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Hi, I'm Jessica
嗨，我是Jessica
and today I'm gonna be talking about a chemical demonstration
今天我要讲的化学演示
I like to call the steaming gun
叫作蒸汽枪
So you've probably seen this before at the drugstore or in your house
你们在药店或是家里可能见过这个
It's called hydrogen peroxide and it's the stuff you put on cuts
它叫过氧化氢，可以用于伤口消毒
but it has many other uses as well
它还有很多其它用途
from bleaching things, to powering rockets
包括漂白，为火箭提供动力等
depending on its concentration
具体用途取决于它的浓度
The solution that you get at the drugstore is usually 3%
药店出售的溶液浓度通常是3%
So it's called hydrogen peroxide
这是过氧化氢
And its chemical formula is H202
其化学式是H2O2
So the atoms are arranged like this
原子是这样排列的
It sort of looks like water
它和水有些像
but the extra oxygen makes the molecule more reactive
但多出来的氧原子让分子反应活性更强
Now if you leave it alone, it decomposes into water and oxygen
把它放在那里，它会分解为水和氧气
The equation looks like this
方程式是这样的
I'm going to balance it
我来配平
And normally you can't see this reaction happening
通常你看不到这个反应发生
because at room temperature, it's very slow
因为室温下，反应很慢
but there are many ways to speed it up
但为反应提速的方法有很多
like increasing the temperature or adding a catalyst
例如提高温度，或加入催化剂
In this demonstration, MIT's Dr. John Dolhun uses
这个演示中 MIT的John Dolhun博士
catalyst to make the reaction go thousands of times faster than normal
将使用催化剂让反应比正常情况快数千倍
Let's watch
我们看看吧
So we're gonna do this experiment here
这里我们将做这个实验
and basically what we've got is we've got four bottles
这里我们有四个瓶子
we're each gonna do the experiment
我们两人会做这个实验
In the bottle, we've got out 15 mils of hydrogen peroxide here
瓶中，我们有15毫升过氧化氢
And we're going to be using a man-made catalyst
我们将使用一种人造催化剂
We're going to be using manganese dioxide
我们用到的是二氧化锰
We're each gonna take a scoop of this
我们两个人都将取一勺这个
and we're going to put it in
放入到瓶子中
You can set it down on the tray
你可以把它放到盘子上来
and just, it's starting to work
它开始反应了
You won't have to stand up to see this
你们不需要站起来看
It's you can start to see some condensed water vapor
这里会开始有一些凝结的水蒸气
forming inside the bottle
产生于瓶中
Oxygen bubbles are coming out
氧气泡泡开始鼓出
Now we're just gonna lightly hold that
我们将轻轻地捏它
OK, so what happened?
这里发生了什么
