第7章 元素那些事 Elemental Matters · 第7讲S3

1. 老师，讲稿里说碳14测年法需要知道“目前的辐射程度”和“衰变速度”，这俩具体是指啥呀？是不是就是现在的含量和半衰期？
2. 为什么动植物活着的时候碳14能保持平衡，但一旦死了（比如树被砍下来）就不能补充了，这个补充机制到底是咋回事？
3. 文中提到卢瑟福测出的沥青油矿年龄是7亿年，而当时大多数人认为地球年龄没那么老，凯尔文算出来的是2400万年，这两个数据差别咋这么大？
4. 卢瑟福在皇家研究院演讲时为什么说话那么委婉谨慎？是因为凯尔文也在场，他怕直接反驳凯尔文的观点会得罪人吗？
5. 既然放射性发现了新的热源，为什么这就直接证明了地球比凯尔文算的2400万年要老得多？这个逻辑链条是咋连上的？

1. Teacher, the transcript says carbon-14 dating requires knowing 'current radiation levels' and 'decay rate'. What exactly do these mean? Are they just the current content and the half-life?
2. Why can carbon-14 stay balanced while plants and animals are alive, but stops being replenished once they die (like when a tree is cut down)? How does that replenishment mechanism actually work?
3. The text mentions Rutherford calculated the pitch blend's age at 700 million years, while most people at the time thought the Earth wasn't that old, and Kelvin calculated it at only 24 million years. Why is there such a huge difference between these figures?
4. Why was Rutherford so cautious and tactful when giving his lecture at the Royal Institution? Was it because Kelvin was present, and he didn't want to offend him by directly contradicting his views?
5. Since radioactivity revealed a new source of heat, why does that directly prove the Earth is older than Kelvin's 24 million years? How is that logical chain connected?

1 00:00:04,880 --> 00:00:08,440 By calculating backwards from how much radiation a 2 00:00:08,440 --> 00:00:12,260 material had now,and how swiftly it was decaying, 3 00:00:12,260 --> 00:00:13,740 you could work out its age. 4 00:00:14,400 --> 00:00:17,320 要算出一个事物的年龄, 5 00:00:17,400 --> 00:00:19,860 先要具备两个条件。 6 00:00:19,980 --> 00:00:23,800 首先你要知道 how much radiation a material had now, 7 00:00:23,940 --> 00:00:26,960 就这个物质目前的辐射程度是什么呀。 8 00:00:27,040 --> 00:00:30,840 第二个条件就是 how swiftly it was decaying, 9 00:00:30,860 --> 00:00:33,780 也就是它衰变的速度是什么呀。 10 00:00:33,780 --> 00:00:39,440 也就是说它的半衰期是什么那通过这两个信息我们再 11 00:00:39,440 --> 00:00:41,400 倒推 calculating backwards 12 00:00:41,880 --> 00:00:47,240 就可以算出事物的年龄了这举一个例子大家肯定都听 13 00:00:47,240 --> 00:00:52,720 说过碳 14 地年法就是考古界经常听到过的经常用来测 14 00:00:52,720 --> 00:00:53,860 定文物的年龄 15 00:00:54,560 --> 00:01:00,740 这是因为呢动植物活着的时候它体内的碳 14 虽然在不 16 00:01:00,740 --> 00:01:06,660 断的衰变之中但是也不断地在补充新的碳 14 所以它跟 17 00:01:06,660 --> 00:01:11,000 大气环境中的碳 14 比值是大致相同的 18 00:01:11,100 --> 00:01:16,000 但是动植物死掉以后就是比如说一棵树被砍下来做成 19 