Solid, liquid, gas and … plasma? - Michael Murillo

743,276 views ・ 2015-07-28

TED-Ed


请双击下面的英文字幕来播放视频。

翻译人员: Sanqiang Xiao 校对人员: Gabriella Hu
00:08
Have you ever seen static electricity cause a spark of light?
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你曾经见过静电引起的火花吗?
00:12
What is that spark?
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这个火花是什么呢?
00:14
What about lightning,
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闪电又是什么呢?
00:15
the Northern Lights,
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北极光
00:17
or the tail of a comet?
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又或者是彗尾呢?
00:19
All of those things, and many others,
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事实上,所有这些现象以及宇宙中其他类似现象中
00:21
in fact 99.9% of the universe, are made of plasma.
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99.9%都是由等离子体产生的
00:27
Plasma is a state of matter
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等离子体是物质的一种状态
00:29
drastically different from the more familiar forms.
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与我们所熟悉的其他物质状态极其不同
00:32
Take ice, for example.
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以冰为例
00:34
Ice, a solid, melts to become water, a liquid,
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固态冰受热融化为液态水
00:38
which, when heated, vaporizes into steam, a gas.
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液态水受热蒸发为水蒸气
00:42
Continued heating of the steam at a high enough temperature
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继续加热水蒸气至足够高的温度
00:46
causes the water molecules in it to separate
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会使其中的水分子分解为
00:49
into freely roaming hydrogen and oxygen atoms.
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可以自由移动的氢原子和氧原子
00:53
With a little more heat, the ionization process occurs
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再给予少量的热量 离子化过程就发生了
00:57
and the negatively charged electrons escape the atoms,
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带负电的电子逃离原子
01:00
leaving behind positively charged ions.
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从而留下带正电的离子
01:04
This mixture of freely roaming negative and positive charges is plasma,
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这种能够自由移动的,带有正负电荷的 离子混合物就是等离子体
01:09
and at a high enough temperature, any gas can be made into one.
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在足够高的温度下 任何气体都能转变为等离子体
01:14
These freely moving charged particles behave very differently
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这些自由移动的带电粒子
与组成其他物质状态的粒子的行为很不一样
01:18
from the particles in other types of matter.
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01:21
When a doorknob, a solid, has static electricity on it,
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当一个固态的门把手携带了静电
01:25
it doesn't look or behave any differently.
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它并不会有太大的不同
01:28
And with the exception of a compass or other magnetic object,
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除了指南针和其他磁体
01:31
we rarely see matter respond to a magnetic field.
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我们很少看到物质受到磁场的影响
01:36
But put a plasma in an electric field or magnetic field,
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但是如果等离子体被置于电场或者磁场之中
01:40
and you'll get a very different reaction.
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它们会产生非常不同的反应
01:42
Because plasmas are charged,
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因为等离子体中的离子带有电荷
01:44
electric fields accelerate them,
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电场会对它们进行加速
01:46
and magnetic fields steer them in circular orbits.
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而磁场会驱使它们形成圆周轨道
01:50
And when the particles within plasma collide,
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当等离子体中的粒子发生碰撞
01:52
or accelerated by electricity or magnetism,
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或者被电场或磁场加速时
01:56
light is generated,
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光就产生了
01:58
which is what we see when we look at plasmas
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这也就是我们所观察等离子体时所看到的,
02:00
like the Aurora Borealis.
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比如北极光
02:03
Plasmas aren't just beautiful, celestial phenomena, though.
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但是等离子体不仅仅是绚丽的天空现象
02:06
Imagine a tiny cube made of normal gas with a very high voltage across it.
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想象一下,一个装有正常气体的小方块 被高电压贯穿
02:12
The resulting electric field
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高电压产生电场
02:14
pushes some of the electrons off the atoms and accelerates them to high speeds
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电场驱使电子从原子脱离 然后使电子具有很高的速度
02:19
causing the ionization of other atoms.
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并使其他原子也离子化
02:22
Imbedded impurities in the tiny cube of gas
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气体中夹杂的杂质
02:26
cause it to gain and release a precise amount of energy
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会使气体以紫外线辐射的方式
02:30
in the form of ultraviolet radiation.
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吸收和释放一定量的能量
02:34
Attached to each tiny cube,
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每个小立方体的表面上附着有荧光物质
02:36
a fluorescent material glows with a specific color
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当紫外线以适当的强度激发它们时
02:40
when ultraviolet light at just the right intensity reaches it.
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荧光物质就会发出特定颜色的光
02:45
Now, make a rectangle out of a million of these tiny cubes,
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现在我们用一百万个这样的小立方体组成一个长方形
02:49
each separately controlled by sophisticated electronics.
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每个立方体都由复杂的电子元件控制着
02:53
You may be looking at one now.
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这就是等离子电视
02:55
This is called a plasma TV.
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你现在可能正在看它
02:58
Plasmas also have implications for health care.
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等离子体对人体健康也有积极影响
03:01
Plasma chemists create highly specific plasmas
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等离子化学家制造特定的等离子体
03:05
that can destroy or alter targeted chemicals,
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这种等离子体能够消除或者替换目标化学物
03:09
thereby killing pathogenic organisms on food or hospital surfaces.
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从而杀死食物中或医院里各种表面上的病原体
03:14
Plasmas are all around us,
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等离子体无处不在
03:17
in forms that are both spectacular and practical.
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它既壮观绚丽又真实存在
03:20
And in the future, plasma could be used
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未来,等离子体能够使我们
03:22
to permanently rid landfills of their waste,
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永久地摆脱垃圾填埋
03:25
efficiently remove toxins from our air and water,
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它能有效地清除空气和水中的毒素
03:28
and provide us with a potentially unlimited supply
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为我们提供一种潜在的用之不竭的
03:32
of renewable clean energy.
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可再生的清洁能源
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