If superpowers were real: Invisibility - Joy Lin

1,436,788 views ใƒป 2013-06-27

TED-Ed


ืื ื ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ืœืžื˜ื” ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ.

ืชืจื’ื•ื: Ido Dekkers ืขืจื™ื›ื”: Zeeva Livshitz
00:14
Wouldn't it be great if we could be
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ื–ื” ืœื ื”ื™ื” ื ืคืœื ืื ื™ื›ื•ืœื ื• ืœื”ื™ื•ืช
00:17
invisible?
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ื‘ืœืชื™ ื ืจืื™ื?
00:18
Ha, right?
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ื”ื, ื ื›ื•ืŸ?
00:19
I mean, we could spy on people without being noticed
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ืื ื™ ืžืชื›ื•ื•ื ืช, ื ื•ื›ืœ ืœืจื’ืœ ืขืœ ืื ืฉื™ื ื‘ืœื™ ืฉื™ืฉื™ืžื• ืœื‘ ืืœื™ื ื•
00:21
and do whatever we want
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ื•ืœืขืฉื•ืช ืžื” ืฉื ืจืฆื”
00:22
without being held responsible.
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ื‘ืœื™ ืœื”ื™ื•ืช ืื—ืจืื™ื.
00:25
Now, magicians have figured out
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ืขื›ืฉื™ื•, ืงื•ืกืžื™ื ื”ื‘ื™ื ื•
00:27
how to utilize full-sized mirrors to bend light
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ืื™ืš ืœื”ืฉืชืžืฉ ื‘ืžืจืื•ืช ื‘ื’ื•ื“ืœ ืžืœื ื›ื“ื™ ืœืขืงื ืืช ื”ืื•ืจ
00:29
in order to create disappearing illusions.
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ื‘ืžื˜ืจื” ืœื™ืฆื•ืจ ืืฉืœื™ื™ืช ื”ืขืœืžื•ืช.
00:34
Scientists have created metamaterials
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ืžื“ืขื ื™ื ื™ืฆืจื• ืžื˜ื-ื—ื•ืžืจื™ื
00:36
to guide rays of light
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ื›ื“ื™ ืœื”ื ื—ื•ืช ืงืจื ื™ ืื•ืจ
00:37
around tiny, two-dimensional objects.
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ืกื‘ื™ื‘ ืขืฆืžื™ื ื“ื• ืžื™ืžื“ื™ื™ื ื–ืขื™ืจื™ื.
00:40
Cameras can also film what is behind you
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ืžืฆืœืžื•ืช ื™ื›ื•ืœื•ืช ื’ื ืœืฆืœื ืžื” ืฉืžืื—ื•ืจื™ื›ื
00:43
and project the image
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00:43
so you appear invisible from the front.
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ื•ืœื”ืงืจื™ืŸ ืืช ื”ืชืžื•ื ื”
ื›ืš ืฉืชืจืื• ื‘ืœืชื™ ื ืจืื™ื ืžืงื“ื™ืžื”.
00:47
However, none of these options
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ืขื ื–ืืช, ืืฃ ืื—ืช ืžื”ืืคืฉืจื•ื™ื•ืช ื”ืืœื”
00:49
can make an object as large as a person
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ืœื ื™ื›ื•ืœื” ืœื”ืคื•ืš ืขืฆื ื‘ื’ื•ื“ืœ ืฉืœ ืื“ื
00:51
appear invisible for all angles and distances
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ืœื‘ืœืชื™ ื ืจืื” ืžื›ืœ ื”ื–ื•ื™ื•ืช ื•ื›ืœ ื”ืžืจื—ืงื™ื
00:54
while its moving.
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ื‘ืชื ื•ืขื”.
00:55
But if you are truly invisible,
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ืื‘ืœ ืื ืืชื ื‘ืืžืช ื‘ืœืชื™ ื ืจืื™ื,
00:57
as in from within,
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ืžืžืฉ ืžื‘ืคื ื™ื,
00:59
here are a few problems
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ื”ื ื” ื›ืžื” ื‘ืขื™ื•ืช
01:00
you may not have thought about before.
