invisible?

那不是超棒的嗎？

Ha, right?

哈，不是嗎？

I mean, we could spy on people without being noticed

我們偷窺別人不會被發現

and do whatever we want

也可以為所欲為

without being held responsible.

卻不用負什麼責任

Now, magicians have figured out

現在，魔術師已經知道

how to utilize full-sized mirrors to bend light

如何利用全身鏡折射光線

in order to create disappearing illusions.

製造出隱形的假象

Scientists have created metamaterials

科學家製造出超材料

to guide rays of light

能引導光線

around tiny, two-dimensional objects.

繞過微細的 2D 物體

Cameras can also film what is behind you

照相機也可以拍攝你背後的景象

and project the image

投射出影像

so you appear invisible from the front.

如此一來，你就像隱形了一樣

However, none of these options

然而，這些方式

can make an object as large as a person

都沒辦法讓一個真人大小的物體

appear invisible for all angles and distances

在移動的情況下

while its moving.

從所有角度和距離看 都保持隱形

But if you are truly invisible,

即使你真的做到

as in from within,

從內到外都隱形

here are a few problems

這裡還有一些問題

you may not have thought about before.

你之前可能沒列入考慮

To move around undetected by other people,

要在別人無法察覺的情況下行動

you would have to be totally naked.

你必須完全裸體

Even if it's freezing outside!

就算外面天寒地凍

You can't carry anything,

你也不能攜帶任何東西

including your wallet and keys,

連你的錢包和鑰匙都不能帶

otherwise people would just see

否則人們就會只看到

your wallet and keys floating around.

你的錢包和鑰匙在空中飄浮移動

Drivers and people on the street can't see you either,

路上的駕駛和行人也看不到你

therefore they can and will run into you at some point.

他們可能會直接撞上你

Oh, and you better not wear any perfume

喔，你最好別用任何香水

or make any noise breathing,

呼吸也不能出聲

otherwise they'll know you're there.

否則人們會注意到你的存在

And, just because you start off invisible,

而且就算你真的開始隱形

doesn't mean you'll stay that way.

也不表示你可以一直如此

What if someone accidentally spills

假使有人不小心

scolding hot coffee on you?

把熱咖啡潑到你身上？

And what if it rains?

又或是下起雨了？

But if you think only liquid can make you visible,

如果你以為只有液體會讓你現形

you're wrong.

那你可就錯了

Dust consists of dead skin cells from humans,

灰塵包含人體代謝的皮膚細胞

soil particles,

土壤顆粒

and fibers from clothes made from cotton

衣服上的棉絮纖維

and other materials.

以及其它材質

Dust sticks to the moisture on our skin when we sweat

我們流汗時 灰塵會附著在潮濕的皮膚上

and the tiny hairs on our skin when we are dry.

而乾燥時灰塵會附在毛髮上

So, even if you are invisible,

所以就算隱形了

dust would still land on every part of you.

灰塵還是會落在你全身上下

We usually don't notice the dust on our skin

我們通常不會注意到皮膚上的灰塵

because we can't see a thin layer of dust

是因為我們有膚色為底

on top of our skin color.

所以看不到有薄薄的灰塵覆蓋

But, if you're invisible,

但如果隱形了

people would see a human-shaped blob of dust

大家就會看到一個覆滿灰塵的人型

walking around with extremely dirty soles.

到處走動還留下超髒的腳印

Gross!

太噁心了！

What do you think the world looks like

你有沒有想過當你隱形的時候

if you are invisible?

這世界看起來是什麼樣子？

Well, the answer is nothing.

答案是什麼都沒有

The reason you can't see in the dark

你在黑暗中看不到東西

is because there is no light.

是因為沒有光線

To see an apple,

你要能看到一個蘋果

light has to hit the apple

得要有光線照到這個蘋果

and return it to your eyes.

再回到你的眼睛

Then, the retinas in your eyes

然後你眼睛裡的視網膜

catch the light reflection for your brain

會將這光線反射到你的腦中

to interpret into the image of an apple.

轉譯為一個蘋果的影像

If you're invisible,

如果你隱形了

then, by definition, light would travel

在這定義下

through you or around you

光線會穿越你，或是繞過你

instead of bouncing off you for people to see.

並不會有任何反射讓人們看到你

But that means that retinas in your eyes

但這代表你的視網膜

are not catching the light, either.

也無法捕捉到任何光線

Therefore, your brain has nothing

所以你的腦不會收到任何訊息

to interpret into an image.

能被轉譯為影像

Can you see your reflection

如果沒有鏡子阻擋光線前進

without a mirror to stop the light?

你能看到你自己的影像嗎？

No.

不能

So, when you can't be seen by others,

所以當你不能被其他人看到時

you also cannot see.

你自己也看不到

Ouch!

哎喲！

Now, have you given any thought

你有想過

as of whether the invisibility is permanent?

要不要永遠隱形嗎？

If it is, how can you receive medical treatment

如果永遠隱形，哪天你受傷了

from a doctor if you're injured?

醫生要怎麼為你治療？

The doctor wouldn't know

醫生無法知道

where to apply ointments or bandages

要在哪裡塗藥膏或是上繃帶

because they cannot access your injury.

因為他們看不到你的傷口

For that matter, you can't see it either.

而且連你自己也看不到啊

I mean, what if you have an illness or an infection?

如果你生病或是感染了

How can the doctor diagnose you

醫生看不到顏色的改變或是發炎的情況

without being able to see the color change or inflammation?

要怎麼幫你診斷？

And what if everyone is permanently invisible?

假如每個人都永遠隱形了呢？

Well, think about how boring the world would be

你想想這世界會有多無趣

without seeing people on the streets,

看不到任何人在街上

on TV,

在電視裡

or at home on your computer

或者是在家裡的電腦上

like right now.

就像現在一樣

It's lonely being invisible.

隱形是很寂寞的

Now, which superpower physics lesson

接下來，你想探索

will you explore next?

哪個超能力物理學課程？

Shifting body size and content,

改變身體大小和成分？

super speed,

超高速？

flight,

飛行能力？

super strength,

超級大力士？

immortality,

永生不死？

and

或者

invisibility.

隱形力