《那些古怪又讓人憂心的問題》第13期:瘋狂電吹風
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．如果把電吹風放在一個密封的一米見方的鐵盒子裏，並且讓它不停地吹，會發生什麼？A. A TYPICAL HAIR DRYER draws 1875 watts of power.
A．一個普通的電吹風功率是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.
這1875瓦總得有個地方去。無論盒子裏發生了什麼，只要有1875焦耳的電能被消耗掉了，那麼最終就會產出1875焦耳的熱能。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.
對於所有使用電能的設備來說都是如此，懂得這一點會很方便。比如說，有人會擔心插在插座上的充電器（沒有連充電設備）會浪費電，那麼他們的擔憂是正確的嗎？根據熱交換你可以得出一個簡單的經驗法則：如果一個不在充電的充電器摸起來不是很暖手，那麼它一天消耗的電費不會超過一美分。而對於一個智能手機充電器來說，如果它摸起來不暖手，那麼它一年所消耗的電力價值不會超過一美分。對於幾乎所有的電力設備來說，這都適用But back to the box.
現在回過頭來再來看這個盒子。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.
熱量會從電吹風中流出並進入盒子。假設電吹風堅固無比，那麼盒子的內表面會一直升溫，直到外表面的溫度達到60℃。在這個溫度下，盒子散發熱量的速度正好和電吹風發出熱量的速度相等，於是整個系統便進入了平衡狀態。It's warmer than my parents! It's my new parents.
比我爸媽還溫暖哎，你是我的新家長啦！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.
如果盒子外面有一點微風，或者盒子放在潮溼表面或金屬表面上，那麼它散發熱量的速度會更快，平衡溫度會因此降低一些。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.
如果盒子是金屬做的，那麼只要你敢把手放在這60℃的表面5秒以上，那麼你的手一定會被燙傷。如果是木頭做的，雖然你可以摸得時間會更長些，但是電吹風出風口對着的那部分木頭有着火的危險。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.
盒子的內部就像烤箱一樣。裏面的溫度高低取決於盒壁的厚度，盒壁越厚或者絕熱性越好，溫度就能升得更高。其實不用很厚的盒子就能產生足夠的高溫燒燬電吹風了。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.
但我們不妨假設電吹風不可摧毀。如果我們真有這麼酷的電吹風，只調到1875瓦的功率真是太看不起它了。當18750焦耳的能量流出電吹風之後，盒子的表面將會達到200℃，和一個用中低火燒的平底鍋的溫度差不多。I wonder how high this dial goes.
我很想知道這個轉盤最高能轉到多少。There's a distressing amount of space left on the dial.
錶盤上還空着很多位置呢。The surface of the box is now 600°C, hot enough to glow a dim red.
現在盒子表面的溫度已經達到600℃，足以讓它放出黯淡的紅光。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.
如果盒子是鋁製的，那麼它的內部已經開始融化了。如果它是鉛質的，那麼它的外表面將開始熔化。如果把它放在木頭地板上，那整幢房子已經燒起來了。但我們不管周圍發生了什麼，我們的電吹風是不可摧毀的。Two megawatts pumped into a laser is enough to destroy missiles.
如果你把2兆焦耳（2×106焦耳）的能量注入激光的話，它已經足以摧毀導彈了。At 1300°C, the box is now about the temperature of lava.
現在溫度達到了1300℃，盒子已經和熔岩差不多熱了。One more notch.
能不能再給力一點？This hair dryer is probably not up to code.
這臺電吹風估計已經不符合規範了。Now 18 megawatts are flowing into the box.
盒子裏已經流入了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.
盒子表面的溫度已經達到了2400℃。如果盒子是鐵質的，那麼它早已經熔化了。如果它是由鎢之類的材料製成的，也許還能撐更長的時間。Just one more, then we'll stop.
再調高一次功率我們就收手。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）的功率足以讓盒子發出白光。沒有多少種材料製成的盒子能承受這樣的高溫，所以我們得假設盒子也是不可摧毀的。The floor is made of lava.
地面已成一片岩漿。Unfortunately, the floor isn't.
不幸的是，地板不是不可摧毀的。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.
但在它燒穿地板之前，有個人在它底下扔了個裝滿水的氣球。水蒸氣產生的衝擊力會把盒子炸飛到外面的人行道上。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.
功率達到1875兆瓦（收手什麼的是騙你的啦）。如果《回到未來》這部電影中說的是真的，電吹風已經產生了足夠回到過去的功率。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.
現在盒子發出的光線足以亮瞎你的雙眼，而且由於其釋放出來的巨大熱量，你只能待在數百米之外。盒子周圍是越變越大的岩漿池，任何距離50～100米之間的物體都燃起了熊熊大火。熱量和煙塵直衝雲霄，盒子底部的氣體不斷爆炸讓盒子飛上了天。它在哪裏掉下來，哪裏就開始着火，並形成新的岩漿池。We keep turning the dial.