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ืฉืื•ืœื™ ืœื ื—ืฉื‘ืชื ืขืœื™ื”ืŸ ืœืคื ื™ ื›ืŸ.
01:03
To move around undetected by other people,
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ื›ื“ื™ ืœื ื•ืข ื‘ืœื™ ืฉืื ืฉื™ื ืื—ืจื™ื ื™ื–ื”ื• ืืชื›ื,
01:06
you would have to be totally naked.
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ืืชื ืชืฆื˜ืจื›ื• ืœื”ื™ื•ืช ืขืจื•ืžื™ื ืœื’ืžืจื™.
01:09
Even if it's freezing outside!
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ืืคื™ืœื• ื›ืฉืงืคื•ื ื‘ื—ื•ืฅ!
01:13
You can't carry anything,
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ืืชื ืœื ื™ื›ื•ืœื™ื ืœืงื—ืช ืฉื•ื ื“ื‘ืจ,
01:14
including your wallet and keys,
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ื›ื•ืœืœ ื”ืืจื ืง ื•ื”ืžืคืชื—ื•ืช,
01:16
otherwise people would just see
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ืื—ืจืช ืื ืฉื™ื ื™ืจืื• ืจืง
01:18
your wallet and keys floating around.
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ืืช ื”ืืจื ืง ื•ื”ืžืคืชื—ื•ืช ืฉืœื›ื ืฆืคื™ื ื‘ืกื‘ื™ื‘ื”.
01:20
Drivers and people on the street can't see you either,
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ื ื”ื’ื™ื ื•ืื ืฉื™ื ื‘ืจื—ื•ื‘ ืœื ื™ื•ื›ืœื• ืœืจืื•ืช ืืชื›ื,
01:22
therefore they can and will run into you at some point.
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ืœื›ืŸ ื”ื ื™ืชื ื’ืฉื• ื‘ื›ื ื‘ื ืงื•ื“ื” ื›ืœืฉื”ื™.
01:27
Oh, and you better not wear any perfume
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ืื•ื”, ื•ื›ื“ืื™ ืฉืœื ืชืชื‘ืฉืžื•
01:30
or make any noise breathing,
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ืื• ืฉืชืขืฉื• ืจืขืฉื™ื ืฉืœ ื ืฉื™ืžื”,
01:32
otherwise they'll know you're there.
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ืื—ืจืช ื”ื ื™ื“ืขื• ืฉืืชื ืฉื.
01:38
And, just because you start off invisible,
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ื•ืจืง ื‘ื’ืœืœ ืฉื”ืชื—ืœืชื ื‘ืœืชื™ ื ืจืื™ื,
ืœื ืื•ืžืจ ืฉืชืฉืืจื• ื›ื›ื”.
01:40
doesn't mean you'll stay that way.
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01:42
What if someone accidentally spills
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ืžื” ืื ืžื™ืฉื”ื• ื‘ื˜ืขื•ืช ื™ืฉืคื•ืš ืขืœื™ื›ื
01:43
scolding hot coffee on you?
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ืงืคื” ืจื•ืชื—?
01:46
And what if it rains?
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ื•ืžื” ืื ื™ืจื“ ื’ืฉื?
01:50
But if you think only liquid can make you visible,
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ืื‘ืœ ืื ืืชื ื—ื•ืฉื‘ื™ื ืฉืจืง ื ื•ื–ืœื™ื ื™ื›ื•ืœื™ื ืœื”ืคื•ืš ืืชื›ื ืœื ืจืื™ื,
01:54
you're wrong.
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ืืชื ื˜ื•ืขื™ื.
01:55
Dust consists of dead skin cells from humans,
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ืื‘ืง ืžื›ื™ืœ ืชืื™ ืขื•ืจ ืžืชื™ื ืžืื ืฉื™ื,
01:58
soil particles,
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01:58
and fibers from clothes made from cotton
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ื—ืœืงื™ืงื™ ืื“ืžื”,
ื•ืกื™ื‘ื™ื ืžื‘ื’ื“ื™ื ืฉืขืฉื•ื™ื™ื ืžื›ื•ืชื ื”
02:01
and other materials.
