令人惊叹的蜂蜜盘绕高速视频！- 每天聪明一点点 53：英语精读讲义

Hey, it's me, Destin.

嘿，是我，Destin。

Welcome to Smarter Every Day.

欢迎收看Smarter Every Day。

And today we're going to show you some pretty cool high speed

今天我们要向你们展示一些非常酷的高速画面，

and it has nothing to do with all those assault rifles. 短語搭配

这和那些突击步枪没有任何关系。

It's actually much sweeter than that, 習語

其实它比那要甜得多，

literally.

字面意义上的甜。

Check this out. 短語動詞

看看这个。

It is a jar of honey.

这一罐是蜂蜜。

So,

那么，

I know this sounds a little strange, 表達脈絡

我知道这听起来有点奇怪，

but we've got a high speed camera set up 短語動詞

但我们架设了一台高速摄像机，

and we are going to show you something called the liquid rope coil effect. 用詞

我们要向你展示一种叫做“液体绳卷绕效应”的现象。

This is how it works.

它是这样运作的。

You just put some of the honey on this chopstick here

你只要把一些蜂蜜挑在这根筷子上，

and just drip it down

然后让它滴下来，

and look at this.

看看这个。

Check out that.

仔细看看。

How cool is that? 語氣意圖

这有多酷？

It has to do with the viscosity of the fluid

这与流体的黏度有关，

and basically the liquid is piling up. 短語動詞

简单来说就是液体在不断堆积。

So, I think this is really really neat.

所以，我觉得这真的非常非常巧妙。

So, we're going to get a little bit of high speed of it

接下来我们要用高速摄像机拍一下，

and then after that

然后在那之后，

we're going to discuss this

我们将讨论这个现象，

in uh more detail.

了解它的更多细节。

Fluid dynamics are awesome.

流体力学太棒了。

It's tempting to think that this would be an easy math problem, 表達脈絡

人们很容易认为这是一个简单的数学问题，

but it turns out people have been studying this for 50 years. 語法

但事实上，人们已经对此研究了50年。

To explain, 表達脈絡

为了解释清楚，

let me show you the variables.

让我给你看看这些变量。

This section is called the coil

这一部分叫做卷绕区，

and this section is called the tail.

这一部分叫做尾部区。

The coil and the tail together make up the total height h. 短語動詞

卷绕区和尾部区加起来就是总高度 h。

The mass flow rate of the material is q 用詞

物质的质量流量是 q，

and the initial radius at the top of the tail is called a sub zero.

尾部顶端的初始半径被称为 a0。

We'll call the radius at the bottom a sub one

我们把底部的半径称为 a1，

and the exciting part is the angular coiling frequency,

最令人兴奋的部分是角卷绕频率，

which is omega.

也就是 omega。

The fluid itself also has internal properties that we have to consider.

流体本身也有我们必须考虑的内部特性。

Density is rho

密度是 rho，

and the surface tension coefficient is gamma.

表面张力系数是 gamma。

The kinematic viscosity is nu.

运动黏度是 nu。

Okay,

好了，

simply put viscosity is the measure of the thickness of a fluid. 表達脈絡

简而言之，黏度是衡量流体浓稠度的指标。

Viscosity is the measure of a fluid to resist a shear or tensile stress.

黏度是流体抵抗剪切或拉伸应力的量度。

Dynamic viscosity is measured in poise,

动力黏度的单位是泊（poise），

whereas kinematic viscosity is measured in stokes. 語法

而运动黏度的单位是斯托克斯（stokes）。

Kinematic viscosity is also referred to as the diffusivity of momentum 短語搭配

运动黏度也被称为动量扩散率，

and that makes sense if you think about it,

仔细想一下，这是有道理的，

to diffuse momentum throughout a fluid.

也就是将动量扩散到整个流体中。

As you can see here,

正如你在这里看到的，

obviously the molasses honey mixture is the most viscous.

显然糖蜜和蜂蜜的混合物是最黏稠的。

Okay,

好了，

if these big words are boring you,

如果这些生僻字眼让你觉得无聊，

just wait.

稍等一下。

There's a shower scene for you.

马上就有一场沐浴戏要上演了。

But if you're like me and you want to understand what's going on 短語動詞

但如果你和我一样，想要理解发生了什么，

and you want to know the math,

并且想了解其中的数学原理，

let's do this.

那我们开始吧。

What you're looking at here are the four different types of flow

你现在看到的是四种不同类型的流动状态，

that scientists can describe using the variables that we defined earlier.

科学家可以用我们刚才定义的变量来描述它们。

Let's start here with this one.

我们从这个开始。

This is the viscous flow regime.

