晚上睡著、肌肉比較放鬆時排出去。

But if this amount of gas used to be inside you, 文法

可是，如果這麼多氣體原本在你體內，

and now it's not,

現在卻不在了，

that must mean that every time you fart you lose mass,

那就表示每次放屁，你都會失去一些質量，

you lose weight.

也就是減輕一些體重。

But how much weight?

但到底會輕多少？

Well, luckily, some researchers have already figured this out. 片語動詞

幸好，已經有研究人員算出答案了。

Assuming this average chemical makeup of a fart, 文法

假設屁的平均化學組成是這樣，

and what studies have shown is the typical volume of a fart,

再加上研究顯示的典型單次屁量，

it can be calculated 文法

就可以算出，

that the average fart weighs about 3/100 of a gram.

一個屁平均重約3/100公克。

And the part of it that actually stinks only weighs 0.0008 grams.

其中真正發臭的部分只有0.0008公克。

Okay, so a fart weighs 3/100 of a gram.

好吧，也就是說，一個屁重3/100公克。

I mean, what does that really mean? 表達脈絡

可這到底代表什麼？

Well, here's a fun way to think about it. 表達脈絡

可以用一種有趣的方式來想。

As you move further away from the center of the Earth, 文法

當你離地心愈來愈遠時，

the gravitational attraction between the two of you decreases and your weight decreases.

你和地球之間的引力會減弱，體重也會下降。

In fact, according to this fantastic book about the scale of things, 片語搭配

事實上，根據這本探討萬物尺度的精彩著作，

your weight decreases by about 0.5% for every 6 mi you are above Earth.

你每升到離地球表面6英里的高度，體重就會減少約0.5%。

In fact,

其實，

the average fart causes you to lose an amount of weight

一般人放一次屁所減輕的體重，

equivalent to being about a third of an inch further from Earth. 片語搭配

相當於讓你離地球遠了大約1/3英吋。

The way your gut flora process the food that you eat and influence how your farts smell

腸道菌叢處理你吃下的食物並影響屁味的方式，

was established within the first 2 to 3 months of your life.

在你出生後的頭兩三個月內就已經確立。

When you're first born,

你剛出生時，

your gastrointestinal tract is completely sterile. 用詞

胃腸道是完全無菌的。

There are no microorganisms living in it.

裡面沒有任何微生物。

In fact, unlike the rest of your life,

事實上，這和你往後的人生不同，

the very first poop that you take is almost completely sterile.

你這輩子第一次排出的便便幾乎完全無菌。

It's so significant,

它非常特別，

it has a special name, meconium. 用詞

還有一個專門的名稱：胎便。

Now, I will spare you any pictures, 片語搭配

我就不拿圖片嚇大家了，

but if you ever want to call someone a poop head,

但如果你哪天想罵某人是「大便腦袋」，

try instead calling them a meconium head.

不妨改叫他「胎便腦袋」。

It's like a poop head, but with no experience. 慣用語

就像「大便腦袋」，只不過毫無經驗。

As soon as you leave your mother, 文法

你一離開母體，

you begin collecting microorganisms inside your digestive system.

消化系統裡就開始聚集微生物。

In fact, within the first 5 to 10 minutes of being born,

事實上，在出生後的頭5到10分鐘內，

the gut flora that you have are almost exactly equivalent

你的腸道菌叢幾乎完全等同於

to the microorganisms living in your mother's birth canal.

你母親產道裡的微生物。

Now, later, these microorganisms come from your environment,

之後，這些微生物會來自你周遭的環境，

especially from what you eat, milk, or formula.

特別是你吃的東西、母乳或配方奶。

This early in your life,

在生命這麼早的階段，

microorganisms train your immune system to not attack them. 片語搭配

微生物會訓練你的免疫系統，讓它不要攻擊它們。

And so, within the first 2 or 3 months of your life,

因此，在你出生後的頭兩三個月裡，

whatever microorganisms are there have largely established themselves 文法

當時存在的微生物大多都會站穩腳步，

as the exact colonial makeup of your gut flora

形成你腸道菌叢確切的群落組成，

for your entire life.

並伴隨你一輩子。

That's all cool, but how loud can a fart get? 表達脈絡

這些都很酷，但屁到底能有多大聲？

Well, the Guinness Book of World Records doesn't know.