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ื•ื—ื•ืžืจื™ื ืื—ืจื™ื.
02:02
Dust sticks to the moisture on our skin when we sweat
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ืื‘ืง ื ื“ื‘ืง ืœืœื—ื•ืช ืขืœ ืขื•ืจื™ื ื• ื›ืฉืื ื—ื ื• ืžื–ื™ืขื™ื
02:05
and the tiny hairs on our skin when we are dry.
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ื•ื”ืฉืขืจื•ืช ื”ืงื˜ื ื•ืช ืขืœ ืขื•ืจื™ื ื• ื›ืฉืื ื—ื ื• ื™ื‘ืฉื™ื.
02:08
So, even if you are invisible,
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ืื–, ืืคื™ืœื• ืื ืืชื ื‘ืœืชื™ ื ืจืื™ื,
02:11
dust would still land on every part of you.
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ืื‘ืง ืขื“ื™ื™ืŸ ื™ื ื—ืช ืขืœ ื›ืœ ื—ืœืง ืฉืœื›ื.
02:13
We usually don't notice the dust on our skin
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ืื ื—ื ื• ื‘ื“ืจืš ื›ืœืœ ืœื ืžื‘ื—ื™ื ื™ื ื‘ืื‘ืง ืขืœ ื”ืขื•ืจ
02:15
because we can't see a thin layer of dust
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ืžืคื ื™ ืฉืื ื—ื ื• ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช ืฉื›ื‘ื” ื“ืงื” ืฉืœ ืื‘ืง
02:17
on top of our skin color.
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ืขืœ ืฆื‘ืข ื”ืขื•ืจ ืฉืœื ื•.
02:18
But, if you're invisible,
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ืื‘ืœ, ืื ืืชื ื‘ืœืชื™ ื ืจืื™ื,
02:20
people would see a human-shaped blob of dust
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ืื ืฉื™ื ื™ืจืื• ืฆื•ืจื•ืช ืฉืœ ืื ืฉื™ื ื‘ืื‘ืง
02:22
walking around with extremely dirty soles.
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ืžืชื”ืœื›ื•ืช ืขื ื›ืคื•ืช ืจื’ืœื™ื™ื ืžืžืฉ ืžืœื•ื›ืœื›ื•ืช.
02:27
Gross!
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ืžื’ืขื™ืœ!
02:28
What do you think the world looks like
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ืื™ืš ืืชื ื—ื•ืฉื‘ื™ื ืฉื”ืขื•ืœื ื™ืจืื”
02:29
if you are invisible?
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ืื ื”ื™ื™ืชื ื‘ืœืชื™ ื ืจืื™ื?
02:30
Well, the answer is nothing.
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ื•ื‘ื›ืŸ ,ื”ืชืฉื•ื‘ื” ื”ื™ื ื›ืœื•ื.
02:33
The reason you can't see in the dark
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ื”ืกื™ื‘ื” ืฉืืชื ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช ื‘ื—ืฉื›ื”
02:34
is because there is no light.
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ื”ื™ื ื‘ื’ืœืœ ืฉืื™ืŸ ืื•ืจ.
02:36
To see an apple,
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ื›ื“ื™ ืœืจืื•ืช ืชืคื•ื—,
02:37
light has to hit the apple
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ืื•ืจ ืฆืจื™ืš ืœืคื’ื•ืข ื‘ืชืคื•ื—
02:38
and return it to your eyes.
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ื•ืœื—ื–ื•ืจ ืœืขื™ื ื™ื›ื.
02:40
Then, the retinas in your eyes
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ืื–, ื”ืจืฉืชื™ืช ื‘ืขื™ื ื™ื›ื
02:41
catch the light reflection for your brain
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ืงื•ืœื˜ืช ืืช ื”ื”ืฉืชืงืคื•ืช ื‘ืฉื‘ื™ืœ ื”ืžื•ื— ืฉืœื›ื
02:43
to interpret into the image of an apple.
