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为什么永动机是不可能的?

发布者: 五毒 | 发布时间: 2022-11-24 21:48| 查看数: 33| 评论数: 0|



Around 1159 A.D., a mathematician called Bhaskara the Learned sketched a design for a wheel containing curved reservoirs of mercury.

大约在公元1159年, 一位名叫Bhaskara the Learned的数学家为一个装有弯曲汞储罐的轮子设计了草图。

He reasoned that as the wheels spun, the mercury would flow to the bottom of each reservoir,

他认为,当车轮旋转时, 汞会流到每个容器的底部,

leaving one side of the wheel perpetually heavier than the other.

从而使车轮的一侧永远比另一侧重,

The imbalance would keep the wheel turning forever.

将使车轮永远转动。

Bhaskara's drawing was one of the earliest designs for a perpetual motion machine,

Bhaskara的图纸是永动机的最早设计之一,

a device that can do work indefinitely without any external energy source.

该装置可以在没有任何外部能源的情况下无限期工作。

Imagine a windmill that produced the breeze it needed to keep rotating.

想象一下,一台风车产生了保持旋转所需的风力,

Or a lightbulb whose glow provided its own electricity.

或是一个永远亮着的灯泡。

These devices have captured many inventors' imaginations because they could transform our relationship with energy.

许多发明家为此绞尽脑汁,因为它可以改变我们与能源的关系。

For example, if you could build a perpetual motion machine that included humans as part of its perfectly efficient system,

比如说,如果我们能造出一台永动机,并将人类作为其高效系统的一部分,

it could sustain life indefinitely.

那永生就不再是梦了。

There's just one problem.

但只有一个问题。

They don't work.

永动机是不可能的。

Ideas for perpetual motion machines all violate one or more fundamental laws of thermodynamics,

所有有关永动机的想法都违背了至少一条热力学基本定律,

the branch of physics that describes the relationship between different forms of energy.

热力学是描述不同形式能量之间关系的物理学分支。

The first law of thermodynamics says that energy can't be created or destroyed.

热力学第一定律是,能量不会凭空产生或消失。

You can't get out more energy than you put in.

你不可能从机器里得到比投入时更多的能量。

That rules out a useful perpetual motion machine right away because a machine could only ever produce as much energy as it consumed.

这就排除了任何永动机的可行性,因为一台机器最多只能产生和它消耗的同样多的能量。

There wouldn't be any left over to power a car or charge a phone.

不可能还有多余的能量用来驱动车或者给手机充电。

But what if you just wanted the machine to keep itself moving?

但是如果你只是想让机器自己不停地运行下去呢?

Inventors have proposed plenty of ideas.

发明家们想出了很多点子。

Several of these have been variations on Bhaskara's over-balanced wheel with rolling balls or weights on swinging arms.

其中一些是Bhaskara的超平衡车轮的变体, 带有滚动球或摆臂上的配重,

None of them work.

但是没一种有用。

The moving parts that make one side of the wheel heavier also shift its center of mass downward below the axle.

移动的部分确实让轮子的一端更重一些,但同时将轮子整体的重心降低到轮轴以下。

With a low center of mass, the wheel just swings back and forth like a pendulum, then stops.

在低重心时,轮子只会像钟摆一样前后摆动,最终停下来。

What about a different approach?

换一种思路呢?

In the 17th century, Robert Boyle came up with an idea for a self-watering pot.

在17世纪,罗伯特·波义尔想出了个点子,一种自己给自己浇水的壶。

He theorized that capillary action, the attraction between liquids and surfaces that pulls water through thin tubes,

他的理论认为,毛细作用,即液体和表面之间的吸引力 ,使水穿过细管,

might keep the water cycling around the bowl.

这样也许能使水不断围绕壶做循环运动。

But if the capillary action is strong enough to overcome gravity and draw the water up, it would also prevent it from falling back into the bowl.

但是如果毛细作用大到足以克服重力,并可以把水从管中吸上来,那它也应该能阻止水再落回到壶中。

Then there are versions with magnets, like this set of ramps.

再后来,又有了一些带有磁铁的永动机装置,比如这套斜坡装置。

The ball is supposed to be pulled upwards by the magnet at the top, fall back down through the hole, and repeat the cycle.

小球应该会被顶端的磁铁吸引上斜坡,然后从洞中掉回底部,循环往复。

This one fails because like the self-watering pot, the magnet would simply hold the ball at the top.

这个装置也没能成功,就像之前所说的能给自己浇水的水壶,磁铁只可能把小球吸在顶部不动。

Even if it somehow did keep moving, the magnet's strength would degrade over time and eventually stop working.

即使小球能不断运动,磁铁的磁力也会随着时间流逝而消退,最终停止运行。

For each of these machines to keep moving, they'd have to create some extra energy to nudge the system past its stopping point,

对于所有的这些机器,如果想要保持运动,它们必然需要产生一些额外的能量,将整个系统推过静止点,

breaking the first law of thermodynamics.

这就违反了热力学第一定律。

There are ones that seem to keep going, but in reality, they invariably turn out to be drawing energy from some external source.

有一些永动机看上去会一直运行下去,但事实上,它们总归会从外界获取额外的能量。

Even if engineers could somehow design a machine that didn't violate the first law of thermodynamics,

即使工程师们能够以某种方式造出不违反第一定律的永动机,

it still wouldn't work in the real world because of the second law.

由于第二定律,它仍旧不可能实现。

The second law of thermodynamics tells us that energy tends to spread out through processes like friction.

热力学第二定律告诉我们能量总是通过某些方式散失,比如摩擦。

Any real machine would have moving parts or interactions with air or liquid molecules that would generate tiny amounts of friction and heat,

任何现实生活中的机器都有着移动的部件,或者是与气体及液体分子互相作用,这就会产生微量的摩擦与热量,

even in a vacuum.

即使在真空中也是如此。

That heat is energy escaping, and it would keep leeching out,

那些热量就是能量损失,并且它一直在流失,

reducing the energy available to move the system itself until the machine inevitably stopped.

不断地减少可供系统自身运动的能量,直到机器不可避免地停下来。

So far, these two laws of thermodynamics have stymied every idea for perpetual motion and the dreams of perfectly efficient energy generation they imply.

到目前为止,这两条热力学定律已经排除了任何关于永动机的设想,以及100%效率产能的可能。

Yet it's hard to conclusively say we'll never discover a perpetual motion machine because there's still so much we don't understand about the universe.

但是,这并不能绝对地说我们将永远无法找到永动机,因为我们对整个宇宙的了解还是太少了。

Perhaps we'll find new exotic forms of matter that'll force us to revisit the laws of thermodynamics.

也许我们将找到一种新奇的物质存在形式,让我们不得不重新审视热力学定律。

Or maybe there's perpetual motion on tiny quantum scales.

又或许在极小的量子尺度会有永动机的存在。

What we can be reasonably sure about is that we'll never stop looking.

我们能确定的是我们永远不会停止寻找。

For now, the one thing that seems truly perpetual is our search.

现在,唯一看上去“永动”的,是我们的搜寻。


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