Name: 科學無法弄清為什麼有些液體會流動 (Science Can’t Figure Out Why Some Liquids Flow)
Uploaded: 2022-06-09T18:00:23.000Z
Duration: 5 min 47 s

Fluids are a necessary part of everyday life.

液體是日常生活中的一個必要部分。

After all, without water you couldn’t live, and without chocolate syrup, well, what would

畢竟，沒有水你就無法生存，而沒有巧克力糖漿，那麼，什麼會

But have you ever noticed that not all liquids behave the same?

但你有沒有注意到，並不是所有的液體都表現得一樣？

In fact, some of them do some pretty bewildering stuff under the right circumstances, and even

事實上，他們中的一些人在適當的情況下會做一些相當令人困惑的事情，甚至是

after decades of research scientists are no closer to understanding why.

經過幾十年的研究，科學家們並沒有更接近於瞭解原因。

One question about strange fluids may have finally been answered thanks to some glass

關於奇怪液體的一個問題可能終於得到了答案，這要感謝一些玻璃

beads and—I always love saying this—laser beams.

珠子和我總是喜歡說這個--激光束。

All liquids that we encounter in the real world can be boiled down to one of two kinds.

我們在現實世界中遇到的所有液體都可以歸結為兩種之一。

They’re either Newtonian, or non-Newtonian.

它們要麼是牛頓的，要麼是非牛頓的。

Newtonian fluids are pretty easy to grasp.

I mean, not literally in some cases—a Newtonian fluid like water would squirt right out of

我的意思是，在某些情況下不是字面上的，像水這樣的牛頓流體會直接噴出。

But chocolate syrup is also Newtonian even though it would slowly dribble out of your

但巧克力糖漿也是牛頓式的，儘管它會慢慢地從你的身體裡滴出來。

hand, maybe as you frantically lick your palm to get as much of that rich goodness before

掌心，也許當你瘋狂地舔著你的手掌，以獲得儘可能多的那份豐富的美味之前

In other words, chocolate syrup is much more viscous than water.

換句話說，巧克力糖漿的粘性比水大得多。

Viscosity is a measure of a fluid’s resistance to flow.

粘度是衡量流體對流動的阻力。

It’s basically the friction between molecules in a fluid.

它基本上是流體中分子之間的摩擦。

The higher the viscosity, the slower the flow.

A Newtonian fluid obeys Newton's Law of Viscosity which means its viscosity is constant.

牛頓流體遵守牛頓粘度定律，這意味著其粘度是恆定的。

It doesn’t change when a force is applied to it.

當一個力施加在它身上時，它不會改變。

Non-Newtonian fluids, on the other, less sticky hand, do change their viscosity…which can

非牛頓流體，在另一方面，不那麼粘稠，確實改變了它們的粘度......這可以

導致了一些相當瘋狂的惡作劇。

There are different sub-categories of non-Newtonian fluids depending on how their viscosity changes.

非牛頓流體有不同的子類別，這取決於其粘度的變化方式。

There are dilatants whose viscosity increases as force is applied.

有一些稀釋劑的粘度會隨著力的作用而增加。

Examples of dilatants include quicksand, silly putty, and the cornstarch-water mixture known

稀釋劑的例子包括流沙、傻子膩子和已知的玉米澱粉-水混合物。

在一年級的教室裡，有一種叫做 "奧布拉克 "的東西。

The tiny corn starch particles in oobleck can flow freely with the water molecules if

泡泡糖中的微小玉米澱粉顆粒可以與水分子自由流動，如果

you gently dip your fingers in, but give it a good smack and the cornstarch locks up,

你可以用手指輕輕地蘸一下，但只要輕輕一拍，玉米澱粉就會被鎖住。

giving oobleck a surprisingly solid character.

賦予橡皮泥一個令人驚訝的堅實性格。

You could straight up run across a swimming pool if you dumped enough cornstarch in it.

如果你在游泳池中傾倒足夠的玉米澱粉，你可以直接跑過游泳池。

But, there are vandalism laws so, y’know… don’t.

但是，有破壞性的法律，所以，你知道......不要。

Some fluids get more viscous when force is applied, but the opposite can also be true.

有些液體在受力時變得更加粘稠，但也可能是相反的情況。

Ketchup is in a category of non-Newtonian fluids called pseudoplastics.

番茄醬屬於非牛頓流體的一個類別，被稱為假塑性流體。

When no force is applied, it just sits there.

