Sunset is red in color

Because sunsets are romantic?

Here’s the reason,why SUNSET IS RED?

It is because of scattering of the light in the atmosphere. The atmosphere is basically composed of tiny oxygen and nitrogen particles. Usually, when sunlight comprising of 7 colors passes through the atmosphere.It comes in contact with the oxygen and nitrogen particles.These particles scatter violet and the blue light More as compared to the red. Orange light and other colored lights. So the Sunset appears to be in red in color.

However, during sunset. The sunlight should go through a long distance in the earth’s atmosphere. Causing it to pass through more particle. AS a result, most of the violet and blue light Get scattered before they reach our eyes. This the reason for the less scattered light like orange or red reaches our naked eyes.

Why the sky is blue and clouds aren’t ?

However the physics behind them is not difficult at all! There are two things that play an important role In giving a colour to the sky. One is the atmosphere of the Earth And the other is the sunlight of course.
So we need to know a more about these two first. The white light coming from the sun is a mixture Of seven primary colours , And each coloured light has a corresponding frequency And wavelength associated with it. The violet coloured light has the shortest wavelength of all While the red one has the largest wavelength! And what forms the Earth’s atmosphere?


The Earth’s atmosphere is mainly composed of gases, Dust particles, water droplets and water vapour. Among the gases,
Nitrogen is present in abundant quantity, At around 78%. It is followed by Oxygen which is approximately 21% And the remaining is filled with the likes of Argon, Carbon dioxide and other gases. First let’s see what happens when the sunlight falls On these air molecules. When sunlight strikes these molecules, It gets scattered.

Scattering is a process In which the light is absorbed by the atoms and are re-emitted back in various directions. However not all the light is scattered equally!

sky is blue

The amount of light that will be scattered Is given by the Rayleigh law of scattering . It says that the amount of scattered light Or the intensity of the scattered light Is inversely proportional To the fourth power of the wavelength of a wave. ‘I’ is inversely proportional to ‘lambda to the fourth power’! If the value of lambda increases, then the intensity will be lower. If its value decreases, Then the intensity of scattering will be more! Lesser the wavelength, more will be the scattering!


The sun emits more blue and light-bluish light Compared to the violet light! Hence more blue light is scattered by the air molecules Resulting in the blue color of the sky. And another reason why we cannot see violet light Is because our eyes are more sensitive to blue light Than to violet light. So this was about how the gases present In the atmosphere scatter light! Do dust particles and water droplets also scatter light?Yes they do!
They scatter light as well.

However their size is comparatively Much bigger than the size of the light waves. And hence they scatter all the colours of light in equal amounts! So the white light which is entering the cloud or the dust particles, Emerges out as white light again!

Conclusion : Mostly the bluish light enters our eyes, hence the making the sky to usually appear blue.And it gives our answer to why sky is blue? and why sunset is red?

Categories: Education


Comments are accepted here.