《那些古怪又让人忧心的问题》第13期:疯狂电吹风
HAIR DRYER
Q. What would happen if a hair dryer with continuous power were turned on and put in an airtight 1 × 1 × 1-meter box?
Q．如果把电吹风放在一个密封的一米见方的铁盒子里，并且让它不停地吹，会发生什么？A. A TYPICAL HAIR DRYER draws 1875 watts of power.
A．一个普通的电吹风功率是1875瓦。
All 1875 watts have to go somewhere. No matter what happens inside the box, if it's using 1875 watts of power, eventually there will be 1875 watts of heat flowing out.
这1875瓦总得有个地方去。无论盒子里发生了什么，只要有1875焦耳的电能被消耗掉了，那么最终就会产出1875焦耳的热能。This is true of any device that uses power, which is a handy thing to know. For example, people worry about leaving disconnected chargers plugged into the wall for fear that they're draining power. Are they right? Heat flow analysis provides a simple rule of thumb: If an unused charger isn't warm to the touch, it's using less than a penny of electricity a day. For a small smartphone charger, if it's not warm to the touch, it's using less than a penny a year. This is true of almost any powered device.
对于所有使用电能的设备来说都是如此，懂得这一点会很方便。比如说，有人会担心插在插座上的充电器（没有连充电设备）会浪费电，那么他们的担忧是正确的吗？根据热交换你可以得出一个简单的经验法则：如果一个不在充电的充电器摸起来不是很暖手，那么它一天消耗的电费不会超过一美分。而对于一个智能手机充电器来说，如果它摸起来不暖手，那么它一年所消耗的电力价值不会超过一美分。对于几乎所有的电力设备来说，这都适用But back to the box.
现在回过头来再来看这个盒子。Heat will flow from the hair dryer out into the box. If we assume the dryer is indestructible, the interior of the box will keep getting hotter until the outer surface reaches about 60°C (140°F). At that temperature, the box will be losing heat to the outside as fast as the hair dryer is adding it inside, and the system will be in equilibrium.
热量会从电吹风中流出并进入盒子。假设电吹风坚固无比，那么盒子的内表面会一直升温，直到外表面的温度达到60℃。在这个温度下，盒子散发热量的速度正好和电吹风发出热量的速度相等，于是整个系统便进入了平衡状态。It's warmer than my parents! It's my new parents.
比我爸妈还温暖哎，你是我的新家长啦！The equilibrium temperature will be a bit cooler if there's a breeze, or if the box is sitting on a wet or metallic surface that conducts away heat quickly.
如果盒子外面有一点微风，或者盒子放在潮湿表面或金属表面上，那么它散发热量的速度会更快，平衡温度会因此降低一些。If the box is made of metal, it will be hot enough to burn your hand if you touch it for more than five seconds. If it's wood, you can probably touch it for a while, but there's a danger that parts of the box in contact with the mouth of the hair dryer will catch fire.
如果盒子是金属做的，那么只要你敢把手放在这60℃的表面5秒以上，那么你的手一定会被烫伤。如果是木头做的，虽然你可以摸得时间会更长些，但是电吹风出风口对着的那部分木头有着火的危险。The inside of the box will be like an oven. The temperature it reaches will depend on the thickness of the box wall; the thicker and more insulating the wall, the higher the temperature. It wouldn't take a very thick box to create temperatures high enough to burn out the hair dryer.
盒子的内部就像烤箱一样。里面的温度高低取决于盒壁的厚度，盒壁越厚或者绝热性越好，温度就能升得更高。其实不用很厚的盒子就能产生足够的高温烧毁电吹风了。But let's assume it's an indestructible hair dryer. And if we have something as cool as an indestructible hair dryer, it seems like a shame to limit it to 1875 18,750 watts flowing out of the hair dryer, the surface of the box reaches over 200°C (475°F), as hot as a skillet on low-medium.
但我们不妨假设电吹风不可摧毁。如果我们真有这么酷的电吹风，只调到1875瓦的功率真是太看不起它了。当18750焦耳的能量流出电吹风之后，盒子的表面将会达到200℃，和一个用中低火烧的平底锅的温度差不多。I wonder how high this dial goes.
我很想知道这个转盘最高能转到多少。There's a distressing amount of space left on the dial.
表盘上还空着很多位置呢。The surface of the box is now 600°C, hot enough to glow a dim red.
现在盒子表面的温度已经达到600℃，足以让它放出黯淡的红光。If it's made of aluminium, the inside is starting to melt. If it's made of lead, the outside is starting to melt. If it's on a wood floor, the house is on fire. But it doesn't matter what's happening around it; the hair dryer is indestructible.
如果盒子是铝制的，那么它的内部已经开始融化了。如果它是铅质的，那么它的外表面将开始熔化。如果把它放在木头地板上，那整幢房子已经烧起来了。但我们不管周围发生了什么，我们的电吹风是不可摧毁的。Two megawatts pumped into a laser is enough to destroy missiles.