00:01:16,000 --> 00:01:16,800 家具以后 20 00:01:17,220 --> 00:01:23,860 它体内的碳 14 仍在进行衰变不断地减少但是不再获得 21 00:01:23,860 --> 00:01:30,740 补充所以我们现在算出它目前的碳 14 衰变的程度然后 22 00:01:30,740 --> 00:01:36,600 再根据它的半衰期就可以算出这个植物死亡的时间这 23 00:01:36,600 --> 00:01:39,600 样算出来的结果是相当准确的 24 00:01:40,320 --> 00:01:45,040 那用同样的办法可以算出任何一个石头的年龄形成的 25 00:01:45,040 --> 00:01:51,140 时间他测试了一块橙色的石头原来是橙色的石头他发 26 00:01:51,140 --> 00:01:57,140 现它是 700 万岁的石头非常年轻的石头 Most people 27 00:01:57,140 --> 00:01:59,360 were prepared to grant the earth 28 00:02:00,310 --> 00:02:05,480 卢瑟福就拿沥青油矿做了一个实验 Pitch blend 其中这 29 00:02:05,480 --> 00:02:09,990 个 pitch 就是沥青的意思这个沥青油矿并不是因为里 30 00:02:09,990 --> 00:02:16,110 面含有沥青而是它具有沥青的光泽这是提取油的最主 31 00:02:16,110 --> 00:02:21,170 要的矿物 The principal ore of uranium Ore 就是矿石 32 00:02:21,170 --> 00:02:23,810 Principle 最主要的 And 33 00:02:24,100 --> 00:02:28,580 finally to be 700 million years old 他测出来的结果就 34 00:02:28,580 --> 00:02:34,160 是这块石头是有 7 亿年 very much older than the age most 35 00:02:34,160 --> 00:02:38,160 people were prepared to grant the earth to grant means 36 00:02:38,160 --> 00:02:43,800 to give in a formally matter 就是非常正式的授予所以 37 00:02:43,800 --> 00:02:48,880 他算出来的这颗沥青油矿的年龄高达 7 亿年这比当时 38 00:02:48,880 --> 00:02:53,760 绝大多数人所认为的地球的年龄都要长得多 in the 39 00:02:53,760 --> 00:02:58,540 spring of 1904 Rutherford traveled to London to give a 40 00:02:58,540 --> 00:03:00,460 lecture at the Royal Institution, 41 00:03:00,720 --> 00:03:04,980 the August organization founded by Count von Rumford, 42 00:03:05,240 --> 00:03:07,400 only 105 years before. 43 00:03:07,680 --> 00:03:12,760 Though that powdery and per iwigged age now seemed a 44 00:03:12,760 --> 00:03:13,800 distant aeon, 45 00:03:13,960 --> 00:03:17,620 compared with the royal sleeves up robustness of the 46 00:03:17,620 --> 00:03:18,700 late Victorians." 47 00:03:18,980 --> 00:03:25,980 1904 年春天卢瑟福前往伦敦去皇家研究院进行演讲这 48 00:03:25,980 --> 00:03:29,840 位这个 Royal Institution 就是 The August 49 00:03:29,840 --> 00:03:34,080 Organization founded by Count Von Romford Only 105 50 00:03:34,080 --> 00:03:35,000 years ago 51 00:03:35,100 --> 00:03:40,700 仅仅是 105 年前由这位 Count Von Romford 建立的一个 52 00:03:40,700 --> 00:03:42,020 August Organization 53 00:03:42,580 --> 00:03:45,900 August means impressive and respected 54 00:03:46,540 --> 00:03:49,540 大家肯定觉得他很面熟如果大写的话, 55 00:03:49,640 --> 00:03:50,740 这不就是八月吗? 