BBC化学史观后感

BBC化学史观后感

1807年,康沃尔郡化学家戴维,利用最新发现的电来电解碱金属化学品苛性钾发现一种新的元素——极活泼的钾。

世界有何构成? 万物皆由92种元素组成。

一个叫Jim Al-khalili 的人,一生都在研究物理学,但是如果没有破解物质之谜的化学家的工作的话,就不能获得亚原子世界的知识。

寻找元素及了解其性质是科学史中最具有侦察性的故事之一,这是非常困难的任务,跨越了几个世纪的时间。科学家们都用自己的生命去探索自然世界。

人类对元素的迷恋造就了现代世界,并把人类推到毁灭的边缘。

发现元素

爆炸——人类不惜一切代价寻找答案,寻求重要的真理——这种难以抑制的冲动,推动了科学的发展。

如果我们不了解世界,不知道世界是由什么组成的,这是难以想象的,人们为火着迷,如果不知道氧气使火点着,甚至是否存在氧。不知道氢是海水的重要成分,或者钠和氯化合成得到盐味。

只有到了最近的200年,我们才知道元素是什么。元素是一种物质,在化学反应中不能分解成更简单的成分。

古希腊人就已经知道铅、铜、金、银、铁、汞和锡,但希腊

人认为这些只是金属,希腊人深信,世界由土、空气、火和水组成。

之后的1000多年,人类没找到破解自然界的方法,只好把元素的概念局限于身边能够看到的事物。直到16世纪,情况才开始改变。炼金师了解身边的物质,有意把碱金属变成金,他们用神秘的代码和符号,对实验现象作了记录。

后来,一个名叫帕拉塞尔苏斯的人,他不仅是一个破解物质之谜的炼金师,他也是物理学家和外科医生,提出了一个新结论:世界由三种元素组成,即盐、硫和汞。他认为这三种元素是制造金属和药物的主要成分。用有毒的汞提取金。

1669年,在昏暗、有臭味的汉堡地下室,波兰特相信尿提取金将是伟大的发现,他只需要50桶尿,他找到了尿的核心,他将尿蒸馏成糊状,然后再高温下加热几天,最后一缕缕烟表明它能在空气中自燃。但这种提取出来的物质不是金,而是磷。在化学生物中,磷是非常重要的,人体的骨骼主要由磷酸钙组成,人体内有很多磷,DNA和人体各种组织中都有磷,血液中有磷,多余的磷会转移到尿中。

1677年,磷被送进了宫廷,波义耳决定研究其性质。 德国化学家约翰内斯.贝歇耳提出,获得破坏力是由于无形物引起的,称为燃素。燃素是无色无味的轻物质,它能使物体燃烧使物体还原到其真实的形式。木头燃烧变成灰,所以木材是由灰、纯木和燃素组成的。在空气中没有燃素,普利斯特发现并称

之为脱燃素空气。

法国科学家,拉瓦锡(化学之父)发现了一种新的方法,他宣称,他发现了氧这一新的元素。这一新发现最终证明希腊的四元素说是错误的。

化学步入现代化时期,在该时期,化学家分解物质,获得大发现努力了解世界的组成。但是,化学家的发现没有规律和逻辑,只是化学世界中的随机元素。

拉瓦锡首先定义了元素,现有化学方法无法再分解的物质,他开始列出所有的元素。现在,33种元素代替了4种,这就是拉瓦锡得出的元素的原始列表,他把元素分成了四类,即气体、非金属、金属和土。气体有氢气和氧气。他并没有全对,他认为光和热是气体元素。我们现在知道光和热只是能量。

早期认为,元素或许是有规律的,构成世界的物质,有某些主要的模式,拉瓦锡建立了一个系统对其他化学家的发现进行分类,并开始改变化学语言、科学词汇的革命,图画和诗意变得精确。脱燃素空气变成氧气、止血剂氧化黄变成氧化铁、硫酸盐的油变成硫酸、达观毛料变成氧化锌……终于有通用的语言来定义元素了。

这些奇异的名字被替换有些可惜,但拉瓦锡的逻辑真的令人崇拜。他促使了化学革命,但是其他革命也将到来。

1794年5月8日,拉瓦锡被带到法国的革命广场,所有人在35分钟内被处决,第二天,法国数学家约瑟夫.拉格朗日评论

此事时说:砍下拉瓦锡的头颅,只需要一息的功夫,但是要产生这样一个头颅则需要100年。拉瓦锡留下了宝贵的遗产,他摒弃了旧教条代之以实验方法。

实验能够证实或反驳最激进的观点,但科学家依然相信还有更多的元素有待发现,努力找到新方法来找到元素。物质基本上还是无法识破的,物质需要更强大和危险的力量才会被分解。

 

第二篇:BBC蓝色星球纪录片英文观后感

The review of the blue planet by BBC

Our earth actually is a blue planet, which is covered with 71 percent of the world by brine. How vast such superficial content! Therefore, the mysterious field is composed of

numerous parts, such as various marine animals and many different plants. This means a truth that we can’t neglect the effects alerted on the ocean by the creature and some terrestrial beings along the coast.

