シャドーイング練習: Molecules, crystals, and diatomic elements | Middle school chemistry | Khan Academy - YouTubeで英語スピーキングを学ぶ
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If you zoom into water,
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If you zoom into water,
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you will find a molecule of water,
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where you have one oxygen atom attached to two hydrogen atoms.
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You will find trillions and trillions of them.
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Similarly, if you were to zoom into methane,
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which we also call natural gas,
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you will now find molecules of methane,
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which happens to be one carbon atom attached to four hydrogen atoms.
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Again, you will find trillions and trillions of them.
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So the big question now is,
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what would you get if you were to zoom into table salt, which is NaCl?
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Well, our guess could be we'll find molecules of NaCl,
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where one Na is attached to one Cl.
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Trillions and trillions of them, right?
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Wrong.
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That's not what we'd get.
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We'll get something completely different. But what?
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Well, let's find out.
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So what will we find if we were to zoom into NaCl?
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We'll get something like this,
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where you'll find trillions of Na's and trillions of Cl all connected to each other.
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We call this a crystal of sodium chloride, crystal of NaCl.
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You probably heard of this word crystal,
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it means we have an orderly repeating pattern.
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This looks very different, right?
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So let's compare it with what we saw earlier.
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If we were to go back to the molecules of water,
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what we find is that an individual oxygen is connected to two other hydrogen atoms.
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And that connection is due to a force of attraction,
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which we call a chemical bond.
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The same thing is happening over here.
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There's a chemical bond because of which a carbon atom is attached to four hydrogen atoms,
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right but
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when it comes to a crystal of NaCl look we don't
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have individual molecules like with what we see over here we don't find them instead we find trillions
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and trillions of Na's connected to trillions and trillions of Cl in
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that chemical bond so there are no individual molecules you only have a crystal
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but wait a second wait a second wait a second again if we go back to molecule of water.
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The reason why we call it H2O is
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because you have two hydrogen atoms connected to one oxygen atom to form a single unit molecule, right?
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Same is the case over here.
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It's because you have one carbon attached to four hydrogens.
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That's why we say the,
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you know, this is CH4.
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But what about over here?
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Why do we call it NaCl?
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I mean, if you don't have individual molecules,
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what does it mean to say NaCl?
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Well, what it means is that if you were to take a chunk of this crystal,
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then you will find equal amounts of Na and Cl.
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In other words, you will have them in the ratio 1 is to 1.
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For every 1 Na, you will find 1 Cl.
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That is what that means over here.
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It doesn't mean that you'll find a molecule of NaCl where 1 Na is attached to 1 Cl.
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No, no, no. You find a crystal,
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but the ratio of NaNCl is 1 is to 1.
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That's what it means over here.
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And we can take another example of the salt.
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There are other salts as well.
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So for example, if you take potassium oxide,
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it also happens to be a salt.
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It is K2O, where K is potassium, O is oxygen, okay?
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But what does it mean to say K2O?
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Does it mean that there are molecules of K2O?
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No, this is again a crystal.
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It's a crystal of potassium oxide.
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But what does it mean for us to say K2O?
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Well, what it means now is that if you were to take a chunk of this crystal,
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you will find that there are twice as many potassium as oxygen.
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You'll have two potassium atoms for every oxygen atoms.
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That's what it means to say it is K2O.
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So putting it all together,
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what we have so far is that we can have two kinds of compounds.
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We have compounds that are made of individual molecules and we have compounds which are made of crystals.
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Now, of course, these are just two general categories of compounds,
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but there are more advanced forms of compounds as well.
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We'll not worry too much about them.
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But anyways, the compounds that are made of molecules are called molecular compounds
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and the ones that are made of crystals are called crystalline compounds.
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So look, not all compounds are made of molecules.
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That's the important thing.
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They can also be crystalline.
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They can also be made of crystals.
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But here's an interesting question.
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Not all compounds are molecules, right?
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But what about the other way around?
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Are all molecules compounds?
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Well, let's see.
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Let's take an example.
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What if we were to zoom into oxygen?
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Well, we'll find that two atoms of oxygen are combined together to form O2,
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which is a molecule of oxygen.
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And of course, we'll find trillions and trillions of them.
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But the big question is, is this a compound?
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The answer is no, it's not a compound.
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Because remember, compounds are chemical combination of two or more different elements.
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Here, there's a chemical combination of the same element.
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Oxygen and oxygen is getting combined.
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So it's a molecule, but it is not a compound.
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In fact, we call this as diatomic element.
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Di because there are two.
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And there are other examples of diatomic elements.
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Nitrogen, fluorine, chlorine, and many more.
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Well, of course, one thing to remember is
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that these elements are usually diatomic when they're alone like when you have oxygen gas or chlorine gas.
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But of course, when they do form a compound, they can split apart.
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Again, go back to molecule of water.
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You can have one oxygen atom combined to two hydrogen atoms.
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Anyways, if you put it all together,
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we have elements which are the fundamental building blocks of matter.
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Some elements are made of individual atoms.
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We usually call them monoatomic,
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mono for single individual, like gold or mercury.
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And other elements can be formed as diatomic,
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like molecules of nitrogen or oxygen.
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And when two or more different elements chemically combine together, we get compounds.
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We can have molecular compounds where you find individual molecules,
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or we can have crystalline compounds when there are no molecules at all.
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And finally, we categorize this all under what we call pure substances,
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because they're made of purely the same stuff.
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For example, water is purely made of water molecules.
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sodium chloride is purely made of NaCl
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and oxygen for example is purely made of oxygen molecules so
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because they're all made of purely the same stuff these are all pure substances
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この動画でスピーキングを練習する理由は？
この動画を通じて化学を学びながら、英会話のスキルを向上させることができます。スピーキングの練習は、英語の学習において非常に重要です。特に、化学のような専門用語を含むコンテキストでの練習は、実用的なコミュニケーション能力を高める助けになります。動画内で扱われる「水の分子」や「塩の結晶」といった具体的なテーマを通じて、文脈に応じた語彙や表現を効果的に学ぶことができるでしょう。これは、あなたが英会話で自信を持つための強力な武器になるでしょう。
文法と表現の文脈での分析
- 「connected to」 - この表現は、化学結合を示す際に使われ、何かが他の要素とどのように関わっているかを説明します。
- 「find trillions of」 - この句は数量を強調するのに役立ち、数の大きさを示す際によく利用されます。
- 「there are no individual molecules」 - これは否定文を使って対象を明確にする良い例です。化学的な概念を話す時に、言語的にどう表現するかを学ぶことができます。
これらの文法構造を使って、自分自身の言葉で表現する練習をすることが、実際の英会話に自信を持たせる一助となります。特に、shadowspeaksやshadow speakのテクニックを活用して、リスニングからスピーキングへの移行をスムーズにすることが重要です。
一般的な発音の罠
この動画ではいくつかの発音に注意を払う必要があります。特に「NaCl（エヌエーシーエル）」の発音は、英語話者が正しく理解するためには注意が必要です。また、「hydrogen（ハイドロジェン）」や「oxygen（オキシジェン）」のような言葉も、ネイティブの発音に近づける練習が必要です。shadow speechのテクニックを使用することで、文の流れを練習し、発音を改善することができます。何度も繰り返し練習することで、難しい音やアクセントを克服できるでしょう。
シャドーイングとは？英語上達に効果的な理由
シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。