Pratique du Shadowing: Why is the sky blue? - Apprendre l'anglais à l'oral avec la vidéo
Création de la leçon...
1
Hi it's Doug.
2
I've got a plastic sandwich bag and I was noticing how
3
if you look through one plastic sandwich bag it's clear but
4
if you get a whole bunch of them check this out
5
now it's not clear it looks kind of blue you see
6
that the reason I have these plastic sandwich bags with me is
7
because I heard there's an interesting question this week from someone named Celine Let's give her a call now.
8
Hi, Doug.
9
Hi, Celine.
10
Good to see you.
11
Our class has a question for you.
12
Why is the sky blue?
13
That's a great question.
14
Before I say anything, I want you to stop and think about it.
15
What do you think?
16
Could you come up with any idea for why you think the sky is blue?
17
Now would be a good time to pause the video so that you can think and discuss this with someone near you.
18
Okay, you ready?
19
There are a lot of different ideas you could have come up with.
20
I can't guess all of the ideas you might have had, but I'll bet at least one of you thought, maybe the sky is blue because our oceans are blue.
21
Like, maybe the sky reflects the color of our oceans.
22
That's a really interesting idea.
23
There's actually a way to figure out if that's the reason.
24
Think about it.
25
If the color of the sky had to do with the color of Earth's surface, then if you were in the middle of a continent, surrounded by thousands of miles of land,
26
like this, then the sky shouldn't look blue at all, right?
27
It should actually look green, reflecting the color of all the land.
28
But that's not the case.
29
Even people who live in the middle of a whole bunch of land still see blue sky.
30
Why is the sky blue then?
31
This is a hard question to solve.
32
Scientists themselves didn't know for a long time.
33
Here's an interesting clue I can point out though.
34
We've sent spacecraft up to the moon and to other planets.
35
And it turns out the sky in those places isn't blue.
36
Have a look at the sky as seen from the moon.
37
Whoa, it's a black sky.
38
Okay, now let's check out what the sky looks like from Mars.
39
You ready?
40
Here it is.
41
Weird, it's kind of a yellowish sky.
42
So the Moon's sky and Mars' sky are somehow different from Earth's sky.
43
What's going on here?
44
Well, keep in mind, our own sky is made out of air.
45
It turns out the Moon has no air at all, so the sky just looks like outer space, even when you're on the surface of the Moon.
46
Now Mars' sky has air, but it's a different kind of air than what's found on Earth.
47
It's mostly made of a gas called carbon dioxide.
48
So the blue color of Earth's sky, this is a view from space, it has something to do with the kind of air that Earth has.
49
Our air is made of two gases.
50
It's got some oxygen.
51
That's the part of air that our bodies need to breathe in.
52
And Earth's air has a whole bunch of another gas, too, called nitrogen.
53
When the sunlight shines on all that oxygen and nitrogen, it looks blue to our eyes.
54
And the reason Mars' sky looks yellow is because of the gas that its sky is made of.
55
When sunlight shines on carbon dioxide, it looks yellow.
56
Now, I have to point something out.
57
This is not the full story.
58
There's more to this question.
59
It's complicated.
60
The reason that our planet's air looks blue also has something to do with how light works.
61
Look around you.
62
You're surrounded by Earth's air.
63
It's the same stuff that's in our sky.
64
But it doesn't look blue, does it?
65
No, it's clear.
66
You see, it matters how much air you're looking at.
67
When you look up at the sky you're looking at a
68
lot more air than just the air in the room around you.
69
Sometimes when you have a lot of something, like this water in a swimming pool, it can look different than when you just have a little bit of something, like this water in a glass of water.
70
It's also kind of like those plastic sandwich bags I was playing with earlier.
71
Just one of them looks clearer, but when you have a whole bunch of them the color looks different,
72
doesn't it it's interesting here's another thing to notice our sky
73
isn't always blue is it at the time around sunrise
74
or sunset you can see lots of different colors especially reddish orange color
75
all of this is something we can explore in a future episode
76
but as a first step toward understanding why our sky is blue you can just notice
77
that our sky is blue because of the type of air we have in our sky.
78
We can see for ourselves by comparing the color of our
79
sky with the color of the sky on other planets and the moon.
80
The way that light works, when you have a whole bunch of our type of air, it looks blue to our eyes.
81
Thanks, Selene, for asking that question.
82
Now, for the next episode, I reached into my question jar and found three questions submitted to me that I'm thinking about answering.
83
When this video is done playing, you'll get to vote on one.
84
you can choose from why do people have different eye colors
85
or if the earth is round why does it look flat
86
or how did alligators get their name so submit your vote
87
when the video is over I want to hear from all
88
of you watching now just like a lot of you are
89
taking a summer break I'm gonna take a break as well
90
but I'll be back in September remember there are mysteries all around you.
91
Have fun and stay curious.
📺 Même chaîne
B11
How can you tell if a mushroom is poisonous?
American Accent, en-USTeens+3
B110
Why do we celebrate April Fool's Day?
American Accent, en-USKids+2
B11
Why do snakes shed their skin?
American Accent, en-USKids+2
A24
How is butter made?
American Accent, en-USKids+2
B17
Are vampires real?
American Accent, en-USTeens+3
B11
Do sharks really want to eat people?
American Accent, en-USTeens+3
C132
How do bees make honey?
American Accent, en-USIELTS Prep+3
B14
Are killer whales really dangerous?
American Accent, en-USTeens+3
B1How is glass made?
American Accent, en-USHigh School Students+1
✨ Vidéo recommandée
B11
21 phrases
Unit 9.The blue sky
High School StudentsUniversity Students+1
B11
30 phrases
AEE - Did You See It or Watch It?
American Accent, en-USTeens+3
B283 phrases
Why Is Blue So Rare In Nature?
American Accent, en-USUniversity Students+1
B12
18 phrases
White sands come from fish?! Beach sands have a story behind them?
TeensHigh School Students+2
A22
19 phrases
Down to Earth: Crash Course Kids #4.2
KidsTeens+2
A24
60 phrases
Defining a Problem: Crash Course Kids #18.1
KidsTeens+2
B21
140 phrases
Mars Used to Be Blue... Then Something Happened
American Accent, en-USIELTS Prep+3
A21
157 phrases
Space Goofs - Back to school Blues (S2E37) Full Episode in HD
KidsTeens+2
B13
305 phrases
How Language Shapes the Way We Think | English Podcast A2–B1 | Listening Practice
High School StudentsUniversity Students+1
B12
264 phrases
Steven Universe Moments that Changed My Life
TeensHigh School Students+1
À propos de cette leçon
Vous vous entraînez en anglais avec "Why is the sky blue?" en utilisant la technique du Shadowing.
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.