• Do you know the reasons for appearance the red colour of sun during sunrise and at sunset?

The atmosphere contains free molecules and atoms with different sizes. These molecules and atoms scatter light of different wavelengths which are comparable to their size. Molecules having a size that is comparable to the wavelength of red light are less in the atmosphere. Hence scattering of red light is less when compared to the other colours of light. The light from the sun needs to travel more distance in atmosphere during sunrise and sunset to reach your eye. In morning and evening times, during sunrise and sunset, except red light all colours scatter more and vanish before they reach you. Since scattering of redlight is very small, it reaches you. As a result sun appears red in colour during sunrise and sunset.

• Can you guess the reason why sun doesnot appear red during noon hours?

During noon hours, the distance to be travelled by the sun rays in the atmosphere is less than that compared to morning and evening hours. Therefore all colours reach your eye without much scattering. Hence the sun appears white during noon hours

Do you know?

Our beloved scientist and Noble prize winner, Sir C.V. Raman explained the phenomenon of light scattering in gases and liquids. He found experimentally that the frequency of scattered light by the liquids is greater than the frequency of incident light. This is called Raman Effect. By using this effect scientists determine the shapes of the molecules.

So far, we have learned some ideas of the light such as refraction, dispersion and scattering. These are wonderful phenomena occuring in our surroundings. When you observe any phenomena, try to resolve the problem and appreciate the wonderful world based on the behaviour of light.