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麻省理工公开课:魔术背后的化学(MP3+视频+中英字幕) 第2期:烧钱(2)

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Well, I have a jar right here and I have

这里有一个容器
in this jar, what does it look like?
容器中看起来是什么
I have a liquid, what does it look like? It looks like...
这是一种液体 像什么 它像…
looks like wate
像水
The way we describe this liquid is to say it's a clear and colorless liquid
这种液体我们将其描述为无色透明液体
which is what water i
水就是这样的
So I'm going to take this liquid and...
我将用到这种液体
so I want everybody to see the jar right here
我希望所有人都能看到这个容器
Get this out of wa
这个拿开
I'm going to take the dollar bill
我将把这张美钞
I'm going to soak it in this clear and colorless liquid which looks like water
浸入到这种像水的无色透明液体之中
And I'm going to fish it out using those tongs
我将用坩埚钳将其捞出
You see it's dripping like any wet object would, right?
和浸入水中的物体一样 有液体滴下来
And then I'm going to take it to the flam
下面把它放到火焰上
Take a good look at it. Now the joy is maybe the last time you see it
看好了 可能和之前一样哦
So here is the dollar bill on fire
美钞烧了起来
Or is it?
真的吗
But you did see a flame, didn't you?
但你们看到火焰了 不是吗
So now I ask you
现在我问你们
can this liquid be water?
这种液体可能是水吗
You know from experience that water does not burn under these condition
根据经验 你们知道浸水的纸是烧不起来的
So I will tell you what's in this jar
我来告诉你们容器里装的是什么
This clear and colorless liquid is a mixture of rubbing alcohol and wate
这种无色透明液体是擦拭酒精和水的混合物
isopropyl alcohol and wate
异丙醇和水
You know also from experience
你们从经验就能知道
that when you burn alcohol, what color of flame do you see?
醇燃烧时 应该看到什么颜色
It's kind of bluish, right?
带蓝色 对吧
Do you remember what color of flame is out here?
记得这里火焰是什么颜色吗
It was a little yellowish, right?
有些带黄色 对吧
That's because we also added a little bit of sodium chloride in there
这是因为我们还在这里加了一些氯化钠
The eye is more sensitive to the yellow color than it is to the blue color
眼睛对黄色更敏感 对蓝色则较迟钝
So we added the sodium chloride to enhance the visibility of what's going o
所以我们加了些氯化钠 来增强反应的视觉效果
Alright, so what happened there?
好 这里发生了什么呢
Dr. Shakhashiri soaked the money i
Shakhashiri博士将钱浸入到
a solution of water rubbing alcohol and a little bit of table sal
擦拭酒精和少许食盐的水溶液中
When he puts the money in the flame, the alcohol burn
之后将钱放到火焰中 酒精开始燃烧
producing heat and light, energy
生成热和光 能量
and carbon dioxide and wate
二氧化碳和水
The reaction is this
反应是这样的
There's our alcoho
这是酒精
reacting with oxygen
同氧气反应
producing carbon dioxide, water and energy
生成二氧化碳 水和能量
So why doesn't the bill burn?
那为什么钞票没有烧起来呢
If you have a beaker of alcohol and light it on fir
将一烧杯酒精在上方点燃
it's just that very top layer of alcohol and the gas above it that burn
只有最上方那层酒精和上面的气体会燃起来
the rest of the alcohol in the beaker does not
烧杯中的其它酒精则不会
So that's what's happening with our dollar bil
这里美钞的情况也是如此
Let's draw a dollar bill right her
这里我画一张美钞
So the alcohol --
酒精
ROH could be any alcohol --
ROH可以表示任何的醇
is evaporating off the bill
会从钞票上蒸发
turning into the gas
变为气体
and burnin
并燃烧
So those are the flames that you see
这些就是你所看到的火焰
but remember that the solution is 50 percent water
但要知道 溶液中有50%是水
The water is evaporating much less quickly than the alcohol
水的蒸发要比酒精慢很多
staying in the bil
留在钞票上
and preventing the paper from burning
阻碍纸张燃烧
So that's one way to hold on to your cas
这就是不让钱烧起来的方法
Hope you enjoyed money to burn, and I'll see you next time
但愿大家喜欢"烧钱"这个演示 我们下次再见

重点单词   查看全部解释    
visibility [.vizi'biliti]

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n. 能见度

 
flame [fleim]

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n. 火焰,热情
v. 燃烧,面红,爆发

 
reaction [ri'ækʃən]

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n. 反应,反作用力,化学反应

联想记忆
liquid ['likwid]

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adj. 液体的,液态的
n. 液体

 
colorless ['kʌləlis]

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adj. 无色的,苍白的

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describe [dis'kraib]

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vt. 描述,画(尤指几何图形),说成

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solution [sə'lu:ʃən]

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n. 解答,解决办法,溶解,溶液

联想记忆
soaked [səukt]

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adj. 湿透的 动词soak的过去式和过去分词

 
sensitive ['sensitiv]

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adj. 敏感的,灵敏的,易受伤害的,感光的,善解人意的

联想记忆
jar [dʒɑ:]

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n. 不和谐,刺耳声,震动,震惊,广口瓶
vi

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