Shadowing Practice: Molecules, crystals, and diatomic elements | Middle school chemistry | Khan Academy - Learn English Speaking with Video
Elige un modo de práctica
Cada modo abre una sala de práctica a pantalla completa.
124 oraciones
Si las oraciones son demasiado cortas o largas, haz clic en Editar para ajustarlas.
1
If you zoom into water,
2
you will find a molecule of water,
3
where you have one oxygen atom attached to two hydrogen atoms.
4
You will find trillions and trillions of them.
5
Similarly, if you were to zoom into methane,
6
which we also call natural gas,
7
you will now find molecules of methane,
8
which happens to be one carbon atom attached to four hydrogen atoms.
9
Again, you will find trillions and trillions of them.
10
So the big question now is,
11
what would you get if you were to zoom into table salt, which is NaCl?
12
Well, our guess could be we'll find molecules of NaCl,
13
where one Na is attached to one Cl.
14
Trillions and trillions of them, right?
15
Wrong.
16
That's not what we'd get.
17
We'll get something completely different. But what?
18
Well, let's find out.
19
So what will we find if we were to zoom into NaCl?
20
We'll get something like this,
21
where you'll find trillions of Na's and trillions of Cl all connected to each other.
22
We call this a crystal of sodium chloride, crystal of NaCl.
23
You probably heard of this word crystal,
24
it means we have an orderly repeating pattern.
25
This looks very different, right?
26
So let's compare it with what we saw earlier.
27
If we were to go back to the molecules of water,
28
what we find is that an individual oxygen is connected to two other hydrogen atoms.
29
And that connection is due to a force of attraction,
30
which we call a chemical bond.
31
The same thing is happening over here.
32
There's a chemical bond because of which a carbon atom is attached to four hydrogen atoms,
33
right but
34
when it comes to a crystal of NaCl look we don't
35
have individual molecules like with what we see over here we don't find them instead we find trillions
36
and trillions of Na's connected to trillions and trillions of Cl in
37
that chemical bond so there are no individual molecules you only have a crystal
38
but wait a second wait a second wait a second again if we go back to molecule of water.
39
The reason why we call it H2O is
40
because you have two hydrogen atoms connected to one oxygen atom to form a single unit molecule, right?
41
Same is the case over here.
42
It's because you have one carbon attached to four hydrogens.
43
That's why we say the,
44
you know, this is CH4.
45
But what about over here?
46
Why do we call it NaCl?
47
I mean, if you don't have individual molecules,
48
what does it mean to say NaCl?
49
Well, what it means is that if you were to take a chunk of this crystal,
50
then you will find equal amounts of Na and Cl.
51
In other words, you will have them in the ratio 1 is to 1.
52
For every 1 Na, you will find 1 Cl.
53
That is what that means over here.
54
It doesn't mean that you'll find a molecule of NaCl where 1 Na is attached to 1 Cl.
55
No, no, no. You find a crystal,
56
but the ratio of NaNCl is 1 is to 1.
57
That's what it means over here.
58
And we can take another example of the salt.
59
There are other salts as well.
60
So for example, if you take potassium oxide,
61
it also happens to be a salt.
62
It is K2O, where K is potassium, O is oxygen, okay?
63
But what does it mean to say K2O?
64
Does it mean that there are molecules of K2O?
65
No, this is again a crystal.
66
It's a crystal of potassium oxide.
67
But what does it mean for us to say K2O?
68
Well, what it means now is that if you were to take a chunk of this crystal,
69
you will find that there are twice as many potassium as oxygen.
70
You'll have two potassium atoms for every oxygen atoms.
71
That's what it means to say it is K2O.
72
So putting it all together,
73
what we have so far is that we can have two kinds of compounds.
74
We have compounds that are made of individual molecules and we have compounds which are made of crystals.
75
Now, of course, these are just two general categories of compounds,
76
but there are more advanced forms of compounds as well.
77
We'll not worry too much about them.
78
But anyways, the compounds that are made of molecules are called molecular compounds
79
and the ones that are made of crystals are called crystalline compounds.
80
So look, not all compounds are made of molecules.
81
That's the important thing.
82
They can also be crystalline.
83
They can also be made of crystals.
84
But here's an interesting question.
85
Not all compounds are molecules, right?
86
But what about the other way around?
87
Are all molecules compounds?
88
Well, let's see.
89
Let's take an example.
90
What if we were to zoom into oxygen?
