What is the difference between scattering and reflection ?

Scattering and reflection are both phenomena that occur when light or other forms of electromagnetic radiation interact with matter, but they differ in the way they alter the direction and propagation of the radiation.

Reflection is the process by which light or other electromagnetic waves bounce off a surface without being absorbed or scattered significantly. When light encounters a smooth surface, such as a mirror or still water, the incident light rays are reflected off the surface at the same angle at which they arrived, following the law of reflection. This results in a well-defined, specular reflection, where the reflected rays maintain their original coherence and direction.

Scattering, on the other hand, is the process by which light or other electromagnetic waves deviate from their original path after encountering an obstacle or interacting with particles in a medium. Scattering occurs when the size of the particles or the irregularities in the medium are comparable to the wavelength of the incident radiation. This causes the radiation to be redirected in various directions, resulting in a loss of coherence and a diffusion of the light energy. Scattering can occur in multiple ways, such as Rayleigh scattering, Mie scattering, or Tyndall scattering, depending on the size of the particles relative to the wavelength of the incident radiation.

In summary, reflection refers to the bouncing off of light waves from a smooth surface with minimal absorption or scattering, maintaining the original direction and coherence of the incident light. Scattering, on the other hand, involves the deviation and diffusion of light waves in various directions due to interactions with particles or irregularities in the medium, leading to a loss of coherence and redirection of energy.