When is the photon reflected? And when does the photon just go through?

Question

I heard that if an object reflected light wave, we will see the color, depends on the light wave. But some materials, like glass and water, just let the photon go through.

But, how can we know if the photon is reflected or just go through? Both happen when the electrons don't need the energy to move to another energy level.

Please explain as clear as possible and use simple vocabulary. Sorry about my poor English.

Thanks in advance.

Answer 1

Not easy to answer. If the surface is a good conductor of electricity, the light induces electric currents which generate another electromagnetic wave in the opposite direction. The electric fields cancel at the surface. That's reflection.

See the second reference for some discussion of transparency. I think the basic idea is that in some large crystalline structures like diamond, and some amorphous structures like glass, the electrons are so thoroughly committed to the interatomic bonds that they can't absorb a photon.