極限慢動作下的聲懸浮 - Smarter Every Day 134：英語精讀講義

Hey, it's me Destin.

嘿，我是 Destin。

Welcome back to Smarter Every Day.

歡迎回到 Smarter Every Day。

I am in Chicago.

我現在在芝加哥。

Anthony picked me up in his awesome Mustang and told me to come to this building 片語動詞

Anthony 開著他超酷的 Mustang 來接我，並叫我來這棟大樓，

because we're going to film acoustic levitation.

因為我們要拍攝聲懸浮。

What is this?

這是什麼？

This is an acoustic levitator.

這是一個聲懸浮器。

Uh it's single axis,

呃，它是單軸的，

which means that we only control things on one axis here. 表達脈絡

意思是這裡只能在一個軸上控制物體。

Um so we have two horns or transducers.

嗯，我們有兩個號角或換能器。

Um Any time I see an oscilloscope I get excited. 文法

嗯，每次我看到示波器都會很興奮。

So am I gonna hear it on the camera?

那麼能在攝影機裡聽到它的聲音嗎？

You'll so the main frequency we're using again is 22kHz

你會的，我們主要使用的頻率依然是 22kHz，

which is higher than human hearing.

這超出了人類的聽覺範圍。

Um what you'll be hearing are sub-harmonic around 17-18kHz

嗯，你能聽到的將是 17-18kHz 左右的次諧波。

But I can just put a low pass filter on the audio 用詞

但我可以在音訊上加一個低通濾波器，

and I can I'm guessing that you cut it out, 片語動詞

我想你們會把它剪掉的，

yeah. Okay.

是的。好的。

Turn it up 片語動詞

調高一點，

and on the oscilloscope you'll see

你會在示波器上看到，

the two waves from each of the two horns.

兩個號角各自產生的聲波。

Well, let's stinking levitate something, dude. 用詞

好了，老兄，我們趕緊來懸浮點什麼吧。

So that's just a Styrofoam ball.

這是一個保麗龍球。

And the spoon has all those slots and

湯匙上有很多縫隙，

so the sound passes right through it.

聲音可以直接穿過去。

No way. 語氣意圖

不是吧。

And then I can just...

然後我只需……

And by sound you mean pressure? 語氣意圖

你說的聲音是指壓力嗎？

Yeah, the sound waves, which are pressure waves.

對，聲波，也就是壓力波。

I mean,

我的意思是，

but you can see the wave length spacing basically between these.

你基本上可以看到它們之間的波長間距。

That's stinking awesome.

真是太棒了。

You may have seen sound drawn like this,

你可能見過像這樣畫出來的聲音，

but it's a bit too simplified. 文法

但這有點過於簡化了。

A real sound wave actually looks like this.

真正的聲波其實長這樣。

The bright parts are the higher pressure

較亮的部分是高壓，

and the darker parts are the low pressure.

較暗的部分是低壓。

These ripples move along at the speed of sound.

這些漣漪以音速移動。

When you have two identical sound waves and you line them up just right, 講解

當你有兩個相同的聲波，且將它們完全對齊時，

they no longer act like waves moving across the room. 文法

它們就不再像穿過房間的聲波那樣運動了。

If you have a wave coming from this side

如果有一個波從這邊過來，

and another wave coming from the other side,

另一個波從另一邊過來，

they become what's called a standing wave. 講解

它們就會變成所謂的「駐波」。

You get a spot right here where there's a pressure flipping on and off

在這裡你會得到一個壓力不斷開、關翻轉的點，

and a spot right here where the pressure isn't changing at all.

而在這裡你會得到一個壓力完全沒有變化的點。

There's no oscillation.

沒有任何振盪。

If you flip this thing upright and then you put something tiny right inside that little pocket,

如果你把這玩意豎起來，然後在這個小空隙裡放進一個微小的物體，

you can use that air pressure to bump something up against the force of gravity.

你就可以利用氣壓把物體往上推，以對抗重力。

So it ends up looking like this Ping-Pong paddle. 片語動詞

所以它最後看起來就像這個桌球拍一樣。

The particle wants to drop,

粒子想要掉落，

but it keeps getting knocked back up by the high pressure wave below it. 文法

但它不斷被下方的高壓波推回去。

And that is acoustic levitation.

這就是聲懸浮。

So if it works with foam,

如果它對泡棉有效，

it should work with water, right?

那對水也應該有效吧？

Anthony uses a syringe to balance little drops of water on top of that oscillating wave.

Anthony 用注射器將小水滴平衡在振盪波的頂部。

Just like the Ping-Pong ball,

就像桌球一樣，

you can see it bouncing up and down.

你可以看到它在上下跳動。

Look at the one on the bottom

看看底部的那個，

bouncing up and down trying to find its spot.

它在上下跳動尋找自己的位置。

Another cool thing is the fact that if I make the water drops too big,

另一件很酷的事情是，如果我把水滴弄得太大，

they always seem to explode.

它們似乎總是會爆炸。

Why would it do that? 語氣意圖

為什麼會這樣？

It happens just a little too fast to see with the naked eye. 講解

它發生得有點太快了，肉眼看不清。

I flew home wishing I had some way of bringing together the acoustic levitation machine 講解

飛回家後，我希望有辦法能把這台聲懸浮機

and a high-speed camera.

