Why can we see through glass? It’s a fundamentally basic questions that most of us never consider. Professor Phil Moriarty explains the phenomenon of glass transparency.
It won’t help anyone to do a Google search on why glass is transparent, because most of the answers they’ll get are wrong. Some will say that glass is like a liquid and its molecules aren’t as clustered together as they are in a solid, and therefore it allows light the get through, That, of course, is completely incorrect. The true reason has more to do with how a solid’s atoms are arranged, which then affects how its electrons are arranged. How those electrons stack up governs how light can pass through. When a photon, or light particle, passes through a solid, it will move its electrons to a higher level. While the electrons in an opaque solid can easily be moved to a higher energy level, those that are in a solid such as glass require a movement to an energy level that is basically impossible. As a result, light is not absorbed and passes right on through.