Why Is the Sky Blue?

It is very important for us to understand why the sky above us which we see every day looks blue. Are there some reasons behind this? There must be a very interesting reason behind this phenomenon which we all should know. The colour of the sky is because of the very interesting property of light called Scattering of light.

In this article, we’re going to understand why the colour of the sky is blue.

Important Terms

Let’s take a look at some important terms which we are going to use in this article.

Atmosphere: It is the layer of gases that surrounds the Earth comprised of nitrogen, oxygen, and many other gases. The atmosphere comprises many layers: troposphere, stratosphere, mesosphere and thermosphere.

Scattering: The process by which the incoming rays of light are scattered by tiny particles present in the atmosphere, causing the sky to appear blue.

Wavelength: The distance between two adjacent points of a wave, such as a crest or a trough.

Spectrum: The range of colours produced by the refraction of light by prisms or other objects.

Spectrum of Light

It refers to the range of colours that we see when white light is separated into its component colours. This range of colours comprises Violet, Indigo, Blue, Grey, Yellow, Orange and Red. Each colour has different wavelengths of light. The color with the largest wavelength is Red and the color with the smallest wavelength is Violet. The term “VIBGYOR” is used to remember the range of colours where V stands for Violet, I stands for Indigo, B stands for Blue, G stands for Grey, Y stands for Yellow, O stands for Orange, and R stands for Red. 

The image added below shows the white light passing through the glass prism and breaking the white light into the spectrum of white light.

Learn more about, Dispersion of Light by Prism

Scattering of Light

When light is passed through a medium such as water, air, etc. and it gets redirected in all possible directions resulting in changing the direction of light rays. This phenomenon is called the Scattering of Light. An example of the scattering of light is the blue colour of the sky. Scattering of the light phenomenon also occurs in our everyday life such as when light is passed through a foggy window or mirror or water, it gets scattered.

Why Is Sky Blue?

The colour of the sky is blue due to a phenomenon called Scattering. When the rays of sunlight coming from the sun enters into the atmosphere of the Earth, then the tiny particles of dust, gases, etc. which are always present in the air, scattered the sunlight in all possible directions. The human eye finds the scattered light in blue colour as it gets scattered the most because of its smaller wavelength, That is why, we see the sky in blue colour.

The color of the sky is blue and the image added below shows the blue sky.

When the sunlight enters the Earth’s atmosphere, it comprises a number of colours ranging from Violet to Red. After interacting with the particles present in the atmosphere of the earth, scattering occurs and the Blue colour has a shorter wavelength due to which it scattered more than other colours present in the incoming sunlight. Due to this scattering, the blue colour gets scattered in all possible directions which makes it visible to our eyes. 

Why Is Sunset Red?

Longer-wavelength colours like red and orange are not scattered as much as blue light. During sunrise and sunset, when the sun is low on the horizon, the sky appears to be red or orange. At this time, the light has to travel through more of the atmosphere before reaching our eyes, which causes the blue light to scatter more, leaving only the red and orange colours visible. 

There are a lot of tiny particles of dust present in the air which plays an important role in the scattering of sunlight. So, the sun appears red during sunset due to extreme scattering of the blue colour due to which only reddish colour is visible to eyes during the sunset in the evening. 

The color of the sky during early morning and evening is red as shown in the image below.

Thus, we can say the colour of the sky is a result of the phenomenon of Rayleigh Scattering. The shorter-wavelength blue light is scattered more than other colours, making it visible to our eyes and giving the sky its iconic blue hue. However, the colour of the sky can vary depending on weather conditions, time of day

Read More,

• Reflection of Light
• Refraction of Light

Frequently Asked Questions

Q1: What makes the sky blue?

Answer:

Sky seems to be blue due to the phenomenon of Scattering. When sunlight enters the Earth’s atmosphere, it is scattered in all directions by gases and other dust particles present in the atmosphere. This scattered light appears blue to human eyes.

Q2: Can pollution change the colour of the sky?

Answer:

Yes, pollution can change the color of the sky. when large amount of particles present in the atmosphere, it scatter the light more and change color.

Q3: Can the colour of the sky be different on other planets?

Answer:

Yes, the color of the sky on other planets can vary depending on their atmosphere’s composition and the interaction of light and atmospheric particles.

Q4: What is the scientific phenomenon explaining the scattering of light in the atmosphere?

Answer :

Rayleigh Scattering is responsible for explaining the scattering of light in the atmosphere.

Q5: What is difference between reflection and scattering of light?

Answer:

Reflection is the bouncing of light off a surface after striking it, while scattering is the redirection of light in all directions when a light ray enters the atmosphere the small particle in the atmosphere absorb the light and radiate them in all directions this is called scattering of light.