和高速攝影機結合起來。

10 months went by. 片語動詞

10 個月過去了。

I had no way of doing this, 片語搭配

我沒有辦法做到，

but then I got a call from Ford.

但後來我接到了 Ford 的電話。

They wanted to know if I could do any sound experiments 文法

他們想知道我能否在好萊塢的

on American Idol out in Hollywood.

《美國偶像》裡做一些聲音實驗。

We have 2 hours with the most amazing setup I've ever worked with, 文法

我們有兩個小時的時間，使用我所合作過最棒的設備：

an ultrasonic levitation device

一台超聲波懸浮裝置，

and two really fast high-speed cameras.

和兩台真正快的高速攝影機。

We're gonna do 20,000 frames per second with the V2511

我們將用 V2511 拍攝每秒 20,000 幀，

and we're gonna do 7500 frames per second with the V711.

並用 V711 拍攝每秒 7500 幀。

I didn't want to just make a TV segment. 表達脈絡

我不想只做一個電視片段。

I actually wanted to hang out with these guys 片語動詞

我其實想和這些傢伙待在一起，

and teach them something new about sound.

教他們一些關於聲音的新知識。

Hi, I'm Jax.

嗨，我是 Jax。

I'm Rayvon.

我是 Rayvon。

I'm Clark.

我是 Clark。

I'm Tyanna.

我是 Tyanna。

I'm Nick.

我是 Nick。

All right,

好了，

so we're not gonna pretend like these guys don't know what's up 講解

我們就不假裝這些傢伙不知道怎麼回事了，

cuz we've already done a segment

因為我們已經錄過一段了，

and they're actually you know how this works now, right?

他們實際上已經知道這是怎麼運作的了，對吧？

Yeah, okay.

是的，沒錯。

Come over here and let's show everybody how it works.

過來這邊，我們給大家展示一下這是怎麼運作的。

It looks to me like just an amp. 語氣意圖

在我看來，它就像個擴音器。

Okay.

好的。

And when I turn up the amplitude,

當我調大振幅時，

the sound waves through the horns

通過號角傳出的聲波

will come down against each other

會自上而下相互碰撞，

and it'll make a column

它會形成一個柱狀空間，

where you can actually suspend liquid or you know things of physical

你可以在那裡懸浮液體，或者說實體物質。

That's right.

沒錯。

That's right.

沒錯。

Did he get it right?

他說對了嗎？

I think he did.

我覺得對了。

There's an equation that dictates how big a raindrop can be, okay? 用詞

有個方程式決定了雨滴能有多大，好嗎？

So the pressure that's on the inside of the drop

水滴內部的壓力，

is determined by two times the surface tension 講解

由兩倍的表面張力

divided by the radius.

除以半徑來決定。

If the drop gets too big,

如果水滴變得太大，

what happens?

會發生什麼事？

It explodes.

它會爆炸。

It explodes.

它會爆炸。

We're recording high-speed video of these drops that we're levitating

我們正在錄製正在懸浮的水滴的高速影片，

and then we're ramping up the amplitude, 片語動詞

然後我們增加振幅，

which is the same as changing the pressure, right?

這就等同於改變壓力，對吧？

So once we do that,

所以一旦我們這麼做，

the pressure gets so great 文法

壓力變得如此之大，

that the surface tension can't hold the drop together any more 片語動詞

以至於表面張力再也無法將水滴凝聚在一起，

and then it just ruptures.

然後它就破裂了。

It overcomes that internal pressure

它克服了內部壓力，

and you get an explosion.

於是就爆炸了。

All right,

好了，

I hope you enjoyed this episode of Smarter Every Day.

希望你喜歡這期 Smarter Every Day。

I'm not obligated to say anything about any product, 用詞

我沒有義務為任何產品說好話，

but Ford was awesome.

但是 Ford 真的很棒。

Seriously, they let me do awesome science on national TV

說真的，他們讓我在國家電視台上展示很棒的科學，

and they made all that happen.

是他們促成了這一切。

So thank you very much, Ford.

所以非常感謝你，Ford。

I

我

appreciate that.

真的很感激。

Also, I did not have to get a Ford Focus at the airport, 文法

還有，我本不一定要在機場租一輛 Ford Focus，

but I wanted to check it out 片語動詞

但我想試一下，

and I'm happy with it.

而且我很滿意。

So, there you go.

好了，就是這樣。

Please support Ford.

請支持 Ford。

They supported Smarter Every Day.

他們支持了 Smarter Every Day。

I don't have to say that.

我不一定要說這些，

I hope you believe me.

但希望你們相信我。

Also,

還有，

please consider subscribing if you learned something

如果你學到了新知識，請考慮訂閱我們，

or checking us out at Smarter Every Day on Patreon.

或者在 Patreon 上的 Smarter Every Day 看看我們。

I am Destin.

我是 Destin。

You're getting smarter every day.

你正在每天變得更聰明。

Have a good one. 語氣意圖

祝你有美好的一天。

I'm with you.

我同意。

Okay,

好了，

teach me something else.

再教我點別的吧。

Um so one kind of cool thing...

嗯，有件挺酷的事……

Oh shit.

噢，糟了。

What could you be possibly doing that's more important than acoustic levitation? 語氣意圖

你到底在幹嘛，能比聲懸浮還重要？