IELTS Listening: why is the sky blue?

Watch the short presentation and fill the gaps in the sentences below.

Here's a recording in case you can't see the video:

Click here to listen

Fill each gap with ONE word only.

1. The distance between each _____ in a wave of light is called the wavelength.
2. When all the different wavelengths travel together, light appears _____.
3. _____ light waves have a longer wavelength than blue.
4. The atmosphere is made up of _____ which change the way light behaves.
5. Shorter blue light waves _____ with particles more often and spread throughout the atmosphere, filling the sky.
6. Other colours pass through and appear _____-white when they mix together.

Comments

[Marina]

Thank you for this excellent exercise!

1. bump
2. white
3. red
4. perticles
5. interact
6. yellowish

[Hung]

1: color
2: white
3. red
4. particles
5. often
6. yellow

[Lien Nguyen]

1. Bump
2. White
3. Red
4. Particles
5. Interact
6. Yellowish

[Hoangluyen]

1. plop
2. White
3. red
4. particles
5. interact
6. yellow

[Hitomi]

1. bump
2. white
3. red
4. particles
5. interact
6. yellowish

[Hong Nguyen]

1. bump
2. white
3. red
4. particles
5. interact
6. yellowish

[Madina]

Hello sir. I took the exam last week there was a question about a date of birth of a person who wanted to apply for a job. She said that she was born on 16 October 1989, but the task requirement was to write only two words and/or two numbers.What should be the correct answer for this question?

[Amura]

I think that you need to write 16th October 1989, so your answer is correct. There are two number is 16th and 1989. You can write one word or two words.

[sidra]

Bump
White (to our eyes)
Red
Particles
Interact
Yellowish
@Madina ,the answer is 16 of your question, as question required for date of birth not year or month . Thanks

[H. A. Kader]

1. bump
2. white
3. red
4. particles
5. interact
6. yellowish

Why is sky blue?

Well, first we need to understand a little bit about how light works? Light travels from the sun up and down like a wave similar to the waves you see in the ocean. Some waves are close together and others are further apart. The distance between each (1) bump in a wave is called wavelength and when all of the different wavelengths travel together, light appears (2) white to our eyes. But if you break up sunlight so that the waves are separated, you will see individual colours. In fact, every colours has its unique wavelength.

Bluish colour have a short wavelength and move up and down often than a colour like (3) red which has a longer wavelength. So, if light from the sun contains all of these different colours, why does the sky appear blue?

Well, it also has to with the way these waves interact with the atmosphere. If there is nothing between the sun and our eyes, the sun would look like a white circle in a black sky. But the atmosphere gets in the way and changes the way light behaves. While the atmosphere may seem like a large empty space, it is actually made up of a whole bunch of tiny (4) particles like air molecules, water, and dust. Light waves are tiny too, so when they finally reach the atmosphere they have a hard time dodging the small particles in the sky. The shorter wavelength of light, like blue and violet, move up and down so much they tend to (5) interact with the particles more often than other colours.

These colours get bunched around so much they spread through the atmosphere and fill the sky. Even though purple light is also scattering out across the sky, our eyes are more sensitive to blue light, and so the sky appears more of a bluish colour. Red, yellow, and green coloured lightwaves bounce around too, but not as much and more of this light passes through. When these colours are mixed together, they appear a (6) yellowish-white, which is why the sun looks somewhat yellow to our eyes. So, now you know that when you look at a blue sky you are actually looking at a portion of sunlight that has been broken up and scattered by billions of tiny particles.

[Nhat-Nguyen Tran]

Great work Kader!

[Amal]

1- bump
2- White
3- Red
4- particles
5- interact
6- yellowish

[H. A. Kader]

Dear Simon,

I find the multiple choice and matching questions more difficult and cannot complete reading withing the time given. So, how can we manage the timing for reading the question plus multiple options?

[ding]

1. bump 2. white 3. Red 4. Particles 5. Interacts 6. Yellowish

[Lala]

1. bump
2.white
3. red
4.particles
5.interaction
6.yellowish

[Haseeb]

1. -
2. White
3. Red
4. Particles
5. Interact
6. Yellowish

[Simon]

CORRECT ANSWERS FROM SIMON:

1. bump
2. white
3. red
4. particles
5. interact
6. yellowish

Thanks for the transcription H.A. Kader. I'll check it for next week.

[H. A. Kader]

Its an honour for me getting a thank from you, Simon. Many thanks for your thank.

Waiting for the review.

[Ertugrul]

I have really trouble part of listening section on ıelts.. I can't find correct answers for this kind of questions in the first time and ı don't know how can I overcome to this matter... Thank you in advince for all your comments.

[nina]

Hi Simon,

I saw only afew MAP questions (istening) in your blog! Can you please give some more advice and questions about MAP. It is really my weakness and most of the times, I get easily lost.

[Reza1984]

Hi Simon,

I am writing to you with the hope of getting a response. I know you are so busy. But please please help me. I am so disappointed and about to give up. I had the test so many times and always stuck in 7 or 7.5 in Listening. Although I do listen actively everyday and do transcription as you suggest. I am not still getting my target which is 8. I figured out that my 2 biggest problems are 1) lack of time reading the multiple choice questions and 2) comprehension whenever the answers are so close. I have even got depression. That is too bad that the whole of my future life depends on getting an IELTS listening 8!!! I need it for immigration!

[Z. Li]

1.bump
2.white
3.red
4.particles
5.interact
6.yellowish

[Oğuz]

1. Bump
2. White
3.Red
4.Dust (was supposed to be particles)
5.Interact
6.Yellowish

[kid]

Hello, I'm a beginer in ielts, and I don't know the way to learn ielts, any one can help me?
Those excersise are too hard for me

[nina]

Need help from you guys:

In Cambridge 7, Test4 Listening, the answer to question 7 (which is a short answer type of question), I wrote "seafoods" instead of "seafood"? Do I lose point for such mistake? although the recording says "seafood", when I google it, plural form "seafoods" is gramatically correct. I am confused if I should get a point for this question or not?
please help.

[viva]

thanks.

[Virpal kaur]

My exam will on 10 september (Gt exam) please suggest any impotannt topics

[PK]

1. Bump
2. White
3. red
3. Tiny Particles
4. Interact
5. Yellowish

[RH]

1- bump
2- individual colors
3- red
4- tiny particles
5- interact
6- yellowish

[Firdavs]

Bump
White
Red
Particles
Move up
Yellow

[NIKI]

bampe?? bump
white
red
particle
act?? interact
yellowish