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如何让液体爬起来

How to make fluid "climb" up! AMAZING SLIME EXPERIMENT!

感谢好奇流媒体对PBS数字工作室的支持
Thanks to CuriosityStream for supporting PBS Digital Studios.
嘿 我是戴安娜 你正在收看“物理女孩”
Hey, I’m Dianna. You’re watching Physics Girl.
我特别想做一期节目
And a video that I really like to make is
来介绍各种你可以在家尝试的物理实验
a bunch of different science experiments that you can try at home.
于是我们买齐了能做六种不同实验的材料
So we bought all the materials for like six different experiments,
其中包括一堆冰箱里“不是为了喝”的牛奶
which is a lot of milk in my fridge that says “Do not drink”.
但是我们甚至一个实验都没做完
But we didn’t even get pass the first experiment,
因为太酷了!
because it was so cool.
本期视频将会是其中之一 来试试吧
So this video is gonna be a listicle of one. Check it out.
当你把一根细棒 比如玻璃棒
When you put a thin rod, like a glass stirring stick,
插进均有特殊性质的液体中
into a fluid that has specific properties,
然后转动玻璃棒
and then spin the rod,
这个液体会有不寻常的反应
it does something fluids don’t usually do.
液体会顺棒而上
The fluid travels up the rod,
当然 不是所有液体都这样
not all fluids would do this, of course.
我知道你已猜到这些紫色的玩意有特殊性质
I know you know that purple stuff has special properties.
这是最风靡网络的液体
It’s the most viral fluid on the Internet.
他就是史莱姆
This is slime
我们刚才看到的现象被称为韦森堡效应
And what we’re seeing here is called the Weissenberg effect.
一般液体并没有这种效应
It’s not normal behavior for a fluid.
你要是打过巧克力蛋糕糊
If you’ve ever beaten brownie mix,
就会知道面糊是会向周围飞散的
you know that the fluid tends to fly off in all directions.
而且不会顺着搅拌器爬上来
And it certainly doesn’t climb in and up the mixer.
不过能爬到我肚子里去
It climbs into my belly though.
韦森堡效应会在非牛顿流体中发生
So the Weissenberg effect happens with non-Newtonian fluids,
下面我来解释一下
and I’ll talk about what those are.
这现象太酷了
But it’s so cool.
我们想直观的看看它们如何移动
We wanted to be able to visualize how the fluid is moving,
于是就做了一些不同颜色的史莱姆
so we made a few different colors of slime,
把它们放进同一容器里
and then put them together in a container,
再把玻璃棒插到交汇点上
so we could draw the liquid up the rod
来让这些粘液顺棒而上
from the point where all the colors meet.
这不过是我想调出漂亮颜色的借口
This was just an excuse for me to make pretty colors.
我是个颜色控
I love colors.
下面是见证奇迹的时刻
So this is what happened with the colors.
为什么会这样?
Why does this happen?
什么是韦森堡效应呢
What is the Weissenberg effect,
不就是某个人命名的什么效应嘛
besides just another effect named after some dude?
我问了我的朋友Dan 一个等离子物理学家
I talked to my friend Dan, who is a plasma physicist
这些颜色都是他帮忙搞定的
and also happens to be the friend who helped me with the colors,
到底怎么回事呢?
about what’s going on.
这就是……所谓的史莱姆
So this is a… they call it slime.
它能像液体一样流动
It flows like a fluid.
所以 如果我这样拿着
So if I hold it like this,
它能流动 就像液体一样
it’ll flow as if it’s a fluid.
但如果我突然拽一下 它会裂成两半
But if I pull it suddenly, it even snaps in half.
液体被这支笔所牵引 并围着它转动
The fluid moving around and getting dragged along this pen.
不过任何液体都这样
That’s gonna happen in any fluid.
– 水也这样?- 是的
– In even water.- Even water, yeah.
但这种液体有种独一无二的性质
But with this fluid, this material also has
叫做“粘弹性”
a unique property called viscoelasticity.
它不仅有粘性
Not only is this fluid viscous,
而且会弹回原来的位置
but it will bounce back to its original position.
并非所有液体都这样
That’s not the case with all fluids.
这种液体所具的弹性
The elasticity of this fluid
会使它恢复原来的形状 对吧?
makes it wanna come back to its original position, right?
下面 我将用这根线做个模型
So, I’m gonna use this string as a model for that.
随着纸卷的转动
So, as this turns…
这是科学的声音…
That’s the sound of science.
线或者液体将它缠绕起来
It wraps up this string or the fluid,
越缠越紧
it’s tightening as it goes.
这就产生一种力量
That creates a tension.
当周围的力量作用时
When you have a tension that’s pulling around,
实际上就是个向心的作用力
it actually creates an inward force
它把这个纸筒挤扁了
that causes it to collapse.
所以想象下会发生什么
So think about what’s gonna happen,
当圆柱状的液体向内挤的时候
when this cylinder of fluid starts to squeeze in.
内侧的液体就会被推上去
It’s gonna push the inner fluid up.
