Scattering of Light
The light is scattered by the small particle. The intensity of the scattered light varies with its wavelength. The blue color is scattered more than other colors due to its shorter wavelength. The scattering is responsible for the blue color of the sky.
A powerful torch, a transparent container of 20 cm length
Take water in a transparent container which is approximately 20 cm long (or wide). Add two or three drops of milk to the water and shine a powerful torch through the water. Look from a side of the container. You will see that the colour of the milk-water mixture changes with distance from the torch. Near the torch, the colour is milky blue. And at the other end, the colour is orange or red. If you add a few more drops of the milk, the colours become darker. Look at the face of the torch through the liquid. It will look reddish.