跟读练习: What is the universe made of? - Dennis Wildfogel - 通过YouTube学习英语口语
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All the material objects around you are composed of submicroscopic units we call molecules.
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38 句
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All the material objects around you are composed of submicroscopic units we call molecules.
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And molecules in turn are composed of individual atoms.
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Molecules frequently break apart and then form new molecules.
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On the other hand, virtually all the atoms you come in to contact with through the course of your life, the ones in the ground beneath you, the air you breath, the food you eat, those that make up every living thing, including you, have existed for billions of years and were created in places very unlike our planet.
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How those atoms came about is what I want to share with you.
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It all started 14 billion years ago with an event we call The Big Bang, which resulted in a universe consisting of gas alone.
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There were no stars and no planets.
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The gas was made up only of atoms belonging to the simplest elements.
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It was about 75 percent hydrogen and almost all the rest was helium.
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No elements like carbon, oxygen or nitrogen existed.
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No iron, silver or gold.
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In some places, the density of this gas was slightly higher than in others.
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Due to gravity, those places attracted even more gas, which further strengthened the pull of gravity, which then drew more gas in, and so on.
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Eventually, large dense gas balls formed, shrinking under their own gravity and consequently heating up on the inside.
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At some point, the core of such a ball gets hot enough that nuclear fusion occurs.
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Hydrogen atoms smash together to form helium, accompanied by a great release of energy, strong enough to counteract the shrinking force of the gravity.
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When the energy pushing out from the fusion reactions matches the gravity pulling all the gas inwards, an equilibrium occurs.
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From this a star is born.
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Over its lifetime, the fusion reactions in the core of a massive star will produce not only helium, but also carbon, oxygen, nitrogen and all the other elements in the periodic table up to iron.
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But eventually, the core's fuel runs out, leaving it to collapse completely.
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That causes an unbelievably powerful explosion we call a supernova.
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Now there are two things to note about how supernovas create elements.
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First, this explosion releases so much energy that fusion goes wild forming elements with atoms even heavier than iron like silver, gold and uranium.
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Second, all the elements that had been accumulating in the core of the star, like carbon, oxygen, nitrogen, iron, as well as all of those formed in the supernova explosion, are ejected in to interstellar space where they mix with the gas that's already there.
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History then repeats itself.
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Gas clouds, now containing many elements besides the original hydrogen and helium, have higher density areas that attract more matter, and so on.
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As before, new stars result.
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Our sun was born this way about 5 billion years ago.
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That means that the gas it arose from had itself been enriched with many elements from supernova explosions since the universe began.
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So that's how the sun wound up with all the elements.
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It's still mostly hydrogen at 71 percent, with most of the rest being helium at 27 percent.
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But bear in mind that while the first stars were made up of hydrogen and helium alone, the remaining elements in the periodic table make up two percent of the sun.
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And what about Earth?
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Planets form as an incidental process to star formation out of the same gas cloud as the star itself.
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Small planets like ours don't have enough gravity to hold on to much hydrogen or helium gas since both of those are very light.
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So, even though carbon, nitrogen, oxygen and so on made up only two percent of the gas cloud from which Earth was formed, these heavier elements form the bulk of our planet and everything on it.
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Think about this: with the exception of hydrogen and some helium, the ground you walk on, the air you breath, you, everything is made of atoms that were created inside stars.
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When scientists first worked this out over the first half of the 20th Century, the famous astronomer Harlow Shapley commented, "We are brothers of the boulders, cousins of the clouds."
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Shadowing English
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为什么要通过这个视频练习口语？
通过观看看YouTube学英语的视频，学习者可以在丰富的科学话题环境中锻炼他们的英语口语能力。本视频讲述了宇宙的构成，涉及分子、原子和星星等概念。在这样的语境中练习口语，不仅能够提升对复杂英语表达的理解，还能帮助学习者掌握如何在谈论科学时使用准确的语言和术语。通过模仿视频中的发音和语调，学习者可以提高他们的提高英语发音能力，同时增强他们的自信心。
语法和表达的语境分析
在视频中，讲者使用了一些重要的表达方式和语法结构，例如：
- 被动语态：例如“被称为”，这种结构通常用于介绍新的概念或术语。
- 时态的运用：讲者使用过去时描述了宇宙的形成过程，帮助学习者理解如何在叙述历史事件时选择合适的时态。
- 条件句：很多科学解释中使用了条件句，例如“如果……那么……”，此类结构在讨论假设或科学理论时非常常见。
通过这些表达，学习者可以更好地理解如何在英语口语中形成逻辑和连贯的论述，同时使用shadow speak的方法进行有效的模仿练习。
常见发音陷阱
视频中的某些单词和短语可能会对学习者造成发音上的挑战。例如：
- supernova（超新星）：这个词对非母语者来说可能较为陌生，发音时注意重音的位置和元音的发音。
- elements（元素）：这个词的发音要特别注意，尤其是中间的音节。
- hydrogen（氢）：在快速说话时容易发生误读，确保每个音节都要清晰发出。
练习这些单词及其在句子中的发音，能够帮助学习者避免常见的发音错误，并提升他们在实际交流中的流畅度，同时提高自我表达的能力。
什么是跟读法？
跟读法 (Shadowing) 是一种有科学依据的语言学习技巧，最初开发用于专业口译员的培训，并由多语言者Alexander Arguelles博士普及。这个方法简单而强大：您在听英语母语原声的同时立即大声重复——就像是一个延迟1-2秒紧跟说话者的影子。与被动听力或语法练习不同，跟读法强迫您的大脑和口腔肌肉同时处理并模仿真实的讲话模式。研究表明它能显着提高发音准确性，语调，节奏，连读，听力理解和口语流利度——使其成为雅思口语备考和真实英语交流最有效的方法之一。