Applications

Abstract

Sky under extended cloudiness looks grey with a uniform variation of transmitted light intensity. Isolated clouds look white on the background of a blue sky. This whiteness is primarily due to nonselective light scattering by water droplets in the visible. The solar light is composed of a mixture of waves having various wavelengths. A prism can divide the sunlight beam in a continuous colour spectrum. This is due to the change of the refractive index of the prism with the wavelength. Interestingly, clouds can also exhibit spectrally selective scattering if special conditions are met.