Which types of scattering cause the sky to appear blue and clouds to look white?

The sky appears blue and clouds look white primarily due to Rayleigh and Mie scattering.

Rayleigh scattering occurs when sunlight interacts with molecules and small particles in the atmosphere. It is particularly effective for shorter wavelengths of light, which is why the blue light is scattered more than other colors. This scattering is responsible for the blue color of the sky on clear days.

Mie scattering, on the other hand, occurs when light interacts with larger particles, such as water droplets or dust, which are present in clouds. This type of scattering affects all wavelengths of light relatively equally, resulting in the white appearance of clouds. The larger water droplets in clouds scatter light in such a way that it blends all colors together, producing a white appearance.

By understanding these two types of scattering—Rayleigh for the blue sky and Mie for white clouds—it becomes clear why both phenomena occur.