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火是固体,液体,还是气体?

Is fire a solid, a liquid, or a gas? - Elizabeth Cox

Sitting around a campfire, you can feel its heat,
围坐在火堆旁 你能感受到它的炽热
smell the woody smoke, and hear it crackle.
闻到木材燃烧的烟味 听到木材的爆裂声
If you get too close, it burns your eyes and stings your nostrils.
如果你再靠近点 火会烧到眼睛 呛到鼻孔
You could stare at the bright flames forever
你可以永远盯着明亮的火焰
as they twist and flicker in endless incarnations.
因为它们在无尽的化身中摇曳闪烁
But what exactly are you looking at?
但你到底在看什么呢
The flames are obviously not solid,
火焰显然不是固体
nor are they liquid.
也不是液体
Mingling with the air, they’re more like a gas,
与空气混合 火焰更像气体
but more visible–and more fleeting.
但却更明显 更短暂
And on a scientific level, fire differs from gas
在科学层面 火不同于气体
because gases can exist in the same state indefinitely
因为气体可以无限地以相同的状态存在
while fires always burn out eventually.
而火最终总会燃尽
One misconception is that fire is a plasma,
有一种误解 认为火是一种等离子体
the fourth state of matter in which atoms
物质的第四种状态
are stripped of their electrons.
即 原子从电子中剥离
Like fire and unlike the other kinds of matter,
像火 不像其他物质
plasmas don’t exist in a stable state on earth.
等离子体在地球上不是以稳定状态存在的
They only form when gas is
只有当气体暴露于电场
exposed to an electric field or superheated
或被加热到数万度时
to temperatures of thousands or tens of thousands of degrees.
等离子体才会存在
By contrast, fuels like wood and paper burn
相比之下 木材和纸之类的燃料
at a few hundred degrees —far below the
在几百度的温度下就会燃烧
threshold of what’s usually considered a plasma.
远低于等离子体的阈值
So if fire isn’t a solid, liquid, gas,
那么 如果火不是固体 液体 气体
or a plasma, what does that leave?
或等离子体 那它是什么呢
It turns out fire isn’t actually matter at all. Instead,
结果证明 火根本不是物质 相反
it’s our sensory experience of a
火是一种叫做“燃烧”的化学反应的
chemical reaction called combustion.
感觉体验
In a way,
在某种程度上
fire is like the leaves changing color in fall,
火就像秋天变色的树叶
the smell of fruit as it ripens,
就像水果成熟时的芳香
or a firefly’s blinking light.
或萤火虫闪烁的光
All of these are sensory clues that a
所有这些都是正在发生的化学反应
chemical reaction is taking place.
感觉暗示
What differs about fire is that it engages a lot of
火的不同之处在于
our senses at the same time, creating the kind of vivid
它同时调动我们的多种感觉
experience we expect to come from a physical thing.
创造了一种我们所期望的生理上的生动体验
Combustion creates that sensory experience
燃烧使用燃料 热量和氧气
using fuel, heat, and oxygen.
创造了那种感觉体验
In a campfire,
在火堆中
when the logs are heated to their ignition temperature,
当木材被加热至燃点时
the walls of their cells decompose,
它们的细胞壁会分解
releasing sugars and other molecules into the air.
向空气中释放糖分以及其他分子
These molecules then react with airborne oxygen
然后这些分子与氧气反应
to create carbon dioxide and water.
生成二氧化碳和水
At the same time, any trapped water in the logs vaporizes,
同时 木材里存集的水分蒸发
expands, ruptures the wood around it,
使水四周的木材发生膨胀破裂
and escapes with a satisfying crackle.
以一声清脆悦耳的破裂声逃离
As the fire heats up, the carbon dioxide and water vapor
随着火苗温度的升高 二氧化碳和水蒸气
created by combustion expand.
也由燃烧的持续而产生
Now that they’re less dense, they rise in a thinning column.
现在它们不那么浓密 会以薄的圆柱形上升
Gravity causes this expansion and rising, which gives
地心引力使它们扩散 上升
flames their characteristic taper.
赋予了火焰特有的烛芯
Without gravity, molecules don’t separate
如果没有地心引力 分子不会根据密度分离开
by density and the flames have a totally different shape.
火焰也会有完全不同的形状
We can see all of this because combustion also generates light.
我们之所以能看到火 是因为燃烧也产生光
Molecules emit light when heated,
当分子被加热时 会发出光茫
and the color of the light depends on the temperature of the molecules.
其颜色取决于分子的温度
The hottest flames are white or blue.
最强烈的火焰是白色或蓝色
The type of molecules in a fire can also influence flame color.
火焰中分子的类型也能影响其颜色
For instance, any unreacted carbon atoms from the logs
例如 任何未反应的木材里的碳原子
form little clumps of soot that rise
形成小块的烟灰
into the flames and emit the yellow-orange light,
上升到火焰里 发出橘黄色的光
we associate with a campfire.
我们就和营火在一起了
Substances like copper, calcium chloride,
类似于铜 氯化钙 氯化钾的物质
and potassium chloride can add their own characteristic hues to the mix.
能增添自己的特有色调来混合
Besides colorful flames, fire also continues to generate heat as it burns.
除了多彩的火焰 火随着燃烧继续产生热量
This heat sustains the flames by keeping
通过燃料的不停加入 或 保持燃点温度
the fuel at or above ignition temperature.
这种热量支撑着火焰
Eventually though, even the hottest fires run out of fuel or oxygen.
最终 即使最炽热的火焰也会耗尽燃料或氧气
Then,those twisting flames give a final hiss
那时 这些摇曳的火焰发出最后的嘘声
and disappear with a wisp of smoke
随着一缕烟消散
as if they were never there at all.
好像从未存在过一样

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视频概述

火就不是固体 也不是液体或者气体 它是一种化学反应的感觉体验

听录译者

收集自网络

翻译译者

呵呵呵呵

审核员

审核员 V

视频来源

https://www.youtube.com/watch?v=YV8TT9LRBrY

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