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你知道世界上什么最小吗

来源: 作者: 2019-11-10 02:28:19

在萌娃百出的《爸爸去哪儿》中,Jasper和嗯哼一直都在为谁更大而争论不休!是不是萌翻啦!而我们今天要讨论的话题则是谁更小。大家认为这个世界上什么最小呢?是蚂蚁?大海边散落的沙粒?还是空气中漂浮的灰尘?在很久之前,无论是哲学家还是科学家对这一问题都表现出了极大的兴趣。大家普遍认为物质是可以被分割,至到一个基本的单位为止。因此,关于物质是由离散单元组成并且能够被任意分割的概念流传了上千年,但这些想法只是基于抽象的、哲学的推理,而非实验和实证观察。

你知道世界上什么最小吗

在我国的历史上,也不乏科学家和哲学家对这一问题的思考。例如,早在战国时期,我国哲学家惠施就曾说过:“一尺之棰,日取其半,万世不竭。”表明了物质无限可分的观点。我国另一位伟大的哲学家墨子在其著作《墨经》中也独立提出了物质有限可分的概念,并将最小的可分单位称之为“端”。

你知道世界上什么最小吗

现存最早关于原子的概念阐述可以追溯到公元前6世纪的古印度。正理派和胜论派发展了一种完备的理论来描述原子是如何组成更加复杂的物体(首先成对,然后三对再结合)。西方的文献则要晚一个世纪,是由留基伯提出,他的学生德谟克利特总结了他的观点。大约在公元前450年,德谟克利特创造了原子这个词语,意思就是不可切割。尽管印度和希腊的原子观仅仅是基于哲学上的理解,但现代科学界仍然沿用了由德谟克利特所创造的名称。

因此,无论中外,大家普遍认为我们的大千世界是由一种非常非常小的且不可再分割的粒子构成的,我们无法用肉眼所看到它们,它们确与每样事物发生相互作用,构成了大千世界。可是,我们怎样才能看到它们并且证明它们的存在呢?

你知道世界上什么最小吗

1785年,荷兰科学家扬·英格豪斯正在研究一个他无法理解的奇怪现象。在他的实验室里,煤粉中的一种微小粒子在酒精表面乱飞。大约50年后的1827年,苏格兰植物学家罗伯特·布朗也描述过与之相似的情况。在他将显微镜对准花粉粒时,发现一些花粉粒释放出微小粒子,这些粒子随机地四散开去。

起初,布朗怀疑这些粒子是某种未知的微生物。于是,他用其他物质(如岩石尘埃这样的无机物)替代花粉粒重新进行实验。然而,他看到了相同的奇怪运动。

科学地解释这一现象用了将近一个世纪。爱因斯坦发展出一套数学公式,能够预测这一特定类型的运动。后来,这种不规则的运动被命名为布朗运动。爱因斯坦的理论认为,这些来自花粉粒的粒子之所以动个不停,是因为它们在不停地与成千上万个微小的水分子相互碰撞,这些分子是由原子构成的。

至到1908年,经过计算验证的观测实验证实了原子的真实存在。10年之内,物理学家进行了更进一步的研究。通过分离单个原子,人们才越来越了解原子的内部结构。

现在我们来听听Aaron老师的讲解吧!

友情提示:建议小伙伴们横屏放大看视频,以便清晰阅读字幕哦!

那么,究竟什么是原子?它真的只是一个普通的很小的粒子吗?在历史上,科学家围绕着它又有哪些争论和不同的见解呢?让我们一起期待下一次的物理课吧!

文字详解

课程文字版详解在此!!错过 Aaron 老师的课程视频或者想要详细了解课堂内容的小伙伴们,千万不要错过哦!!