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ื›ื“ื™ ืฉื™ืคืจืฉ ืื•ืชื” ืœืชืžื•ื ื” ืฉืœ ืชืคื•ื—.
02:46
If you're invisible,
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ืื ืืชื ื‘ืœืชื™ ื ืจืื™ื,
02:47
then, by definition, light would travel
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ืื–, ื‘ื”ื’ื“ืจื”, ืื•ืจ ื™ืขื‘ื•ืจ
02:49
through you or around you
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ื“ืจื›ื›ื ืื• ืกื‘ื™ื‘ื›ื
02:51
instead of bouncing off you for people to see.
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ื‘ืžืงื•ื ืœื—ื–ื•ืจ ืžื›ื ื›ื“ื™ ืฉืื ืฉื™ื ื™ืจืื•.
02:54
But that means that retinas in your eyes
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ืื‘ืœ ื–ื” ืื•ืžืจ ืฉื”ืจืฉืชื™ื•ืช ื‘ืขื™ื ื™ื›ื
02:56
are not catching the light, either.
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ืœื ืงื•ืœื˜ื•ืช ืื•ืจ, ื’ื ื”ืŸ.
02:58
Therefore, your brain has nothing
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ืœื›ืŸ, ื”ืžื•ื— ืฉืœื›ื ืœื ืžืงื‘ืœ ื›ืœื•ื
02:59
to interpret into an image.
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ืœืคืจืฉ ืœืชืžื•ื ื”.
03:01
Can you see your reflection
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ืืชื ื™ื›ื•ืœื™ื ืœืจืื•ืช ืืช ื”ื”ืฉืชืงืคื•ืช ืฉืœื›ื
03:03
without a mirror to stop the light?
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ื‘ืœื™ ืžืจืื” ืฉืชืขืฆื•ืจ ืืช ื”ืื•ืจ?
03:04
No.
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ืœื.
03:05
So, when you can't be seen by others,
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ืื–, ื›ืฉืื—ืจื™ื ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช ืืชื›ื,
03:07
you also cannot see.
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ืืชื ื’ื ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช.
03:10
Ouch!
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ืืื•ืฆ'!
03:12
Now, have you given any thought
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ืขื›ืฉื™ื•, ื—ืฉื‘ืชื ื’ื
03:13
as of whether the invisibility is permanent?
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ืื ื”ื‘ืœืชื™-ื ืจืื•ืช ื”ื™ื ืงื‘ื•ืขื”?
03:16
If it is, how can you receive medical treatment
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ืื ื”ื™ื ื›ืš, ืื™ืš ืชื•ื›ืœื• ืœืงื‘ืœ ื˜ื™ืคื•ืœ ืจืคื•ืื™
03:18
from a doctor if you're injured?
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ืžืจื•ืคื ืื ืชืคืฆืขื•?
03:20
The doctor wouldn't know
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ื”ืจื•ืคื ืœื ื™ื“ืข
03:21
where to apply ointments or bandages
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ื”ื™ื›ืŸ ืœืžืจื•ื— ืืช ื”ืžืฉื—ื” ืื• ืœื—ื‘ื•ืฉ
03:23
because they cannot access your injury.
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ืžืคื ื™ ืฉื”ื ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช ืืช ื”ืคืฆืข ืฉืœื›ื.
03:27
For that matter, you can't see it either.
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ื‘ืื•ืชื” ื“ืจืš, ื’ื ืืชื ืœื ื™ื›ื•ืœื™ื ืœืจืื•ืช ืื•ืชื•.
03:29
I mean, what if you have an illness or an infection?
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ืื ื™ ืžืชื›ื•ื•ื ืช, ืžื” ืื ื™ืฉ ืœื›ื ืžื—ืœื” ืื• ื–ื™ื”ื•ื?
03:32
How can the doctor diagnose you
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ืื™ืš ื”ืจื•ืคื ื™ื›ื•ืœ ืœืื‘ื—ืŸ ืืชื›ื
03:33
without being able to see the color change or inflammation?
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ื‘ืœื™ ืœื”ื™ื•ืช ืžืกื•ื’ืœ ืœืจืื•ืช ืืช ืฉื™ื ื•ื™ ื”ืฆื‘ืข ืื• ื”ื“ืœืงืช?