91
Well, we'll find that two atoms of oxygen are combined together to form O2,
92
which is a molecule of oxygen.
93
And of course, we'll find trillions and trillions of them.
94
But the big question is, is this a compound?
95
The answer is no, it's not a compound.
96
Because remember, compounds are chemical combination of two or more different elements.
97
Here, there's a chemical combination of the same element.
98
Oxygen and oxygen is getting combined.
99
So it's a molecule, but it is not a compound.
100
In fact, we call this as diatomic element.
101
Di because there are two.
102
And there are other examples of diatomic elements.
103
Nitrogen, fluorine, chlorine, and many more.
104
Well, of course, one thing to remember is
105
that these elements are usually diatomic when they're alone like when you have oxygen gas or chlorine gas.
106
But of course, when they do form a compound, they can split apart.
107
Again, go back to molecule of water.
108
You can have one oxygen atom combined to two hydrogen atoms.
109
Anyways, if you put it all together,
110
we have elements which are the fundamental building blocks of matter.
111
Some elements are made of individual atoms.
112
We usually call them monoatomic,
113
mono for single individual, like gold or mercury.
114
And other elements can be formed as diatomic,
115
like molecules of nitrogen or oxygen.
116
And when two or more different elements chemically combine together, we get compounds.
117
We can have molecular compounds where you find individual molecules,
118
or we can have crystalline compounds when there are no molecules at all.
119
And finally, we categorize this all under what we call pure substances,
120
because they're made of purely the same stuff.
121
For example, water is purely made of water molecules.
122
sodium chloride is purely made of NaCl
123
and oxygen for example is purely made of oxygen molecules so
124
because they're all made of purely the same stuff these are all pure substances
Descargar app
Todo lo que necesitas para hablar con fluidez
Pronunciación con IAEvalúa cada oración
Práctica de IPADomina cada sonido
VocabularioConstruye tu banco de palabras
Juego de vocabularioAprende mientras juegas
Mismo canal
B16
LearnStorm Growth Mindset: How to write a SMART goal
American AccentBusiness EnglishHigh School StudentsUniversity Students
C115
Introduction to high school physics | Khan Academy
American AccentHigh School StudentsUniversity Students
B19
States of matter | Middle school chemistry | Khan Academy
American AccentTOEFL PrepCambridge Exam PrepHigh School Students
B12
Elements | Middle school chemistry | Khan Academy
American AccentHigh School StudentsUniversity Students
B12
Newton's second law | Middle school physics | Khan Academy
American AccentHigh School StudentsUniversity Students
C13
Derivative as slope of a tangent line | Taking derivatives | Differential Calculus | Khan Academy
American AccentCambridge Exam PrepUniversity StudentsWorking Adults
B13
Atoms | Middle school chemistry | Khan Academy
American AccentTOEFL PrepCambridge Exam PrepHigh School Students
C13
Pixar in a Box | Welcome to Pixar in a Box | Khan Academy
American AccentHigh School StudentsUniversity Students
C14
Proportional reasoning with motion | AP Physics | Khan Academy
American AccentBusiness EnglishUniversity StudentsWorking Adults
C12
Biology overview
American AccentUniversity Students
C12
Newton, Leibniz, and Usain Bolt | Derivatives introduction | AP Calculus AB | Khan Academy
American AccentCambridge Exam PrepUniversity StudentsWorking Adults
B12
Introduction to interest | Interest and debt | Finance & Capital Markets | Khan Academy
American AccentBusiness EnglishUniversity StudentsWorking Adults
B2How to rationalize a denominator | Exponent expressions and equations | Algebra I | Khan Academy
Daily ConversationHigh School Students
FOR YOU
Recomendar Video
B11
45 oraciones
Simplifying Fractions
American AccentHigh School StudentsUniversity Students
B14
91 oraciones
Why is the sky blue?
American AccentTeensDaily ConversationHigh School Students
C15
24 oraciones
This structure feels impossible to move
Daily ConversationUniversity StudentsWorking Adults
C12
171 oraciones
The Most Important Picture in the History of Science
American AccentIELTS PrepTOEFL PrepUniversity Students
C11
43 oraciones
What is an Organization? - the Nature of Organizations
Business EnglishUniversity StudentsWorking Adults
C11
14 oraciones
How Distillation Columns Separate Chemicals
Daily ConversationUniversity Students
B25
28 oraciones
How We Use Water
Daily ConversationHigh School StudentsUniversity Students
B24
122 oraciones
How Chemistry Shapes Great Films (And Makes Them Unforgettable)
American AccentDaily ConversationUniversity StudentsWorking Adults
C137
90 oraciones
How do bees make honey?