Food links, complex food net, describe relationship running through the animal-kinds, from plankton to the hugest sort, blue whale, approximately. To my surprise, blue whales, such a formidable giant, rely on millions of krill. Such gargantuan harvests depend on the continuing fertility of the ocean. There exists much amazing association between two species like this. Generally, grey whales are much bigger than killer whales. But 15 killer whales can trace an adult female grey whale several kilometers just for her baby. They chase the young until he can’t swim any longer because of toil. Whales breathe with lung, as is known. These killer whales try their best to press the baby grey whale to make his head in the sea. At last, the young whale dies of oxygen-poor. His mother can not do anything about it and continue her journey north for food, leaving the child’s body behind. She has no choice to give up the one who she had conceived for thirteen months. Moreover, the living in the water is usually classified according to their ambient living

environment. In the abyssal area, large ranks of transparent lives lead a rich and varied life. Among the group, imitation is a necessary skill to confuse the enemy and attain what they want. These guys may imitate the surroundings or just copy the color around them. Some fish have special luminous organs, which function as viewfinders, hiding in the dark. They reflect the weak blue light from water surface and slightly disappear along with it. Some striped mullets and jellyfish have the ability to flash like neon light. Their motion is

excellent in disguise. Most of them move slowly relatively. As the depth rises, the quantity of living grow gradually with the sunlight brightening and energy strengthened.

In the shallow sea, battles happen every day almost. Various animals join in the cruel conflict. As is commonly seen, bands of sardines used to take action together for safety. It’s not, nevertheless, an ideal method. Bottlenose dolphin and whales unintentionally work in conjunction with each other. Dolphins are in charge of getting the sardines apart, making use of waves foam. Whales can enjoy the dish much more easily. Smart seabirds fly low, pressing close to the water, to find the best location to seize the prey. After that, they rush into the water like spurting arrow. The hunters grab their relish to the habitat. Meantime, besides food link, there coexists symbiosis. Sea-gull and half-moon can help other fish by cleaning the mould on the cover.

What is vividly introduced above occurs in the diverse layers, while the layers are not alone, in touch with each other instead. Ocean current becomes the key factor to mix the brine from distinct areas. Nutrition blends to a new balance. Of course, this results in energetic fishing ground. Fish shuttle up and down, making water world filled with vitality and more oxygen dissolved.

The ocean is an organic whole in the long term, in spite of the pole and equator. Low degree represents a flinty challenge in the pole. Even an animal of large scale may face fatal attacks thanks to the jam resulting from the freezing cold weather. Near an ice hole lives a polar bear. Through the hole, white whales keep breathing during the past half year. The bear obtain some trophies by overwhelming these whales trapped in the hole. Harp seals give birth to their babies on the ice pieces, partly due to that reason. Coming to the next summer, generations fly back from the south. Guillemots nested on the cliff that bears and foxes are unable to reach. Fortunately, guillemots can haunt between sky and sea water. About on June, ice layer begin to melt. Many cracks emerge, which benefits the marine animals that need oxygen. Melting provide an access to cods for white whales. Autumn arrives, sea starts freezing again until November. On the opposite pole, situation precisely is on the contrary. Here dwell penguins. Surrounded by Antarctic Ocean, the continent gets rid of bears’ threatening, supplying penguins with solution to leisure. High temperature causes creature diversity, to some degree. In the tropic and sub-tropic, plants rank from algae to mangrove. The trait offers an important place for the beings to reside and frolic. Moon gravity plays a significant role in the forming of tide and tsunami. Coral reef improves the sea bed into a perfect harbor for different organism. Along with the rising tide, turtles land on some islands to lay eggs and crabs get out of the sand to search for animalcule to eat. Shellfish can come and go free. But it’s a tragedy that shellfish occasionally change into a delicious feast for others. Flounder, kite-shaped, always gets help from tide and wave and glides at pleasure. The strongest tide arrives after new moon, caused by sun gravity together with moon gravity. Sea bed expose in the air. Raccoons look for suitable food there, the best outcome is crab. At the same time, tide is the good timing for fishes to mate and accomplish fertilization and breeding.

But global changes now threaten the great blooms of plankton on which the whales depend. Once, and not so long ago, 300,000 blue whales roamed the oceans. Now, less than 3% of that number remains. Our planet is still full of wonders. As we explore them, so we gain not only understanding, but power. It’s not just the future of the whale that today lies in our hands. It’s the survival of the natural world in all parts of the living planet. We can now destroy or we can cherish. The choice is ours.

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