我們繼續轉動旋鈕。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.
瘋狂電吹風功率已經達到18.7吉瓦（18.7×109瓦）！盒子周圍的環境已經接近航天飛機發射時發射架底板附近的環境了。盒子開始在它自己形成的強烈上升氣流中上下翻騰。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．威爾斯在他的著作《獲得自由的世界》中假想了像現在這個樣子的一個裝置。他描述說那是一種炸彈，它不是隻爆炸一次，而是不停地爆炸，就像在城市中心地帶引起無法撲滅的大火緩緩燃燒的煉獄一樣。這個故事預見了30年後原子彈的誕生。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.
盒子現在在空中飛來飛去。一旦它接近地面，受到炙烤的地面產生的氣流又會將它送回空中。The outpouring of 1.875 terawatts is like a house-sized stack of TNT going off every second.
（1.875×1012瓦）的功率是什麼概念？想象一下每秒有一幢房子那麼大的TNT炸藥在你身邊爆炸的樣子。A trail of firestorms-massive conflagrations that sustain themselves by creating their own wind systems-winds its way across the landscape.
一連串的火焰風暴——大量的火焰產生的風力系統能夠維持其自身繼續燃燒下去——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：現在電吹風消耗的能量已經不可思議地超過了地球上所有其他電器消耗的能量總和。The box, soaring high above the surface, is putting out energy equivalent to three Trinity tests every second.
現在在高空中亂飛的盒子每秒放出的能量相當於每秒引爆3次“三位一體”核試。At this point, the pattern is obvious. This thing is going to skip around the atmosphere until it destroys the planet.
接下去會發生什麼已經顯而易見了。這玩意兒會在大氣層裏亂飛，直到最終毀掉地球。Let's try something different.
讓我們想想別的。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 . . .
當盒子經過加拿大北部時，我們將旋鈕調到零。隨着急速冷卻，盒子開始墜落，伴隨一股水汽落在大熊湖裏。In this case, that's 11 petawatts.
然後……功率調節旋鈕轉到了11拍瓦（11×1015瓦）。A brief story:
先講一個小故事：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.
人造物體最快速度的官方紀錄是由太陽神2號探測器創造的，它在圍繞太陽飛行時達到了每秒約70千米的速度。但是這一紀錄的真實持有者，可能是一個2噸重的金屬井蓋。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.
這個井蓋放在一口豎井的頂部，底下是洛斯阿拉莫斯國家實驗室的一個地下核爆測試地，而這次試驗是普拉姆勃勃行動（Operation Plumbbob）的一部分。當1千噸當量的核彈在底下爆炸後，這玩意兒事實上就變成了核能土豆加農炮，井蓋瞬間擁有了巨大的能量。裝在蓋子上的高速攝像機只來得及拍攝到一幀井蓋向上運動的圖像，然後它就消失了——這說明井蓋的移動速度最少是每秒66千米。人們再也沒能找到這個井蓋。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，但與人們普遍猜測的結果不同，井蓋不太可能進入太空。根據牛頓的近似衝擊深度算法，井蓋要麼由於與空氣撞擊而被徹底破壞，要麼就會因空氣阻力速度慢下來而掉回地球。當我們重新打開電吹風時，原本在湖水裏漂動的盒子也經歷了相似的過程，盒子底部熾熱的水蒸氣向外膨脹。隨着盒子飛到空中，整個湖泊的表層水都會汽化，而水蒸氣在巨量輻射的作用下轉變爲等離子體，從而使盒子進一步加速。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.
與之前和大氣層猛烈碰撞的井蓋不同，巨量的輻射會加熱井蓋周圍的空氣，形成一個不斷膨脹的等離子體氣泡，在這個氣泡中飛行阻力極小。盒子很輕鬆地就飛出了大氣層，繼續一路向外飛，看起來會逐漸從“第二個太陽”變成一顆“矮星”，並消失在我們的視野之外。加拿大西北地區大部分地方都會燃起熊熊大火，但地球不至於毀滅。However, a few may wish we hadn't.
不過，大概會有幾個人希望我們還不如毀滅了好。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． 只要你沒把充電器連上充電設備就行。因爲一旦充電器連上了某個設備，比如智能手機或筆記本電腦，那麼電力就會從牆裏通過充電器流入充電設備。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築裏，然後我提出一個我們該怎麼逃出去的想法，你最好忽略我。Q. Would dumping anti-matter into the Chernobyl reactor when it was melting down stop the meltdown?
Q．向切爾諾貝利反應堆裏倒反物質能夠阻止它熔燬嗎？——A．J．Q. Is it possible to cry so much you dehydrate yourself?
Q．哭多了會導致身體脫水嗎？——卡爾?維爾德穆特