Hey guys! So much in the same way that we started the last series by asking some questions about what is light. We're gonna start this series by asking some questions about what is anything. So let's say for example you say what is the difference between the skin on my arm and a rockthat may seeminitially (乍看)obvious. You say why a rock is a rock and the skin on my arm is skin. But what does that statement actually mean? What if we have metals? What's the difference between metals and a rock? We know that you have a metal likecopper(铜)oraluminum (铝).You canbend (使弯曲)it. You can if you are strong enoughstretch it (延展它)twist it (扭曲它)and it wouldn't break. But if you did that with arock it's gonnashatter (碎裂). Maybe I don't know if everyone's done this. But I remember as a kid throwing rocks off of a bridge into a lake sometimes they would hit other rocks and they would just shatter but the break would always beclean. So what then differentiates for example our skin from an elephant's skin? Because clearly we know that that would be very different. They would feel very very different. But they're both still kind of skin. So this is kind of where we're gonna start things. Let's say let's try athought experiment (假想实验). Let's say for example you have a piece of chalk and you break this piece of chalk into two. You still have two pieces of chalk now just smaller. So then youtake that chalk and you break it again you break it again and again until it'sso small that you can't quite break it.Your fingers are too big. So then you get a powerfulmicroscope (显微镜)and you get littletweezers (镊子)you continue to do it break it apart again and again and again. Is it still gonna be chalk? I mean you might think well I know that an eraser for a chalk board when Iclap (拍打)it clap two of them together I getchalk dust (粉笔灰尘). It seems to have the same white color the chalk does. Or you know if you were using colored chalk it would be red or green or whatever color. So then that means that our chalk is still chalk as we break it into smaller and smaller pieces. But is there a limit to this? What if everything was made up of one one thingjust the same thing? Well interestingly enough this was this is a concept that's existed since all the way back to theancient Greeks(古希腊). And what we're just going to do right now is we're going to skip ahead a little bit to about the 1700s when chemists or scientists at the time were finally starting to see that there were certainchemicals (化学品)that they couldn't break down further. And they were calling these chemicals elements. And the idea being that these elements were actually what made up everything else. And at the same time that this was happening there were somescientists who were investigatingstatic electricity (静电). They knew that if theyrubbed (摩擦)two materials together they woulddevelop charge(起电). They would attract each otherorrepel each other (互相排斥). But it wasn't clear how this was happening. Was it an exchange of something? Was there some sort ofdeficit (减损)on one material and asurplus (增加)of something on the other one? What was happening? Interestingly enough all these questions are gonna kind of come together to create a basis for on which we're gonna learn and understand how nuclear physics came to be. And then we'll tieit together with some of the stuff we talked about inquantum (量子力学)last time. And that'll be hopefully very informative. So see you guys next time.

重点词语

ancient Greeks古希腊

bend使弯曲

chalk dust粉笔灰尘

clap拍打

deficit减损

initially乍看

microscope显微镜

rub摩擦

shatter碎裂

stretch延展

surplus增加

tweezers镊子

twist扭曲

重点短语

develop charge起电

repeleach other互相排斥

专业术语

aluminum铝

chemicals化学品

copper铜

quantum量子力学

staticelectricity静电

thought experiment假想实验

纠音小课堂第21课

Aaron老师的发音是不是特别好听!那么,纠音小课堂来啦!听听单词子句该怎么读,保证让大家拥有一口流利的美式英语!!

我们今天的金句为:

There were some scientists who were investigating static electricity. They knew that if they rubbed two materials together they would develop charge.They would attract each other or repel each other.

There were some scientists ∧­who were investigatingstatic electricity.〡Theyknewthat if they rubbedtwomaterials together­∧they would developcharge.〡They wouldattracteach other­∧orrepeleach other.

失去爆破:rubbed two would develop

连读:static electricity that if would attract attract each each other repel each

重读:见黄色高亮

语调:见箭头标注(­)

断句:短暂停顿见∧,稍长停顿见〡

易错单词:scientists staticelectricity

枸橼酸西地那非片使用方法

伟哥有哪些功效?

伟哥真的能延时吗 伟哥能延长多少时间一粒?

进口伟哥多少钱

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