如果你把2兆焦耳（2×106焦耳）的能量注入激光的话，它已经足以摧毁导弹了。At 1300°C, the box is now about the temperature of lava.
现在温度达到了1300℃，盒子已经和熔岩差不多热了。One more notch.
能不能再给力一点？This hair dryer is probably not up to code.
这台电吹风估计已经不符合规范了。Now 18 megawatts are flowing into the box.
盒子里已经流入了18×106焦耳的能量。The surface of the box reaches 2400°C. If it were steel, it would have melted by now. If it's made of something like tungsten, it might conceivably last a little longer.
盒子表面的温度已经达到了2400℃。如果盒子是铁质的，那么它早已经熔化了。如果它是由钨之类的材料制成的，也许还能撑更长的时间。Just one more, then we'll stop.
再调高一次功率我们就收手。This much power-187 megawatts-is enough to make the box glow white. Not a lot of materials can survive these conditions, so we'll have to assume the box is indestructible.
187兆瓦（187×106瓦）的功率足以让盒子发出白光。没有多少种材料制成的盒子能承受这样的高温，所以我们得假设盒子也是不可摧毁的。The floor is made of lava.
地面已成一片岩浆。Unfortunately, the floor isn't.
不幸的是，地板不是不可摧毁的。Before it can burn its way through the floor, someone throws a water balloon under it. The burst of steam launches the box out the front door and onto the sidewalk.
但在它烧穿地板之前，有个人在它底下扔了个装满水的气球。水蒸气产生的冲击力会把盒子炸飞到外面的人行道上。We're at 1.875 gigawatts (I lied about stopping)rding to Back to the Future, the hair dryer is now drawing enough power to travel back in time.
功率达到1875兆瓦（收手什么的是骗你的啦）。如果《回到未来》这部电影中说的是真的，电吹风已经产生了足够回到过去的功率。The box is blindingly bright, and you can't get closer than a few hundred meters due to the intense heat. It sits in the middle of a growing pool of lava. Anything within 50–100 meters bursts into flame. A column of heat and smoke rise high into the air. Periodic explosions of gas beneath the box launch it into the air, and it starts fires and forms a new lava pool where it lands.
现在盒子发出的光线足以亮瞎你的双眼，而且由于其释放出来的巨大热量，你只能待在数百米之外。盒子周围是越变越大的岩浆池，任何距离50～100米之间的物体都燃起了熊熊大火。热量和烟尘直冲云霄，盒子底部的气体不断爆炸让盒子飞上了天。它在哪里掉下来，哪里就开始着火，并形成新的岩浆池。We keep turning the dial.
我们继续转动旋钮。At 18.7 gigawatts, the conditions around the box are similar to those on the pad during a space shuttle launch. The box begins to be tossed around by the powerful updrafts it's creating.
疯狂电吹风功率已经达到18.7吉瓦（18.7×109瓦）！盒子周围的环境已经接近航天飞机发射时发射架底板附近的环境了。盒子开始在它自己形成的强烈上升气流中上下翻腾。In 1914, H. G. Wells imagined devices like this in his book The World Set Free. He wrote of a type of bomb that, instead of exploding once, exploded continuously, a slow-burn inferno that started inextinguishable fires in the hearts of cities. The story eerily foreshadowed the development, 30 years later, of nuclear weapons.
1914年，H．G．威尔斯在他的著作《获得自由的世界》中假想了像现在这个样子的一个装置。他描述说那是一种炸弹，它不是只爆炸一次，而是不停地爆炸，就像在城市中心地带引起无法扑灭的大火缓缓燃烧的炼狱一样。这个故事预见了30年后原子弹的诞生。The box is now soaring through the air. Each time it nears the ground, it superheats the surface, and the plume of expanding air hurls it back into the sky.
盒子现在在空中飞来飞去。一旦它接近地面，受到炙烤的地面产生的气流又会将它送回空中。The outpouring of 1.875 terawatts is like a house-sized stack of TNT going off every second.
（1.875×1012瓦）的功率是什么概念？想象一下每秒有一幢房子那么大的TNT炸药在你身边爆炸的样子。A trail of firestorms-massive conflagrations that sustain themselves by creating their own wind systems-winds its way across the landscape.
一连串的火焰风暴——大量的火焰产生的风力系统能够维持其自身继续燃烧下去——在地球表面肆虐。A new milestone: The hair dryer is now, impossibly, consuming more power than every other electrical device on the planet combined.
新的里程碑：现在电吹风消耗的能量已经不可思议地超过了地球上所有其他电器消耗的能量总和。The box, soaring high above the surface, is putting out energy equivalent to three Trinity tests every second.