這個嘛，《金氏世界紀錄》也不知道。

In fact, there are a lot of records it doesn't keep,

事實上，它有很多紀錄都不收，

some of which it doesn't keep because they're dangerous. 文法

有些是因為太危險才不收錄。

For instance, speed drinking.

例如速飲比賽。

It's possible to open up your throat

人確實可以把喉嚨完全打開，

and literally pour a liquid straight down your esophagus into your belly.

直接把液體沿著食道灌進肚子裡。

But it is really dangerous and should never be done by anybody.

但這極度危險，任何人都絕對不該嘗試。

Now, burping, they do have records of. 文法

不過，打嗝倒是有紀錄。

The world record for the largest burp belongs to Paul Hunn from the United Kingdom,

最大聲嗝的世界紀錄由英國的Paul Hunn保持，

whose burp registered 109.9 dB, 用詞

他的嗝測得109.9分貝，

about as loud as a car horn. 文法

差不多跟汽車喇叭一樣大聲。

Oh, and also, many of these microorganisms that live inside your gut

另外，住在你腸道裡的許多微生物

and digest food and make farts smell bad

會消化食物，讓屁變臭，

also create gases that are flammable.

同時也會產生可燃氣體。

We've all seen this, and it is very, very true.

這種場面我們都看過，而且真的千真萬確。

The MythBusters even did an episode where they proved that farts can be lit on fire, 片語搭配

《流言終結者》甚至拍過一集，證明屁真的可以被點燃，

but the episode was deemed too gross and never aired. 用詞

但那集被認為太噁心，最後沒有播出。

Another thing you should know about farts is that when you hold them in, 片語動詞

關於屁，你還該知道一件事：當你憋屁時，

many of the gases inside them will get reabsorbed back into your bloodstream 片語搭配

裡面的許多氣體會被重新吸收進血液，

through the intestinal lumen.

這個過程會經由腸腔進行。

Now, the smelly stinky stuff doesn't travel this way,

不過，那些臭味物質不會循這條路徑移動，

but the nutrient stuff like oxygen will.

但氧氣等有用的成分會。

And the bloodstream brings these gases back to the lungs

血液會把這些氣體帶回肺部，

where you exhale them.

再由你呼出去。

So, if you hold in your farts a lot,

所以，如果你常常憋屁，

you, in a way, will have literal fart breath. 語氣意圖

某種意義上，你呼出的氣就真的成了「屁氣」。

The Fitzroy River turtle does one better. 慣用語

菲茨羅伊河龜更勝一籌。

It can do what I like to call a reverse fart. 語氣意圖

牠能做到一件我喜歡稱為「反向放屁」的事。

Because it spends so much time underwater,

因為牠大部分時間都待在水下，

it's developed a way to breathe through its butt. 片語搭配

所以演化出用屁股呼吸的方法。

It actually can get up to 68% of the oxygen it needs

牠所需的氧氣中，實際上多達68%

by simply opening up that cavity

都可以只靠打開那個腔室，

and getting oxygen from the water.

從水中取得。

Finally, I want to leave you with the art of the fart. 表達脈絡

最後，我想用「屁的藝術」為今天收尾。

The way your farts sound is determined 片語搭配

你的屁聲聽起來如何，

by their speed and the shape of their exit.

取決於氣體的速度和出口的形狀。

But a select few can not only make themselves create flatus on command, 講解

但極少數人不只能隨心所欲地放屁，

but can also modulate the pitch and tone of their farts. 片語搭配

還能調整屁的音高和音色。

These people are known as flatulists. 片語搭配

這些人被稱為「放屁表演家」。

And one of the most famous right now is Mr. Methane.

當今最有名的人物之一就是Mr. Methane。

Amazing, right?

很厲害，對吧？

Well, now that we've talked about farts, 表達脈絡

好了，既然屁聊完了，

let's move on to outer space on youtube.com/spacelab.

接著就到youtube.com/spacelab聊聊外太空吧。

Go over there now,

現在就過去，

and you can ask me any question about outer space that you want.

你可以問我任何想問的外太空問題。

And every week I will answer three of them.

每週我都會回答其中三個。

So, what are you waiting for? 語氣意圖

還等什麼呢？

Go check that out. 片語動詞

快去看看吧。

And as always, thanks for watching.

一如往常，感謝收看。