作者 noenergy (energy) 看板 Interdiscip 标题 [翻译]蜘蛛人要吃什麽当早餐？ 时间 Mon Feb 9 02:33:09 2015 == 图文版：http://quantucafe.blogspot.de/2015/02/blog-post_6.html == What does Spider-Man eat for breakfast? 蜘蛛人要吃什麽当早餐？ 作者／洛许(Mark Lorch,英国赫尔大学生物化学系讲座教授) 译／吴京 While stuck in a hotel room I got sucked into watching the 2002 Spider-Man movie. And it struck me that Peter Parker must have an enormously high-protein diet to generate all that spider silk he goes through. So being the geek that I am, I wondered what his protein consumption has to be to sustain his villain-beating lifestyle. 当我闷在某间饭店的客房时，2002年版的蜘蛛人电影让我看到入迷。一个想法闪入脑海：彼 得帕克一定得吃极大量的高蛋白质食物才能产出所有被他用掉的蜘蛛丝。身为一个科学宅， 我想知道他到底消化了多少蛋白质来维持这种打击犯罪的生活形态。 I think we can work it out with a bit of school-level physics, maths and some basic biochemistry. We will need to work out the strength of Spider-Man’s silk, calculate how much force Spider-Man would exert on the silk and then figure out how much and what kind of protein will be needed to enable Spider-Man to do his stunts. 我想凭着中学等级的物理、数学及生物化学的基础知识便可得到解答。我们要求出蜘蛛人的 丝有多强韧、计算蜘蛛人会施加多少力量在其丝上，之後就可得知让他飞檐走壁需要何种蛋 白质及其数量。 Let’s assume Spider-Man produces silk that has the same characteristics as dragline silk produced by the European garden spider Araneus diadematus. That means it ought to have tensile strength – which is the largest stress that a material can withstand before breaking – similar to that of a piano wire. 让我们假设蜘蛛人的丝和在欧洲很普遍的十字园蛛(Araneus diadematus)所吐出之曳引丝相 仿，也就是说丝的张力强度可比拟钢琴弦，张力强度(tensile strength)是指一个材料在被 拉断前所能承受的最大应力。 A piano wire has the tensile strength of 1.1 billion Pascals. Pascals is a unit of measure for pressure, which is force per unit area. According to Marvel’s directory, Spider-Man weighs 75kg. Applying Newton’s first law, we can figure out the downward force that Spider-Man exerts. It would be mass times the Earth’s gravitational acceleration, which works out to be about 735 Newtons. These two values allow us to calculate the cross-sectional area of spider silk by dividing the force exerted by the tensile strength of the silk. Without going into the tiny calculations, it turns out that Spider-Man could hang from the ceiling on silk that is less than 1mm thick. 一根钢琴弦的张力强度为11亿帕斯卡，帕斯卡是量测压力的单位，即每单位面积上的力。 根据漫威字典，蜘蛛人的体重为75公斤，再依牛顿第一运动定律，我们可以计算他所施加的 向下力道约为735牛顿，即体质量乘地球的重力加速度所得的质。 有了这两个数字後，我们用向下力道除以丝的张力强度，就可以算出丝的截面积。不用算得 太精准，结论是厚度不到1公厘的丝就可让蜘蛛人吊在天花板上。 Now we need to figure out how much volume this total silk fibre would represent, if Spider-Man’s pre-lunch world-saving session requires 100m of it. Silk is slight heavier than water, which means that 100m of the wire would weight about 87g. There is about 6g of protein in an egg. So it looks like Spidey only needs about 15 eggs for breakfast if he plans to use 100m of silk. That’s not too bad. 现在我们要来算算所有丝纤维相当於多少量了，如果蜘蛛人在午餐前这段拯救世界的班表中 需要100公尺的丝，而丝稍重於水，可算出100公尺的丝约为87公克。 每颗鸡蛋约有6公克的蛋白质，如此看来，如果蜘蛛人打算用100公尺的丝，他似乎只要吃约 15颗的鸡蛋，这看起来不算太糟。 But spider silk consists predominantly of a protein call fibroin. Proteins are made from different amino acids, and fibroin is about 42% glycine. While egg consists of just 10.7% glycine and serine (I’m counting serine because it can be easily converted to glycine). So really Spidey needs to consume four times more egg protein than the silk protein he plans to use. So actually he needs 60 eggs for his 100m of silk. 但蜘蛛丝的主要成份为一种特定的蛋白质，称为丝素蛋白(fibroin)。不同蛋白质由不同成 份的胺基酸组成，丝素蛋白中约有42%的甘胺酸(glycine)，鸡蛋则只含有10.7%的甘胺酸及 丝胺酸(serine)(我把丝胺酸纳入计算，因为它可以轻易地转变为甘胺酸)。所以事实上蜘蛛 人从鸡蛋摄取的蛋白质必须高於造丝所需的四倍以上，如此他实际上要吃60颗鸡蛋才能造出 100公尺的丝。 That’s not really the end of it either. After all what happens if he leaps from a building to save a falling Mary-Jane and deploys his webslingers to save the day, as he does about halfway through the movie. In the scene, Spidey leaps from the balcony and falls for seven seconds before his silk starts to arrest his fall. He has caught M-J so let’s say their combined weight is 125kg. How much silk is he going to need here? 然而故事还没结束，毕竟蜘蛛人还要从高楼上跳下去救玛丽珍并且射出保命蜘蛛网来转危为 安，电影演到一半时他就是这样干的。 在那一幕中，蛛仔从阳台跃出，经过7秒後蜘蛛丝才抑止了下坠之势。他还要抓着一个玛丽 珍，我们就说总重为125公斤好了。光这个动作就要多少蜘蛛丝啊？ From the time of Spidey’s fall, we can calculate that he fell about 240m (wow, that’s one high balcony). Plus, assuming the silk stretches to its maximum, a stopping distance, it will be a fall of about the height of the Eiffel Tower. The impact force on the silk rope as they slow down would be about 35 times their weight. 从蛛仔下坠的时间算来，大约是落下了240公尺(哇！好高的阳台！)。此外，假设蛛丝延伸 一段减速停止的距离才来到最大长度，这落下的距离就跟艾菲尔铁塔一般高了。为了缓冲下 坠而施加到丝索上的冲击力道则大约是35乘与他们的体重。 Which is about six times greater force than when Spidey is just hanging around on the end of his line of silk. But taking into account the length of the fall (240m) and the extra force, he will need 1.3 kg of silk to catch his fall. So I reckon he must have had about 900 eggs for breakfast that morning, just to have enough silk for that one scene. I think Aunt May might have noticed. 这比蛛仔吃饱太闲地悬挂在蜘蛛丝上的力量还要高出6倍(译注：(35*125)/(9.8*75)。把坠 落距离(240公尺)和额外力量一起考量，他需要1.3公斤的丝才能接住这次下坠。所以我估算 他那天早餐必须吃上900颗蛋才有足够的丝完成那一幕。我想梅婶应该早就注意到了吧！ 资料来源(Source of the materials)： http://theconversation.com/what-does-spider-man-eat-for-breakfast-36857 英文原文为The Conversation网站公开授权转载 == 译者部落格「吴京的量子咖啡馆」：http://quantucafe.blogspot.tw ※ 编辑: noenergy (141.70.179.19), 02/09/2015 02:33:09 ※ 编辑: noenergy (141.70.179.19), 02/09/2015 02:36:21 ※ 编辑: noenergy (141.70.179.19), 02/09/2015 02:38:18 ※ 编辑: noenergy (141.70.179.19), 02/09/2015 02:39:36