When you think of Archimedes' "Eureka!" moment, you probably think of this. As it turns out, it may have been more like this. In the third century BC, Hieron, king of the Sicilian city of Syracuse, chose Archimedes to supervise an engineering project of unprecedented scale. Hieron commissioned a sailing vessel 50 times bigger than a standard ancient warship, named the Syracusia after his city. Hieron wanted to construct the largest ship ever, which was destined to be given as a present for Egypt's ruler, Ptolemy. But could a boat the size of a palace possibly float? In Archimedes's day, no one had attempted anything like this. It was like asking, "Can a mountain fly?" King Hieron had a lot riding on that question. Hundreds of workmen were to labor for years on constructing the Syracusia out of beams of pine and fir from Mount Etna, ropes from hemp grown in Spain, and pitch from France. The top deck, on which eight watchtowers were to stand, was to be supported not by columns, but by vast wooden images of Atlas holding the world on his shoulders. On the ship's bow, a massive catapult would be able to fire 180 pound stone missiles. For the enjoyment of its passengers, the ship was to feature a flower-lined promenade, a sheltered swimming pool, and bathhouse with heated water, a library filled with books and statues, a temple to the goddess Aphrodite, and a gymnasium. And just to make things more difficult for Archimedes, Hieron intended to pack the vessel full of cargo: 400 tons of grain, 10,000 jars of pickled fish, 74 tons of drinking water, and 600 tons of wool. It would have carried well over a thousand people on board, including 600 soldiers. And it housed 20 horses in separate stalls. To build something of this scale, only for that to sink on its maiden voyage? Well, let's just say that failure wouldn't have been a pleasant option for Archimedes. So he took on the problem: will it sink? Perhaps he was sitting in the bathhouse one day, wondering how a heavy bathtub can float, when inspiration came to him. An object partially immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. In other words, if a 2,000 ton Syracusia displaced exactly 2,000 tons of water, it would just barely float. If it displaced 4,000 tons of water, it would float with no problem. Of course, if it only displaced 1,000 tons of water, well, Hieron wouldn't be too happy. This is the law of buoyancy, and engineers still call it Archimedes' Principle. It explains why a steel supertanker can float as easily as a wooden rowboat or a bathtub. If the weight of water displaced by the vessel below the keel is equivalent to the vessel's weight, whatever is above the keel will remain afloat above the waterline. This sounds a lot like another story involving Archimedes and a bathtub, and it's possible that's because they're actually the same story, twisted by the vagaries of history. The classical story of Archimedes' Eureka! and subsequent streak through the streets centers around a crown, or corona in Latin. At the core of the Syracusia story is a keel, or korone in Greek. Could one have been mixed up for the other? We may never know. On the day the Syracusia arrived in Egypt on its first and only voyage, we can only imagine how residents of Alexandria thronged the harbor to marvel at the arrival of this majestic, floating castle. This extraordinary vessel was the Titanic of the ancient world, except without the sinking, thanks to our pal, Archimedes.
當你想到阿基米德的 「我發現了!」靈機一動的瞬間, 你或許會想阿基米德定律 是在這樣的情況下發現的。 真實的故事,可能是另外一回事。 西元前三世紀,赫農王 是西拉克斯西西里城的國王, 指定阿基米德監督 一個史無前例的工程專案。 赫農王要求阿基米德建造一艘 比戰艦還要大 50 倍的帆船, 並以其城市命名為西拉克斯。 赫農王要建造一艘前所未有的大船, 要作為埃及統治者 托勒密的禮物。 但像宮殿一樣大的船浮得起來嗎? 在阿基米德那個年代, 沒有人解決過這樣的問題。 這就像是在問 「能讓一座山飛起來嗎?」 赫農王對這個問題也感到疑問。 數百名工人花了好幾年的時間 建造西拉克斯 以埃特納火山的松樹 和杉木來作船樑。 使用西班牙的大麻作成麻繩, 使用來自法國的樹脂。 甲板上有八座瞭望臺, 不是以圓柱撐起來, 而是傳說中將世界扛在肩上的 阿特拉斯的巨大木製人像。 船頭上, 巨大的彈射器能夠發射 180 磅的石彈。 為了讓乘客享受搭乘的樂趣, 這帆船特別作一條雕花長廊步道, 一座室內游泳池, 提供熱水浴的澡堂, 一座充满書籍和雕像的圖書館, 一座供奉女神愛芙羅黛蒂的神殿, 和一座健身房。 除此之外,還要找一些 更加困難的差事給阿基米德, 赫農王想要將帆船裝滿貨物: 四百噸的穀物, 一萬罐的醃魚, 七十四噸的飲用水, 六百噸的羊毛。 這船必須能夠搭載一千位以上的乘客, 其中包括六百位士兵。 可在不同的馬廄安置二十匹馬。 為了建造一艘龐大的船, 因為如此, 它的處女航就沈沒在大海裡? 嗯,也就是說失敗的結果 對阿基米德來說並不是 他想要的作法。 他提出了問題:這艘船會沈嗎? 有一天他坐在澡堂裡, 很想知道如何讓一個浴缸浮起來, 一個靈感突然浮現腦海。 一個物體的一部分浸入液體會有浮力 這浮力等於物體排出的液體的重量。 換句話說,如果一艘二千噸的西拉克斯 所排出的水量也正好是二千噸, 它剛好可以浮起來。 如果可以排出四千噸的水, 要船浮起來是沒問題的。 如果只排出一千噸的水 是浮不起來的, 當然,赫農王對此結果會不高興。 這就是浮力定律, 工程師仍然稱它為阿基米德定律。 它解釋為何一艘超級鋼製油輪 能夠像木造划艇般容易浮起來 浴缸也是相同的道理。 若船龍骨線以下所排出的水的重量 等於船的重量, 船龍骨線以上的地方 將保持浮在船的吃水線之上。 這聽起來像是另一個故事, 有別於阿基米德和浴缸的故事, 也可能是因為 它們是同一個故事, 卻被異想天開的歷史故事所扭曲。 大家所知的阿基米德靈機一動的故事! 「大喊我發現了」然後裸奔穿過 圍繞著皇冠的街道中心, 皇冠的拉丁文是"corona"。 西拉克斯故事的主旨是船龍骨, 其西臘文是"korone"。 是因為把 "corona" 和 "korone" 混淆了嗎? 我們不得而知。 當西拉克斯在它的第一次 也是唯一一次的航行抵達埃及時, 我們只能想像亞歷山大的居民 蜂擁至港口 看到這雄偉的,飄浮的城堡 的到來而感到驚訝。 這艘特別的船是 古文明世界的鐵達尼號, 但這艘船並有沈入大海, 這要歸功於阿基米德。