當沒有施力時，它只是坐在那裡。

But when you give the back of the bottle a whack the viscosity decreases and the ketchup

但當你在瓶背上拍打一下時，粘度就會下降，番茄醬就會

Inside the sauce at a molecular level what’s happening is long chains of atoms called polymers

在醬汁內部，在分子水準上，正在發生的是稱為聚合物的原子長鏈。

get tangled together and hold fast, but when smacked or shaken, they stretch out and align,

糾纏在一起，緊緊抓住不放，但當抽打或搖晃時，它們就會伸展開來，保持一致。

allowing the gooey red paste to slide around, hopefully onto your french fries but probably

讓粘稠的紅色糊狀物滑來滑去，希望能滑到你的炸薯條上，但可能是

Still there are many more weird non-Newtonian behaviors scientists don’t have answers

仍然有許多奇怪的非牛頓行為科學家沒有答案

They may have just solved one riddle that’s stood for over 50 years.

他們可能剛剛解決了一個存在了50多年的謎題。

The problem was first noticed in the 1960s when engineers were attempting to extract

這個問題第一次被注意到是在20世紀60年代，當時工程師們正試圖提取

oil from the ground with fluids that contained long-chain polymers.

用含有長鏈聚合物的液體從地下開採石油。

Pumping these so-called “pusher fluids” into the ground below a certain rate worked

將這些所謂的 "推注液 "泵入地下，低於一定的速度，就會產生效果

fine, but pumping them faster would cause them to become much more viscous, like oobleck.

很好，但是抽得更快會使它們變得更加粘稠，就像橡皮泥一樣。

The fluids would only behave this way when flowing through the microscopic spaces between

液體只有在流經兩邊的微觀空間時才會有這樣的表現。

soil; when not confined to the twisty windy paths in a porous medium, the fluids’ viscosity

土壤；當不侷限於多孔介質中的曲折風路時，流體的粘度

would actually drop as more force is applied, like ketchup.

實際上會隨著施加更多的力而下降，就像番茄醬。

For a while, scientists thought maybe the polymers were clogging up the pores in the

有一段時間，科學家們認為可能是聚合物堵塞了孔隙。

soil, but that couldn’t explain how the fluids flowed easily when the flow rate dropped

土壤，但這並不能解釋當流速下降時，液體是如何輕鬆流動的。

It wasn’t until a new study was published in late 2021 that scientists think they might

直到2021年底發表的一項新研究，科學家認為他們可能

Part of the problem they’ve had is soil and other porous media aren’t see-through,

他們遇到的部分問題是土壤和其他多孔介質是不透明的。

so it’s hard to tell what’s going on down there.

To solve this they created a custom medium out of glass beads.

為了解決這個問題，他們用玻璃珠創造了一種定製介質。

And they concocted a polymer solution with the same refractive index of the glass, meaning

他們調製了一種聚合物溶液，其折射率與玻璃相同，這意味著

the liquid and solid would both bend light exactly the same way.

液體和固體都會以完全相同的方式彎曲光線。

To see the windy paths fluids would follow in the spaces between the beads, the researchers

為了看到液體在珠子之間的空間裡的風行路徑，研究人員

added a red dye to the solution that would give off a certain wavelength of light when

在溶液中加入一種紅色染料，當它發出某種波長的光時，就會發出某種波長的光。

To visualize how the fluid was moving, they added tracer particles that would emit

為了直觀地看到流體是如何移動的，他們添加了會發出 "嗡嗡 "聲的示蹤粒子。

a different color when excited by another laser.

當被另一個激光器激發時，會出現不同的顏色。

With this extremely complicated setup in place they observed the fluid flowing at different

有了這個極其複雜的裝置，他們觀察到流體以不同的速度流動。

rates and found that the long polymers in it started tumbling around as the fluid moved

速率，並發現其中的長聚合物在流體移動時開始翻滾。

This movement pushed on other nearby molecules in the liquid and created a phenomenon called

這種運動推動了液體中其他附近的分子，併產生了一種稱為

“elastic turbulence,” creating eddies and slowing the whole fluid down.

"彈性湍流"，產生渦流，使整個流體速度減慢。

The researchers think this new understanding of why pusher fluids suddenly become so viscous

研究人員認為，這種對推注液為何突然變得如此粘稠的新認識

could be useful for purifying groundwater.

It may aid in the development of new polymer-containing solutions that can force water through rocks,

它可能有助於開發能夠迫使水穿過岩石的新的含聚合物溶液。

But there’s more work to be done because elastic turbulence itself isn’t fully understood.

但是還有更多的工作要做，因為彈性湍流本身並沒有被完全理解。

Maybe that’ll be the next riddle solved.

也許這將是下一個解開的謎題。

Or maybe first we’ll get an answer for why people like ketchup on scrambled eggs.

或者首先我們會得到一個答案，為什麼人們喜歡在炒蛋上加番茄醬。

Granted that has nothing to do with its non-Newtonian properties but it’s still

儘管這與它的非牛頓特性無關，但它仍然是

something I just can’t wrap my head around.

Thanks so much for watching, don't forget to subscribe, and I'll see you for the next Seeker.

非常感謝你的觀看，別忘了訂閱，我們下期《探索者》再見。