56 00:03:50,800 --> 00:03:52,340 确实就是同一个词, 57 00:03:52,440 --> 00:03:57,020 其实八月这个名称是来自 August us Caesar, 58 00:03:57,240 --> 00:03:59,820 就是奥古斯都凯撒的称号。 59 00:04:00,140 --> 00:04:03,340 August us,他的本意就是神圣伟大的, 60 00:04:03,600 --> 00:04:06,480 而这位 August us Caesar, 61 00:04:06,660 --> 00:04:09,200 其实他的原名是乌大维, 62 00:04:09,320 --> 00:04:11,860 是罗马帝国的第一任皇帝, 63 00:04:11,940 --> 00:04:15,480 也就是我们平常说的凯撒大帝的侄孙, 64 00:04:15,600 --> 00:04:17,080 不是他本人。 65 00:04:17,080 --> 00:04:22,840 这位乌大维是被元老院赐封为 August us 这个称号就是 66 00:04:22,840 --> 00:04:27,780 August us Though that powdery and per iwicked age Now 67 00:04:27,780 --> 00:04:32,950 seemed a distant e on A distant e on means a distant age 这 68 00:04:32,950 --> 00:04:37,280 个 e on 我们见过多次了上次讲那个地质年代的时候说 69 00:04:37,280 --> 00:04:39,800 过这个 e on 就是 period 或者 age 70 00:04:40,280 --> 00:04:42,640 Powdery 就是涂脂抹粉的 71 00:04:43,140 --> 00:04:46,960 而这个 per iwicked 就是戴假发的 The 72 00:04:47,500 --> 00:04:53,440 Royal Institution 是仅仅 105 年前创立的在创立之初 73 00:04:53,440 --> 00:04:59,060 当时的人们是脸上涂着粉头上戴着假发那个年代现在 74 00:04:59,060 --> 00:05:04,860 看来仿佛非常的遥远尤其是跟现在一对比现在的社会 75 00:05:04,860 --> 00:05:08,340 风气可不是这样的了现在是 Royal Sleeves of 76 00:05:08,340 --> 00:05:12,800 Robustness of the Late Victorians Robustness 形容词 77 00:05:12,800 --> 00:05:16,640 是 robust 意思是健壮有力的充满生命力的 78 00:05:17,280 --> 00:05:21,080 Vict orians 维多利亚时代的后期 79 00:05:21,620 --> 00:05:26,400 那个时候呢是大家都是一副撸起袖子加油干的一副很 80 00:05:26,400 --> 00:05:31,380 健壮的这种形象跟以前图纸模粉戴着个沉重的甲犯那 81 00:05:31,380 --> 00:05:32,620 完全是不一样的 82 00:05:33,220 --> 00:05:36,600 我们现在说一下这个 Late Victorians 尤其是这个 83 00:05:36,600 --> 00:05:41,120 Victorian 其实以前也讲过维多利亚时代被认为是英 84 00:05:41,120 --> 00:05:47,040 国工业革命的顶峰时期也是英国经济文化的全盛时期 85 00:05:47,040 --> 00:05:49,820 当时英国的经济占到了全球的 70 86 00:05:51,790 --> 00:05:57,530 当时维多利亚时代科学发明浪潮是汹涌澎湃人们信仰 87 00:05:57,530 --> 00:06:03,130 科学进步对于工业革命是充满了乐观和信心气船的出 88 00:06:03,130 --> 00:06:09,090 现使得运输和贸易达到了前所未有的繁荣兴旺四通八 89 00:06:09,090 --> 00:06:15,030 达的铁路又贯穿东西南北所以当时这个社会是充满着 90 00:06:15,030 --> 00:06:20,540 活力的 Rutherford was there to talk about his new 91 00:06:20,540 --> 00:06:24,240 disintegration theory of radioactivity as part of 92 00:06:24,240 --> 00:06:26,800 which he brought out his piece of pitch blend 93 00:06:27,550 --> 00:06:31,590 这个 disintegration 也是衰变的意思因为这个 94 00:06:31,590 --> 00:06:36,690 integrate 大家如果知道这个词的话 integrate 是 I N T E 95 00:06:36,690 --> 00:06:42,910 G R A T Eintegrate 意思是把它结合在一起那么 96 00:06:42,910 --> 00:06:49,350 disintegrate 这个前序表示否定结合在一 ……（后略，完整文稿见视频页字幕）