So to fly slow is one of the more difficult things to do because you don't have as much airflow over

所以，要想慢速飛行是比較困難的事情之一，因為你沒有那麼多的氣流在上面。

your control surfaces. To fly at zero air velocity is the hardest thing to do of all.

你的控制面。以零空速飛行是最難做到的事情。

Over the past weekend I've been making observations of hummingbird flight

在過去的週末，我'一直在做蜂鳥飛行的觀察。

in my back yard. So let's look at my observations and then we'll come back, and we'll look

在我的後院。所以，讓我們看看我的觀察，然後我們'會回來，我們'會看看。

at the science of how hummingbirds fly. You're getting Smarter Every Day.

在蜂鳥如何飛行的科學。你每天都在變得更聰明。

[music]

[音樂]

So what does olive oil and lasers have in

那麼橄欖油和脈衝光有什麼關係呢？

common. Hummingbirds obviously. Dr Doug Warrick

常見的。蜂鳥顯然。道格-沃裡克博士

at Oregon State University and Dr Brett Tobalske at University of Montana have been

俄勒岡州立大學的Brett Tobalske博士和蒙大拿大學的Brett Tobalske博士已被任命為該校校長。

studying hummingbirds by using a nozzle to spray olive oil

用噴頭噴灑橄欖油研究蜂鳥。

in the air around a hummingbird. And then they'll take a laser and then they'll

在蜂鳥周圍的空氣中。然後，他們會採取脈衝光，然後他們'll

slice sections of the air where the olive oil is, to measure

切片的空氣中的橄欖油的部分，以測量。

the flow field. Basically it's called digital particle image

的流場。基本上，它被稱為數字粒子影像。

velocimetry. What you do is you get a picture of an oil droplet, you wait

測速。你要做的是得到油滴的照片，然後等待。

some finite amount of time later and then you get another picture of an oil droplet. That gives you

在有限的時間後，你會得到另一張油滴的照片。這就給了你

a two dimensional visualisation of the flow field around a hummingbird, which is awesome.

蜂鳥周圍流場的二維可視化，這很厲害。

So what you can do is you can use this information to calculate exactly

所以，你可以做的是，你可以利用這些資訊準確地計算出

what the hummingbird is doing to stay aloft. In these pictures you can see here,

蜂鳥在做什麼，以保持高空。在這些圖片中，你可以看到這裡。

you can see vortices underneath the wing. Using this technique they

你可以看到機翼下的渦流。使用這種技術，他們

discovered that about 70% of the hummingbird's lift comes from the fore stroke,

發現，蜂鳥約70%的升力來自前衝。

and 30% comes from the back stroke. It's not 50-50 like I used to think it was.

而30%來自於後衝。它'不是像我以前認為的那樣五五開。

Another thing I observed is when a hummingbird would come into the feeder, right before he'd get there

我觀察到的另一件事是，當一隻蜂鳥進入餵養器時，就在他'd到達那裡之前。

he would make this tail flick. I didn't know what that was so I called Dr Warrick and asked him.

他將使這個尾巴輕彈。我不知道那是什麼，所以我打電話給沃裡克醫生，問他。

Right now Dr Warrick and his team of biomechanists don't really know what this tail flick means.

現在Warrick博士和他的生物力學家團隊並不真正知道這種尾巴的輕彈意味著什麼。

They're not sure if he's changing the airflow around his body

他們不確定他是否改變了身體周圍的氣流。

or if he's changing his centre of gravity under his wings so that the can make a maneuver that way.

或如果他'的改變他的重心在他的翅膀下，所以可以使一個機動的方式。

What they are doing however is making a six degree of freedom model so that they can

然而，他們正在做的是做一個六自由度模型，這樣他們就可以。

study this further. If you want to learn more about it check out the links in the video

進一步研究這個問題。如果你想了解更多關於它的資訊，請查看視頻中的鏈接。

description. So a lot of you have been asking about what kind of camera I've been using. It's a Phantom made by

描述。所以很多人都在問我一直在使用的相機是什麼樣的。這是一個Phantom由

Vision Research. If you want more info on it go to the description, I'll put a link there for you

視覺研究。如果你想了解更多資訊，請到描述中去，我會給你放一個鏈接。

so you can go to the website. Other than that click the bird feeder here, and uh..

所以你可以去網站。除此之外，點擊這裡的喂鳥器，呃... ...

You can subscribe.

你可以訂閱。

Oh.. Just subscribe by clicking

哦......只要點擊訂閱

the link below, and I hope you're getting Smarter Every Day.

下面的鏈接，我希望你'每天都能變得更聰明。

[cough] That is...

[咳嗽] 這是...

That's some good stuff.

那是一些好東西。

[music]

[音樂]

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Captioning in different languages welcome. Please contact Destin if you can help.

歡迎使用不同語言的字幕。如果你能幫忙，請聯繫Destin。