the simple explanation for the reason light travels slower through water than a vacuum seems to be that when light is traveling through water the photons are absorbed by atoms for a short time and then emitted to be absorbed and emitted by other atoms.

in a chain reaction kind of progress, the light eventually is transmitted through the water.

 

is this just an oversimplification or is there something that causes the photon to keep moving in the same direction it was moving before being absorbed.

why isn't the photon emitted in a random direction ?

the simple explanation for the reason light travels slower through water than a vacuum seems to be that when light is traveling through water the photons are absorbed by atoms for a short time and then emitted to be absorbed and emitted by other atoms.

in a chain reaction kind of progress, the light eventually is transmitted through the water.

 

is this just an oversimplification or is there something that causes the photon to keep moving in the same direction it was moving before being absorbed.

why isn't the photon emitted in a random direction ?

 

That's the quantum explanation; the absorptions are into virtual states, and to conserve energy and momentum the photon is emitted in the same direction. If there was a resonance, and a photon were to be absorbed by a real state, the emitted photon could go in another direction, or the system could absorb the photon and relax in another way (e.g. creating phonons)