03:36
And what if everyone is permanently invisible?
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ื•ืžื” ืื ื›ื•ืœื ื”ื™ื• ื‘ืœืชื™ ื ืจืื™ื ืœืชืžื™ื“?
03:39
Well, think about how boring the world would be
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ื•ื‘ื›ืŸ, ื—ืฉื‘ื• ืขืœ ื›ืžื” ืžืฉืขืžื ื”ืขื•ืœื ื”ื™ื”
ื‘ืœื™ ืœืจืื•ืช ืื ืฉื™ื ื‘ืจื—ื•ื‘,
03:42
without seeing people on the streets,
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03:43
on TV,
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ื‘ื˜ืœื•ื•ื™ื–ื™ื”,
03:44
or at home on your computer
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ืื• ื‘ื‘ื™ืช ืขืœ ื”ืžื—ืฉื‘
03:47
like right now.
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ื›ืžื• ืฉืืชื ืจื•ืื™ื ืขื›ืฉื™ื•.
03:48
It's lonely being invisible.
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ื–ื” ืžืื•ื“ ื‘ื•ื“ื“ ืœื”ื™ื•ืช ื‘ืœืชื™ ื ืจืื”.
03:54
Now, which superpower physics lesson
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ืขื›ืฉื™ื•, ืื™ื–ื” ืฉื™ืขื•ืจ ืคื™ืกื™ืงื” ื‘ื›ื•ื—ื•ืช ืขืœ
03:57
will you explore next?
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ื”ื™ื™ืชื ื—ื•ืงืจื™ื ื”ืœืื”?
03:59
Shifting body size and content,
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ืฉื™ื ื•ื™ ื’ื•ื“ืœ ื’ื•ืฃ ื•ืชื•ื›ืŸ,
04:03
super speed,
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ืžื”ื™ืจื•ืช ืขืœ,
04:05
flight,
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ืžืขื•ืฃ,
04:06
super strength,
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ื›ื•ื— ืขืœ,
04:09
immortality,
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ื—ื™ื™ ื ืฆื—,
04:12
and
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ื•...
04:14
invisibility.
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ื‘ืœืชื™ื™-ื ืจืื•ืช.
ืขืœ ืืชืจ ื–ื”

ืืชืจ ื–ื” ื™ืฆื™ื’ ื‘ืคื ื™ื›ื ืกืจื˜ื•ื ื™ YouTube ื”ืžื•ืขื™ืœื™ื ืœืœื™ืžื•ื“ ืื ื’ืœื™ืช. ืชื•ื›ืœื• ืœืจืื•ืช ืฉื™ืขื•ืจื™ ืื ื’ืœื™ืช ื”ืžื•ืขื‘ืจื™ื ืขืœ ื™ื“ื™ ืžื•ืจื™ื ืžื”ืฉื•ืจื” ื”ืจืืฉื•ื ื” ืžืจื—ื‘ื™ ื”ืขื•ืœื. ืœื—ืฅ ืคืขืžื™ื™ื ืขืœ ื”ื›ืชื•ื‘ื™ื•ืช ื‘ืื ื’ืœื™ืช ื”ืžื•ืฆื’ื•ืช ื‘ื›ืœ ื“ืฃ ื•ื™ื“ืื• ื›ื“ื™ ืœื”ืคืขื™ืœ ืืช ื”ืกืจื˜ื•ืŸ ืžืฉื. ื”ื›ืชื•ื‘ื™ื•ืช ื’ื•ืœืœื•ืช ื‘ืกื ื›ืจื•ืŸ ืขื ื”ืคืขืœืช ื”ื•ื•ื™ื“ืื•. ืื ื™ืฉ ืœืš ื”ืขืจื•ืช ืื• ื‘ืงืฉื•ืช, ืื ื ืฆื•ืจ ืื™ืชื ื• ืงืฉืจ ื‘ืืžืฆืขื•ืช ื˜ื•ืคืก ื™ืฆื™ืจืช ืงืฉืจ ื–ื”.

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