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化学大冒险

MIT's Choose-Your-Own: Chemistry Adventure

惠特妮(主持人):这是双氧水
WHITNEY: So this is hydrogen peroxide.
你可能在你的急救箱里见过它
You might recognize it from your first aid kit,
因为它能很好地杀菌
because it’s really good at killing germs.
但是双氧水的的用途远不止清洗伤口
But there’s more to this guy than cleaning cuts.
事实上 这种液体的组成成分
So this liquid is actually made up
是时刻准备分裂的分子们
of molecules that are constantly wanting to break apart.
过氧化氢 或者说H2O2分子
Hydrogen peroxide, or H2O2, is held together
以不稳定的化学键连接—— 就是这个 在两个氧原子之间
by an unstable bond– this one, between the oxygen atoms.
所以过氧化氢分子时刻想着分裂
So the molecule wants to break down
变成两个更小 更稳定的部分——H2O 或者说水
into smaller, more stable pieces– H2O, or water,
和O2 或者说氧气
and O2, or oxygen gas.
现在这种分裂太慢了
Now this breakdown is usually so slow,
我们甚至看不到它的反应情况
we can’t even see it happening.
但是如果我们想要看到具体反应 又应该怎么做呢?
But what if we did want to see it happen?
我们可以用来酵母急剧加快这个反应
We can speed up this reaction a lot by using yeast.
酵母能够生成氧化氢酶 这使得
Yeast makes something called catalase, and what this does
过氧化氢的分解加速
is speed up the breakdown of hydrogen peroxide,
加速化学反应的物质
and something that speeds up a chemical reaction
我们叫做催化剂
is called a catalyst.
酵母能够产生过氧化氢酶 因为
And the reason yeast makes catalase is because hydrogen
过氧化氢能够损坏细胞和DNA
peroxide damages cells and DNA.
所以过氧化氢酶四处游荡 分解过氧化氢
So the catalase goes around and breaks apart hydrogen peroxide,
所以过氧化氢不能伤害酵母
so it can’t damage the yeast.
其实我们的身体里面也有过氧化氢酶
And actually our bodies have catalase too,
来保护我们的细胞和DNA
to protect our cells and DNA.
最酷的是过氧化氢酶
And the cool thing is the catalase
在整个化学反应过程之后不会发生改变
doesn’t get used up at all in the process.
所以它能够一遍遍游荡 分解
So it keeps going around, breaking apart
过氧化氢 快速释放氧气和水
the hydrogen peroxide, quickly releasing oxygen gas and water.
通常氧气直接
And normally this oxygen gas would just
释放到空气中 但是为了加点乐子 我们
get released out into the air, but for fun, we
可以把氧气存到肥皂泡中
can trap it in soap bubbles.
这是双氧水 你可以在药店里买到它
This is the hydrogen peroxide you can buy at the drugstore.
它浓度不高
It’s not very strong.
只有3%
It’s only 3%.
不过这个是30%浓度的
But this one is 30%.
现在我用水把它稀释到12%
I’m diluting this down with water to 12%,
在加上一毫升洗涤剂 和一点食用色素
mixing one milliliter of dish soap, and some food coloring.
我也会加一克酵母来激活反应
I’m also taking a gram of yeast and activating it
这一克酵母会混合四毫升热水
with four milliliters of warm water.
所以把这些混合之后 你觉得会发生什么呢?
So what do you think will happen if we mix all these together?
很酷
So pretty cool.
但是 我们能够得到更多泡沫吗?
But can we get even more foam?
我们能够加速反应吗?
Can we make it faster?
让我们每次稍微调整反应物的一小部分
Let’s tweak each of the ingredients one at a time
看看我们能够怎么影响反应
and figure out how they affect the reaction.
我们应该改变过氧化氢的量
Should we change the amount of hydrogen peroxide,
洗涤剂的量 还是酵母的量?
the amount of soap, or the amount of yeast?

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