现在在高空中乱飞的盒子每秒放出的能量相当于每秒引爆3次“三位一体”核试。At this point, the pattern is obvious. This thing is going to skip around the atmosphere until it destroys the planet.
接下去会发生什么已经显而易见了。这玩意儿会在大气层里乱飞，直到最终毁掉地球。Let's try something different.
让我们想想别的。We turn the dial to zero as the box is passing over northern Canada. Rapidly cooling, it plummets to Earth, landing in Great Bear Lake with a plume of then . . .
当盒子经过加拿大北部时，我们将旋钮调到零。随着急速冷却，盒子开始坠落，伴随一股水汽落在大熊湖里。In this case, that's 11 petawatts.
然后……功率调节旋钮转到了11拍瓦（11×1015瓦）。A brief story:
先讲一个小故事：The official record for the fastest manmade object is the Helios 2 probe, which reached about 70 km/s in a close swing around the Sun. But it's possible the actual holder of that title is a two-ton metal manhole cover.
人造物体最快速度的官方纪录是由太阳神2号探测器创造的，它在围绕太阳飞行时达到了每秒约70千米的速度。但是这一纪录的真实持有者，可能是一个2吨重的金属井盖。The cover sat atop a shaft at an underground nuclear test site operated by Los Alamos as part of Operation Plumbbob. When the 1-kiloton nuke went off below, the facility effectively became a nuclear potato cannon, giving the cap a gigantic kick. A high-speed camera trained on the lid caught only one frame of it moving upward before it vanished-which means it was moving at a minimum of 66 km/s. The cap was never found.
这个井盖放在一口竖井的顶部，底下是洛斯阿拉莫斯国家实验室的一个地下核爆测试地，而这次试验是普拉姆勃勃行动（Operation Plumbbob）的一部分。当1千吨当量的核弹在底下爆炸后，这玩意儿事实上就变成了核能土豆加农炮，井盖瞬间拥有了巨大的能量。装在盖子上的高速摄像机只来得及拍摄到一帧井盖向上运动的图像，然后它就消失了——这说明井盖的移动速度最少是每秒66千米。人们再也没能找到这个井盖。Now, 66 km/s is about six times escape velocity, but contrary to common speculation, it's unlikely the cap ever reached space. Newton's impact depth approximation suggests that it was either destroyed completely by impact with the air or slowed and fell back to we turn it back on, our reactivated hair dryer box, bobbing in lake water, undergoes a similar proces. The heated steam below it expands outward, and as the box rises into the air, the entire surface of the lake turns to steam. The steam, heated to a plasma by the flood of radiation, accelerates the box faster and faster.
每秒66千米差不多是逃逸速度的6倍，但与人们普遍猜测的结果不同，井盖不太可能进入太空。根据牛顿的近似冲击深度算法，井盖要么由于与空气撞击而被彻底破坏，要么就会因空气阻力速度慢下来而掉回地球。当我们重新打开电吹风时，原本在湖水里漂动的盒子也经历了相似的过程，盒子底部炽热的水蒸气向外膨胀。随着盒子飞到空中，整个湖泊的表层水都会汽化，而水蒸气在巨量辐射的作用下转变为等离子体，从而使盒子进一步加速。Rather than slam into the atmosphere like the manhole cover, the box flies through a bubble of expanding plasma that offers little resistance. It exits the atmosphere and continues away, slowly fading from second sun to dim star. Much of the Northwest Territories is burning, but the Earth has survived.
与之前和大气层猛烈碰撞的井盖不同，巨量的辐射会加热井盖周围的空气，形成一个不断膨胀的等离子体气泡，在这个气泡中飞行阻力极小。盒子很轻松地就飞出了大气层，继续一路向外飞，看起来会逐渐从“第二个太阳”变成一颗“矮星”，并消失在我们的视野之外。加拿大西北地区大部分地方都会燃起熊熊大火，但地球不至于毁灭。However, a few may wish we hadn't.
不过，大概会有几个人希望我们还不如毁灭了好。1 Though not necessarily those plugged into a second device. If a charger is connected to something, like a smartphone or laptop, power can be flowing from the wall through the charger into the device.
1． 只要你没把充电器连上充电设备就行。因为一旦充电器连上了某个设备，比如智能手机或笔记本电脑，那么电力就会从墙里通过充电器流入充电设备。2 Note: If you're ever trapped with me in a burning building, and I suggest an idea for how we could escape the situation, it's probably best to ignore me.
2． 注意：如果你某天和我一起被困在着火的建筑里，然后我提出一个我们该怎么逃出去的想法，你最好忽略我。Q. Would dumping anti-matter into the Chernobyl reactor when it was melting down stop the meltdown?
Q．向切尔诺贝利反应堆里倒反物质能够阻止它熔毁吗？——A．J．Q. Is it possible to cry so much you dehydrate yourself?
Q．哭多了会导致身体脱水吗？——卡尔?维尔德穆特