American AccentIELTS PrepTOEFL PrepUniversity Students
C13
131 oraciones
Unit Conversion & Significant Figures: Crash Course Chemistry #2
Daily ConversationHigh School StudentsUniversity Students
Vocabulario y notas de pronunciación para esta lección
Esta lección de conversación de nivel C1 se basa en el vídeo “Molecules, crystals, and diatomic elements”. Las palabras que más se repiten: molecule, compound, oxygen, atom, trillions. Este vídeo tiene 124 frases y 1117 palabras para practicar shadowing. La parte hablada dura 6:04. El hablante habla rápido, unas 184 palabras por minuto, así que espera sonidos enlazados y reducidos. Solo el 79 % de las palabras está entre las 3.000 más comunes del inglés, por lo que el vocabulario es exigente.
Vocabulario clave de este vídeo
Las 15 palabras más avanzadas del vídeo, con su pronunciación y significado:
| Palabra | Pronunciación | Significado |
|---|---|---|
| molecule sustantivo | /ˈmɑ.lɪ.kjul/ | molécula |
| atom sustantivo | /ˈætəm/ | átomo |
| hydrogen sustantivo | /ˈhaɪdɹəd͡ʒ(ə)n/ | hidrógeno |
| attach verbo | /əˈtæt͡ʃ/ | adjuntar, atachar |
| potassium sustantivo | /pəˈtæsiəm/ | potasio |
| zoom verbo | /zuːm/ | zumbar |
| crystalline adjetivo | /ˈkɹɪs.tə.lɪn/ | cristalino |
| chloride sustantivo | /ˈklɔɹˌaɪd/ | cloruro |
| chlorine sustantivo | /ˈklɔɹin/ | cloro |
| methane sustantivo | /ˈmiːθeɪn/ | metano |
| chunk sustantivo | /t͡ʃʌŋk/ | trozo, pedazo |
| oxide sustantivo | /ˈɑksaɪd/ | óxido |
| nitrogen sustantivo | /ˈnaɪ.tɹə.d͡ʒən/ | nitrógeno |
| sodium sustantivo | /ˈsəʊ.di.əm/ | sodio |
| categorize verbo | /ˈkætɪɡəˌɹaɪz/ | categorizar |
Phrasal verbs que vas a escuchar
| Palabra | Significado |
|---|---|
| find out verbo | averiguar, anoticiarse |
Frases que vale la pena repetir
Frases cortas y completas del vídeo que puedes reutilizar en la conversación diaria:
- That's not what we'd get.
- We'll get something completely different.
- You'll have two potassium atoms for every oxygen atoms.
- We'll not worry too much about them.
- What if we were to zoom into oxygen?
Gramática en este vídeo
Las estructuras que más usa el hablante, con las palabras exactas del vídeo:
| Estructura | En el vídeo |
|---|---|
| Voz pasiva be + participio pasado — importa lo que ocurre, no quién lo hace | is attached · is connected · are made |
| Oraciones de relativo who / which + oración — información extra sobre una persona o cosa | salt, which is · compounds which are · elements which are |
Pronunciación a tener en cuenta
El hablante usa 17 contracciones y formas reducidas, como we'll, don't, they're. Dilas en su forma corta, tal como las oyes.
- Palabras largas — cuida el acento: categorize /ˈkætɪɡəˌɹaɪz/, mononucleosis /ˌmɑnoʊnukliˈoʊsɪs/
Sonidos difíciles para hispanohablantes:
- /z/ — sonora, no /s/: zoom /zuːm/, anyways /ˈɛn.iˌweɪz/, categorize /ˈkætɪɡəˌɹaɪz/
- /dʒ/ — no es la “y” ni la “ch”: hydrogen /ˈhaɪdɹəd͡ʒ(ə)n/, nitrogen /ˈnaɪ.tɹə.d͡ʒən/
Cómo practicar con este vídeo
- Escucha el vídeo entero una vez sin hablar y anota las palabras que no conoces.
- Empieza a velocidad 0,75×, haz shadowing frase por frase y vuelve a la velocidad normal cuando te resulte fácil.
- Grábate y compara con el original, prestando atención a palabras como molecule, atom, hydrogen.
¿Qué es la Técnica de Shadowing?
Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.