I want to know, why does light travel through water, glass etc and does not travel through opaque objects like wall, floor etc?
Why does glass doesn't absorb photons whereas opaque materials do?Opaque materials are absorbing the incoming photons, (and in doing so the material becomes slightly warmer).
Transparent materials allow some photons to pass through without being absorbed, but no material is perfectly transparent, if it is made thick enough an appreciable amount of photons still are absorbed.
The explanation is a bit too simple in the clip. He is talking in terms of discrete Energy Levels when they don't actually exist in condensed matter. There are Energy Bands in solids and not states. It would have been better to have said that, in a transparent substance, the next highest band is too high in energy for the electron to become excited into it.have a look at this video ....