Hey, it's me Destin. Welcome back to Smarter Every Day. So today I'm in California, and I have the great privilege of introducing the MAN, Alan Sailer.
嘿，是我Destin。歡迎回到Smarter Every Day。所以今天我在加州，而且我很榮幸跟你介紹這個人：Alan Sailer。
Hello.
哈囉。
Alan Sailer is, if you don't know, one of the best high speed photographers that currently does the art. So I'm here in his garden, back behind his house, and we're going to basically study explosions underwater with some firecrackers.
Alan Sailer是，如果你不知道，他是現今業界最棒的高速攝影師。所以我現在在他的花園裡面，就在他的房子後面，而我們基本上要用一些爆竹來研究水底爆炸。
You typically do it with the high speed photography method right?
你一般都是用高速攝影的方式對嗎？
Yeah, it's just an instant...instant of detonation, and I'm really looking forward to seeing uh...time.
對的，它就是一刻瞬間...引爆的瞬間，而我真的很希望看到啊...時間。
Yeah, exactly! It's not just one moment. This is a M320 Miro Phantom camera, and what do you hope to learn here?
是啊，沒錯!它不只是一瞬間。這是一台M320 Miro Phantom攝影機，你希望在這裡研究些什麼？
I just wanna be impressed, so uh...do it. Three...two...one...zero!
我只是想要看到一些不一樣的東西，所以啊...來吧。三...二...一...零!
Alright!
好的!
Pretty cool. Let's look at the video.
好酷。讓我們看看影片。
Oh, we get ripple. Yeah.
噢，有波浪。對啊。
OK, so we decided we wanted a lower exposure time and also a higher frame rate. So what we're gonna do is we're gonna change the lens.
OK，所以我們決定要用較短的曝光時間以及同時較高的畫面更新率。我們要做的就是要換個鏡頭。
Three...two...one...zero!
三...二...一...零!
About twenty feet... Yup...
大約二十英呎... 對...
Man! The uh... I wonder if that was from impact or if...if the bottle itself... No, it sucks in... There's cavitation appears on the top if you looked at the photograph.
天啊!那啊... 我懷疑它是否從衝擊產生或者是瓶子它本身...不，它收縮了...如果你看看照片，頂端出現空穴作用。
Yeah? Yeah. Alright, let's just look at the video.
是嗎？對。好吧，我們來看看影片。
Alright, I have a scientific mystery that I need your help figuring out. Let's first define what an explosion is, alright? So basically it's a rapid formation of gas, and you have it contained in some type of mechanical device, and it increases pressure. And that mechanical restraining device will eventually fail and blow outwards, correct? But here's the question. After each shot I would go find the bottle on the ground, and the bottle would be sucked in on the top instead of blown out like you would think. This is counter intuitive, and we have to figure out why.
好吧，我有個科學上的謎需要你幫忙理解。我們先來定義什麼是爆炸，好嗎？所以基本上它是氣體的快速生成，然後你把它裝在某種機械裝置(在這指寶特瓶)裡面，它增強壓力。而那機械限制裝置最終會失效並向外爆開，對嗎？但這就是問題所在。每次爆炸之後我找到地上的瓶子，而瓶身會在頂端的地方收縮，而不是像你所想像一般爆開。這和直覺是相反的，而我們必須了解為什麼。
My theory is that as the bottle blows up on the bottom, it begins to shoot up like a rocket, and when it does this, it starts to wrinkle like grandma legs if you can see it, as it pushes the rest of the bottle forward.
我的理論是當瓶子從底部爆炸時，它就開始像是火箭一樣往上噴射，而當它這麼做時，若你能看見，它像是奶奶的腿一樣開始產生褶皺，就在它推動其餘瓶身向前進的時候。
Now, the cap has more mass than the side walls of the bottle, so my theory was that the bottle was pushing the cap, but the cap weighs too much, and so the bottle is outrunning the cap.
既然，蓋子的質量比瓶子側壁要大，所以我的理論是瓶身在推動瓶蓋，但瓶蓋太重，所以瓶身超過了瓶蓋(往外爆開的量)。
Alan on the other hand disagreed with me. My position is that after detonation there's nothing but high pressure in the bottle, but Alan referenced me back to some of his photos from his Flickr stream. He always sees bubbles after detonation. Always. What causes bubbles to form in a liquid? Of course. Cavitation.
相對的，Alan和我意見不一。我的立場是在引爆之後，瓶子裡沒有任何東西只有高壓，但Alan要我回去參考一些他在Flickr照片組上的照片。他在引爆後老是看到氣泡。老是看到。是什麼東西使氣泡在液體中生成？當然。空穴作用。
A phase diagram is a fancy chart that uses pressure and temperature to describe what state the matter should be in. We're located about right here, which is twenty-three degrees Celsius. Now, there's only a couple of ways we can go from liquid over to vapor. One is we can move along to right here and increase the temperature. I don't think we're heating the water up enough in order to do that.