这是黏性流动状态。

The way it works is as h or the height that the fluid is dropped from is relatively small,

它的原理是，当 h（流体滴落的高度）相对较小时，

the flow has to naturally go into a spiral

液流必然会自然形成螺旋状，

because the fluid has to get out of the way of itself. 習語

因为流体必须给自己让路。

Now,

那么，

the interesting thing about the equation used to define the coiling frequency 語法

用来定义卷绕频率的方程中，有趣的地方在于，

is that it doesn't even include the kinematic viscosity of the fluid.

它甚至没有包含流体的运动黏度。

That's interesting seeing how it's called the viscous flow regime. 語法

这很有趣，毕竟它被称为黏性流动状态。

Okay,

好了，

the second condition we're talking about here is called the gravitational flow regime.

我们要讨论的第二种情况叫做重力流动状态。

Basically,

基本上，

the way it works is as that height increases,

它的原理是，随着高度增加，

gravity begins to take over and stretch the fluid. 短語動詞

重力开始占据主导并拉伸流体。

So,

所以，

basically the viscosity of the fluid is resisting that stretching

基本上，流体的黏度在抵抗这种拉伸，

and that's why the equation there shows that kinematic viscosity starts to come into play. 習語

这就是为什么那里的方程显示，运动黏度开始起作用。

That's where the coiling becomes uniform and stable.

在这个状态下，卷绕变得均匀且稳定。

That's the exact condition that we were filming with the high speed camera earlier.

这正是我们早些时候用高速摄像机拍摄时的条件。

The third condition we're going to talk about is called the inertial regime.

我们要讨论的第三种情况叫做惯性状态。

Now,

那么，

as height gets very very long,

当高度变得非常非常高时，

what happens is that fluid becomes very fast and very very skinny.

发生的情况是，流体变得非常快且非常非常细。

Now,

现在，

you notice in the equation that the radius of the coil at the bottom

你会注意到在方程中，底部卷绕的半径

is factored into the denominator and raised to the 10th power. 用詞

被放入分母中，并提高到 10 次方。

Now,

那么，

if you think about it,

如果你仔细想想，

that means the smaller the radius gets, 語法

这意味着半径越小，

the higher the coiling frequency,

卷绕频率越高，

which makes sense.

这很有道理。

Okay,

好了，

the fourth regime is why I love science.

第四种状态是我热爱科学的原因。

All we know is that somewhere between the gravitational regime and the inertial regime, 語法

我们只知道，在重力状态和惯性状态之间的某个地方，

everything goes out the window. 習語

一切常规都不适用了。

All of a sudden you'll go from a steady state coil 短語搭配

突然之间，你会从稳定的卷绕状态

to some erratic figure eight pattern or something stranger.

变成不规则的 8 字形，或者更奇怪的形状。

But if you raise it just a little bit more,

但如果你再稍微提高一点高度，

all of a sudden you're steady state again.

突然之间，它又恢复稳定状态了。

Even more and you're back unstable.

再高一点，它又变得不稳定了。

Everything is erratic.

一切都变得不规则。

The frequency is varying wildly,

频率变化剧烈，

but it seems to have some sort of pattern, 短語搭配

但似乎又存在某种规律，

but we don't know why.

只是我们不知道为什么。

It's very interesting and there's been a very complex study done on it

这非常有趣，已经有一项非常复杂的研究针对它进行了探讨，

and I'll leave a link in the description to that

我会在简介里留下链接，

so you can check it out yourself.

以便你可以自己去看看。

I think it's amazing that we as humans can conquer so many things about the world around us,

我觉得很神奇，作为人类我们可以征服周围世界的这么多事物，

but we still struggle with the smallest of things.

但我们仍然在最微小的事情上挣扎。

If you're interested in knowing why I did this video, 語法

如果你有兴趣知道我为什么做这个视频，

I'll leave that info in the description as well.

我也会把那部分信息留在简介里。

Boy,

天哪，

that got weird in a hurry, 習語

画风怎么一下子变奇怪了，

didn't it? 語法

是吧？

Every single day you can check out the liquid rope coil effect in your own shower.

每一天你都可以在自己的淋浴间里观察到液体绳卷绕效应。

It's pretty easy.

这很简单。

Just take your shampoo,

只需拿你的洗发水，

which is a pretty viscous fluid,

那是一种相当黏稠的流体，

and throttle the flow rate and the height 用詞

控制流量和高度，

until you get the right combination

直到你找到正确的组合，

and then boom,

然后砰的一声，

you lock in on the liquid rope coil effect. 短語動詞

你就锁定了液体绳卷绕效应。

It's pretty cool.

这非常酷。

You can change things and see how the variables affect its action.

你可以改变条件，看看这些变量如何影响它的行为。

Anyway,

不管怎样，

I'm not responsible for any extra shampoo you end up using. 短語動詞

我可不对你多用的洗发水负责。

I'm Destin.

我是 Destin。

You're getting smarter every day.

你每天都在变得更聪明。

Have a good one. 語氣意圖

祝你愉快。