Question

How do you appreciate the role of molecules in the atmosphere for the blue colour of the sky?

Answer 1

1. Scattering of sunlight through molecules of atmosphere is the reason for the blue of the sky.
   
2. Our atmosphere contains atoms and molecules of different sizes.
   
3. According to their sizes they are able to scatter different wavelength of light.
   
4. For example, the size of the water molecule is greater than the size of the $N_2$ or $O_2$
   
5. It acts as scattering centre for other frequencies which are lower than the frequency of blue light.
   
6. Blue colour scatters more than other colours.
7. In the absence of molecules there will be no scattering of sunlight and the sky will appear dark.
8. We should appreciate the molecules which are scattering centres.