Reflection is the process by which light bounces off of a surface and is redirected in a different direction. This is why you can see your reflection in a mirror. When light reflects off of a surface, it can travel to areas that are not in direct line with the light source.
Refraction is the process by which light bends when it passes from one medium to another. This is why you can see a straw in a glass of water appear to be broken. When light refracts, it can travel to areas that are not in direct line with the light source.
Scattering is the process by which light is dispersed in all directions. This is why you can see light coming from a cloud even when the sun is not shining directly on it. When light is scattered, it can travel to areas that are not in direct line with the light source.
Emission is the process by which light is produced by a source. This is why you can see light coming from a light bulb. When light is emitted, it can travel to areas that are not in direct line with the light source.
All of these processes can contribute to the way that light reaches areas that are not in direct light.