这就是韦森堡效应
And that’s what’s driving the Weissenberg effect
它使得液体在这根棒上越爬越高
to send this up higher and higher of the rod.
所以说 韦森堡效应
So the upward motion of the Weissenberg effect is
实质上是液体把自己往上挤的爬杆行为
essentially the fluid squeezing itself up the rod.
好温馨的自我拥抱
A nice self hug.
这有点像
It’s also kinda like spaghetti,
你用叉子卷意大利面的情况
when you twirl it around a fork,
只不过面条不是液体罢了
except spaghetti is not a liquid,
不过进了我的肚子就难说了
until it’s in my belly.
嗯 说着就饿了
Um, I’m hungry.
我提到过这个效应发生在非牛顿流体中
I mentioned that this works with non-Newtonian fluids.
但是我没有解释这个词
I didn’t tell you what those are.
所以牛顿流体是一种平常的液体
So a Newtonian fluid is a fluid that acts normally.
像是水
It’s like water.
如果你用吸管来吸它
If you suck water up a straw,
你吸的越用力
The harder you suck,
上来的水越多
the more water will come up.
但对非牛顿流体来说
But with non-Newtonian fluids,
如果你削它们一下 或者说叫剪切力
if you put something called shear, shear strain on them,
就像这样滑动的动作
which is kind of this sliding kinda motion.
一些像史莱姆的非牛顿流体会变粘稠
There’s some non-Newtonian fluids like this kind like slime, They get thicker.
这叫做剪切增稠液体
They’re called shear thickening fluids.
这样 史莱姆的弹性和剪切变稠性质
And it’s the elasticity plus the shear thickening of the slime
使得你在旋转拉伸它的时候
that causes it to tighten around itself,
它反而会紧紧的把自己包起来
as you’re stretching it out with the twists.
流体力学…
Fluid dynamics.
你一定要在家试试这个实验
This experiment, this demo you must try at home.
如果你想做出有韦森堡效应的粘液
And if you wanna make your own slime and do the Weissenberg,
可以看看我的配方
here’s the recipe that we used.
半杯水 半杯PVA胶水混合在一起
1/2 cup of water mixed with 1/2 cup of PVA glue,
或这种多用途的可水洗白胶水
or that washable multi-purpose white glue.
这是Elmer牌的
It’s Elmer’s people.
另外准备半杯温水
And then separately mix 1/2 cup of warm water
放入1/4茶匙硼砂
and 1/4 teaspoon of borax.
然后全部混合就好了
Then mix all that together, then perfect.
你还可以加点食用色素 荧光粉
You can also add food coloring to the water or add glitter,
香蕉泥什么的 随便你
or mashed bananas or whatever you want.
出现韦森堡效应的关键是
And the key to see the Weissenberg fact is
让细棒可以慢慢的旋转
to get a rod that you can make spin slowly.
对某些非牛顿流体来说
You can even do it by hand,
用手旋转就可以(观察到韦森堡现象)
with some types of non-Newtonian fluids.
如果你不满足于仅仅观察一下 而是想做个实验
And if you wanna turn this into an experiment rather than just a demo,
你可以试着改变一下
try controlling the amount of borax
加入的硼砂和胶水的量
versus the amount of glue that you put in,
来看看你能让史莱姆爬多高
and see if that affects how far you can get it to climb up the rod,
或者其他什么的
or try something else.
但不论你做什么
But whatever you do,
只要你做了 记得推特我
if you try this at home, you’d better twitter it at me.
用#科学的史莱姆…为科学献身的史莱姆
Use the #scienceslime… slimeforscience.
谢谢观看
Thanks for watching this video.
和水有关的好玩实验很多
I’ve got another video that’s a bunch of
我这还有一期相关视频
fun demos you can do with water.
记得看哦
So check that one out.
如果你想看更多好玩的物理现象 请订阅我们
Subscribe, if you want more physics and happy physics thing.
最后我得再谢谢好奇流媒体对PBS数字工作室的支持
Hey, I’d like to thank CuriosityStream for supporting PBS Digital Studios.
好奇流媒体提供纪录片和纪实题材的订阅服务
CuriosityStream is a subscription streaming service that offers documentaries
它们有自己的制作队伍 有很多原创节目
and nonfiction titles from a variety of filmmakers, including CuriosityStream originals.
比如说 你可以查查空间探测器
For example, you could check out Space Probes.
那有6期系列视频
There are six-part series all about space probes
是关于发射到太阳系去寻找其他世界的探测器的
that we’ve sent out into our solar system to investigate other worlds.
如果你想学到更多 输入“curiositystream.com/physicsgirl”
If you’d like to learn more, go to curiositystream.com/physicsgirl
登陆的时候用”physicsgirl”做验证码就行啦
and use the code “physicsgirl” during the signup process.

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译制信息
视频概述

非牛顿流体中爬杆效应的直观讲述

听录译者

jm

翻译译者

拟态

审核员

审核员 RN

视频来源

https://www.youtube.com/watch?v=Z99bsizp4bY

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