The sky is blue because the Earth’s atmosphere scatters sunlight in all directions, and blue light is scattered more than other colors because it travels as shorter, smaller waves. Blue is scattered more than other colors because it travels as shorter, smaller waves.
The blueness of the sky is the result of a particular type of scattering called Rayleigh scattering. In the lower atmosphere, tiny oxygen and nitrogen molecules scatter short-wavelength light, such as blue and violet light, to a far greater degree than long-wavelength light, such as red and yellow.
Let’s have a closer look.
One of the most iconic things in nature is a sunny sky with fluffy clouds – thanks to Rayleigh scattering. In this article, we’ll find out what Rayleigh scattering is and how it makes the sky look blue.
So what is Rayleigh scattering?
In short, it’s the scattering of light by particles that are much smaller than the wavelength of light. The sky looks blue because the molecules in the atmosphere scatter short-wavelength light more than they scatter long-wavelength light.
The sky is blue because of Rayleigh scattering. But what is Rayleigh scattering? Rayleigh scattering occurs when light is scattered by particles that are much smaller than the wavelength of light. The molecules in the atmosphere scatter short-wavelength light more than they scatter long-wavelength light. The blue end of the visible spectrum is scattered more than the red end. That’s why the sky looks blue most of the time.
So now we know that the sky is blue because of Rayleigh scattering. But why does this happen? To understand this, we need to know a bit about light.
Light is a type of energy
Light is a type of energy that travels through the air and is used to see things. It is made up of tiny particles called photons. These photons travel through the air and bounce off things, like clouds, to enter our eyes.
Clouds are made up of water droplets, which are much too large to cause Rayleigh scattering. So why does the sky look blue?
The answer is the size of the particles in the atmosphere. These particles are very small, much smaller than the wavelength of light. When the photons hit these particles, they scatter in all directions.
Some photons scatter towards the ground, and some scatter upwards into the sky. This is why the sky is blue most of the time.
Other colors of the sky
Now, you might be wondering why the sky is sometimes other colors. The answer is the size of the particles in the atmosphere and the sun’s angle.
When the sun is low on the horizon, the light has to travel through more atmosphere to reach us. This means the photons have to bounce off more particles before reaching our eyes.
The blue photons are scattered more than the red photons, so we see more blue light. This is why the sky is red and orange at sunrise and sunset.

Now that you know a bit about why the sky is blue, you can go outside and enjoy the beauty of a sunny day!