满是污垢的屏幕上有多少卡路里？：英语精读讲义

Hey, Vsauce.

嘿，Vsauce。

Michael here,

我是Michael，

and I am home for the holidays. 短語搭配

我回家过节了。

I'm in my parents' basement using a different camera than usual. 語法

我现在待在父母家的地下室里，用的摄像机也和平常不一样。

But you know what is always different?

不过，你知道什么东西总是不一样吗？

Fingerprints.

指纹。

The palms of our hands and the soles of our feet are weird.

我们的手掌和脚底很奇怪。

They are covered with friction ridges, 用詞

上面布满了摩擦嵴，

which act like the design of a stamp that stamps everything you touch. 表達脈絡

就像印章上的图案一样，会印在你触碰的每件东西上。

Plastic or patent prints are visible to the naked eye. 習語

立体指纹或显性指纹可以直接用肉眼看到。

But even with seemingly clean hands on a seemingly clean surface, 語法

但即使用看似干净的手去摸看似干净的表面，

a fingerprint can be left.

也可能留下指纹。

A latent fingerprint. 用詞

一道潜在指纹。

But what are those made of?

但这些指纹究竟是由什么构成的呢？

Well, by the square millimeter,

嗯，按每平方毫米来看，

they're made out of this.

它们就是由这些东西构成的。

All of this stuff is natural.

这些东西全都是人体自然产生的。

In fact,

事实上，

a lot of it is produced to keep your skin healthy,

其中很多都是人体为了让皮肤保持健康、

waterproof,

防水、

pliable.

柔韧而分泌的。

But touch a surface enough and the gunk can build up. 短語動詞

但只要反复触碰一个表面，污垢就会越积越多。

It's what causes smudges on computer screens and mobile devices.

电脑屏幕和移动设备上的污迹就是这么来的。

Now,

那么，

given that protein contains 4 calories per gram,

已知每克蛋白质含4卡路里，

fat contains 9 calories per gram,

每克脂肪含9卡路里，

and the surface area of the iPhone 5 is 4,400 square millimeters,

而iPhone 5的表面积为4,400平方毫米，

completely licking clean a smudgy iPhone 5 screen

如果把一台沾满污迹的iPhone 5屏幕彻底舔干净，

is gonna give you about 2 calories. 用詞

你大约能摄入2卡路里。

If you were to lick clean 245 smudgy iPhone 5s, 語法

如果你舔干净245台脏兮兮的iPhone 5，

well, that would be the same as eating a Big Mac.

那就相当于吃了一个巨无霸。

But before you run off and get all of your nutrition from smudgy phones, 短語動詞

不过，在你急着跑去靠脏手机补充全部营养之前，

you should know that us humans need a bit more variety than that. 語法

你得知道，我们人类需要的营养可比这丰富一点。

I've always found it interesting that cats and dogs can grow up and live great lives

我一直觉得很有意思：猫狗可以长大，并且活得很好，

eating the exact same food every day.

哪怕它们每天吃的都是一模一样的食物。

Well, what about us humans?

那么，我们人类呢？

What can we eat every day without ever changing it up and be fine? 短語動詞

我们可以每天吃什么、从不换样，却依然没事？

It turns out that there is one type of food 表達脈絡

事实证明，确实有一种食物，

that you could eat every day for the rest of your life 短語搭配

你可以余生每天都吃，

and be fine without ever having something different.

即使从不换别的，也不会有问题。

If you follow @tweetsauce,

如果你关注了@tweetsauce，

you already know what it is.

你已经知道答案是什么了。

The answer is human breast milk.

答案就是人类的母乳。

Whether your ridges loop or arch or whorl is largely genetic, 語法

你的嵴纹是箕形、弓形还是斗形，很大程度上由遗传决定，

but the tiny minutiae of your prints formed while you were developing inside your mother. 用詞

但指纹的细微特征，是你还在母亲体内发育时形成的。

It tells a story about the very specific conditions around the dividing cells 習語

它们讲述了分裂中的细胞周围那些极为具体的环境，

that became your skin.

这些细胞后来变成了你的皮肤。

And for that reason, 表達脈絡

正因如此，

even identical twins who pretty much share the exact same DNA

即使是DNA几乎完全相同的同卵双胞胎，

wind up with different fingerprints. 短語動詞

最终也会拥有不同的指纹。

I could clone you 100 times

我可以把你克隆100次，

and every one of those clones would have a unique set of fingerprints.

而每一个克隆体都会拥有独一无二的一组指纹。

Your skin has two major layers,

皮肤主要分为两层，

the epidermis on the outside, 用詞

外面是表皮，

and the dermis, which is below.

