When a wave is passing medium containing discontinuities, I learned from Wiki, scattering means changing the direction from a straight trajectory, so does it include refraction, transmission and reflection? Does transmission means the part of wave that has passed the interface, and therefore include refraction and scattering, not reflection? Or transmission mean the part of wave still in the straight trajectory? What would possibly happen when a wave hits the interface of discontinuities? Reflection, refraction, absorption? anything else not mentioned? In the cases of Reflection, refraction, scattering and transmission, will the atom hit by the light absort the light and/or remit a new light? Thanks!