相圖是一個華麗的圖表，它使用壓力和溫度去描述這物質應該處在什麼樣的狀態。我們大約就在這裡，攝氏二十三度。現在，我們只有幾種方法能夠從液態轉變成氣態。其中之一是我們可以往這邊移動到這裡，並提升溫度。我不認為我們將水加熱到足以那樣做。
So I would conclude that Alan is correct. I believe we are lowering the pressure enough that we go beyond this vapor boundary and turn into vapor. And all we have to do to turn it back into a liquid is repressurize.
所以我會推論Alan是對的。我相信我們是在降低壓力至足以超過這氣化的界線然後轉變成氣態。然後我們把它變回液態所要做的只是再次施加壓力。
OK, let's look at the cavitation. Immediately after detonation, we're seeing bubbles all over the bottle. That's interesting, but a hundred and fifty microseconds later on the next frame, all the bubbles seem to be confined in one area. Basically the shock waves are bouncing off the sides of the cylindrical bottle on the inside, and they're bouncing back toward each other, and then they're interfering with each other and creating a low pressure spot. I think that's pretty cool because you can already see the cap beginning to suck in.
OK，我們看看 空穴作用吧。引爆之後瞬間，我們看到整個瓶子充滿氣泡。那很有趣，但在一百五十毫秒之後的下一個畫面，所有的氣泡似乎侷限在一個區域中。基本上衝擊波從圓柱狀的瓶身內部邊上反彈，然後它們互相反彈，然後它們互相干擾製造出一個低壓區。我認為那很酷，因為你已經可以看到瓶蓋開始收縮。
On the next frame you can see what I call the "Wrinkly Grandma Leg Effects." Now I think it's pretty interesting that the bubble is collapsing from the left to the right, which might mean that's a compression wave going towards the front of the bottle.
在下一個畫面你可以看到我說的「祖母皺摺的腿作用」。於是我認為這很有趣，氣泡由左至右瓦解，也許意味著那是個往瓶身前端的壓縮波。
But what's confusing to me is the cap of the bottle is still being sucked in. So I convinced Alan to do a self-portrait with me, but what I didn't realize is this self-portrait would reveal more information than any of the other videos.
但讓我感到困惑的是瓶蓋仍然被吸進去。所以我說服了Alan和我做個自拍照，但我所不了解的是這自拍照比起其他的影片還會揭露更多資訊。
At the point of detonation, clearly we have high pressure in the bottle. Then you can see the lid suck in. And then...check that out. The lid shoots off. So that implies to me that you have low pressure, and then high pressure. Once the fluid is blown out of the bottom of that bottle, it begins to pull fluid out of the top of the bottle with it. So we have an oscillation in pressure. Where have we seen something like that before?
在引爆的那一刻，明顯的我們在瓶子裏面有很高的壓力。然後你可以看到蓋子吸進來。 然後...看看那個。蓋子噴射出去。所以那暗示著我，你有了低壓，然後接著是高壓。一旦液體爆出瓶子底部，它開始將液體從瓶子頂端拉出。所以我們有一個壓力震盪。我們以前在哪邊看過像那樣的東西？
Sometimes when I'm drinking with a straw, I like to put my finger over the end of the straw and bring the fluid up out of the cup. And then I'll release my finger and watch what the liquid does. It oscillates. That's pretty cool, and I think that's caused by fluid momentum or the inertia of the fluid itself.
有時候當我用吸管喝東西，我喜歡把手指按到吸管頂端並把液體拉起來到杯子外面。然後我會鬆開我的指頭並觀察液體會怎樣。它會震盪。那很酷，而且我認為那是由液體動量或液體本身的慣性所造成。
So this momentum effect of fluid applies to what we're doing too. As the fluid is blown out of the bottom of that bottle, you can see that it starts to pull liquid out of the top of the bottle and collapse the side walls of the bottle. That's pretty cool too.
所以這液體的動量效果也適用於我們正在做的東西。當液體爆出那瓶子底部，你可以發現它開始把液體從瓶子頂端拉出來然後使瓶身的側壁崩潰。那也很酷。
So seriously, thanks for your time. It's way more fun to think this through with you. Anyway, if you want the high speed footage, feel free to download it. Draw me some pictures and show me what you think the shock waves are doing on the video. This guy did it. I don't think he's exactly right, but he took a good stab at it. I'm Destin. You're getting Smarter Every Day. Have a good one.
所以說真的，感謝你的時間。和你一起把這件事徹底想清楚很有趣。不論如何，如果你想要這高速攝影影片，請自行下載。畫幾張圖給我看，告訴我你認為震波在這影片中是怎麼運作的。這個人已經這樣做了。我不認為他完全正確，但他做了很棒的嘗試。我是Destin。你在收看Smarter Every Day。祝你好運。
Two...one...zero...
二...一...零...
By the way, Alan Sailer grows very good apricots.
對了，Alan Sailer種了很棒的杏樹。
The Russians have developed a way to use cavitation to create a bubble on the front of the torpedo. This is called Super Cavitation. If you fly the torpedo in that bubble, you have way less drag, and you can move that torpedo way fast.
俄國人已經研發出了一個方法用空穴作用在魚雷前端創造出一個氣泡。這叫做「超空蝕」。如果你讓魚雷在那氣泡中飛行，你的阻力會小得多，而且你可以讓魚雷移動得快許多。