下面则是真皮。

The basal layer of your epidermis creates new skin cells,

表皮的基底层会生成新的皮肤细胞，

which migrate up towards the outside world where they die and flatten out, 短語動詞

这些细胞会向外界方向移动，并在途中死亡、变扁，

forming the protective outermost part of your skin,

形成皮肤最外侧的保护层，

the horny layer, 用詞

也就是角质层，

which means that all day,

这意味着一整天，

every day,

日复一日，

you are covered with and showing off to the entire world

你都被它覆盖，还向全世界炫耀着

your horny layer.

你的角质层。

These outer cells are constantly shed away,

这些外层细胞会不断脱落，

but their arrangement stays the same

但它们的排列方式始终不变，

because their shape is determined by the shape of the basal layer down below. 短語搭配

因为它们的形状由下方基底层的形状决定。

This is why you can superficially and temporarily sandpaper or cut off your fingerprints,

所以，你可以用砂纸磨掉或割掉表层指纹，让它暂时消失，

but they'll still grow back the way they were before. 短語動詞

但它仍会按原来的样子重新长出来。

But why do we have fingerprints in the first place? 短語搭配

可我们为什么会有指纹呢？

I mean,

我是说，

not all mammals have friction ridges.

并非所有哺乳动物都有摩擦嵴。

Is this some sort of cruel joke the universe made

难道这是宇宙开的某种残酷玩笑，

to make it more difficult for us humans to get away with crimes? 短語動詞

就是为了让我们人类犯罪后更难逃脱惩罚吗？

Probably not.

大概不是。

The most likely answer is twofold.

最有可能的答案包含两个方面。

First of all,

首先，

it has been shown that friction ridges allow us to sense subtle textures 短語搭配

研究表明，摩擦嵴能让我们感知细微纹理的能力

100 times better than if we didn't have them. 語法

提升到没有它们时的100倍。

And because fingerprints loop and arch and swirl in different directions,

而且，指纹的环形、弓形和旋涡纹路朝向各不相同，

all it takes is one simple touch for us to detect a subtle texture moving in any direction. 語法

我们只需轻轻一触，就能察觉朝任何方向移动的细微纹理。

It's also been shown that having friction ridges allows mammals like us primates, koalas,

研究还表明，摩擦嵴能让我们这类哺乳动物，比如灵长类、考拉、

the North American fisher, 文化背景

北美渔貂等，

to better climb and grasp wet stuff.

更擅长攀爬和抓握湿滑的东西。

Even though no two fingerprints are exactly the same, 語法

尽管世上没有两枚指纹完全相同，

the methods we have for matching fingerprints aren't always perfect.

但我们的指纹比对方法并不总是万无一失。

There are plenty of different ways to model fingerprints

指纹建模有许多不同的方法，

and each one is calculated a different probability of a false match. 用詞

每种方法算出的误匹配概率都不一样。

But if you wanna commit a crime,

不过，如果你想犯罪，

it's best to just avoid fingerprints altogether.

最好还是彻底避开指纹这个问题。

How about hiring someone with adermatoglyphia? 語氣意圖

雇一个患有无皮纹症的人怎么样？

A few skin conditions can cause the disappearance of fingerprints,

有几种皮肤疾病会让指纹消失，

but adermatoglyphia is a genetic one that has no other side effects. 用詞

但无皮纹症是一种没有其他副作用的遗传病。

But it's rare.

不过它很罕见。

Only four extended families on Earth are known to have the condition.

据我们所知，全球只有四个大家族有这种病。

But if you wanna avoid leaving fingerprints

但如果你不想留下指纹，

and can't find somebody with adermatoglyphia,

又找不到患有无皮纹症的人，

don't worry,

别担心，

just find someone who hasn't gone through puberty yet. 短語搭配

只要找个还没进入青春期的人就行。

Sure,

当然，

kids might snot and slobber all over stuff,

小孩可能会把鼻涕和口水蹭得到处都是，

but they carry far less heavy waxy oil on their skin. 語法

但他们皮肤上的厚重蜡状油脂要少得多。

And for this reason,

正因如此，

the fingerprints of a child will disappear,

孩子留下的指纹会消失、

evaporate,

蒸发，

much more quickly than those of an adult.

速度比成年人的指纹快得多。

A child's fingerprints can evaporate in only a few hours.

孩子的指纹只需几个小时就能蒸发。

So,

所以，

use kids to commit your crimes. 語氣意圖

就让孩子帮你犯罪吧。

And as always,

一如既往，

thanks for watching.

感谢观看。