why is sky looking blue and clouds looking black?
The blue color of the sky was due to the process of Rayleigh Scattering. Since blue wavelengths are shorter than other colour wavelenghts, it get abosrbed by the gaseous molecules in the sky and radiated in all directions, scattering throughout the sky, thus transferring the blue wavelength to your eyes, thus you perceived the sky to be blue. The clouds are black because they block the light and also it is how our human eyes perceive light that cause the clouds to look black.
the sky is blue because blue is the colour that is reflected from the particles in the sky as the light hits them and clouds turn black/grey just because they are made up of moisture droplets and dirt/pollutant particles bind to them