Transpareny of Glass ?

[coconuthead]

Hello freinds !

 

Can any one kindly explain me what properties of the molecules or atoms that make up the glass OR what phenomenon makes glass to transmit all light through them without being blocked as other solid materials do ?

 

I have searched for it on the web. But the explanations were too technical to understand (I am not a Physics person). Some sites explained it like this ----- " an absence of electronic transition states in the range of visible light" -------- What does this mean. Can any one explain it to me in simple language ?

 

Thank you very much !

[insane_alien]

ok, to start with, light is made up of these little particles called photons. these photons interact with the atoms of a material by shoving the electrons of the atoms about. These electrons only have a certain number of places they can be and each place takes a certain amount of energy to get there.

 

if a photon shoves an electron into a different place the photon is absorbed and the energy is what makes the electron jump. if this happens, light of this energy(frequency) will not pass through the material.

 

if the photon that hits the electron doesn't have the right amount of energy to shove it into a different place then it just passes on by as if nothing happened. these photons pass through the material.

 

in glass there are no places for the electrons to go that have the same energy as a photon of visible light so all the photons pass through and a few are reflected.

 

If you look at glass in the UV spectrum(we can't see it but we can make cameras that can. glass is completely opaque(you can't see through it at all)

this explains why you can't get a suntan in a greenhouse(no UV gets through)

 

This is a simplified explanation but its basically true.

[coconuthead]

Thank you so much Alien for the explanation !

 

Does that mean that, if we change the energy of the light or radiation striking the glass, such that, the photons can interact with the electrons of the glass, then we can make the glass look opaque ?

 

Also, conversely, does that mean that if we direct some low energy radiation or phenomenon towards a solid object like Steel, such that it DOES NOT have enough energy to strike off or interact with the material of steel and thus it just pass through, and had our eyes been sensitive to that kind of a radiation, then we could look through a steel wall ?

[Locrian]

Does that mean that, if we change the energy of the light or radiation striking the glass, such that, the photons can interact with the electrons of the glass, then we can make the glass look opaque ?

 

Yes. Quartz is clear in the optical frequencies, but tends to be opaque in the ultraviolet (though people sell quartz they say transmits there as well). As for steel, metals tend to be very difficult to image through with almost any frequency of light. The problem is that by the time you find something that will penetrate the steel, you get very specific kinds of information from the other side (if anything at all), which may not be useful. Of course this can be very complicated, and there are many tools out there.

[insane_alien]

sorry for the late reply but i've been on holiday.

 

1. the only wavelegnths(frequencies) that have the right amount of energy to intereact with the electrons in glass are invisible to our eyes. this inly means that we have to use a camera that can see these wavelegnths to observe the effects.

 

2. steel(and all other metals and metal alloys) are a whole different story...

the electrons in metals and alloys that bond the atoms together and the ones that the light would interact with, are all floating about in a kind of sea through out the metal. the has the strange effect of allowing practically ANY frequency of light to interact. this is why they appear silvery and are usually impervious to X-rays, ultraviolet, visible light, infra-red(well once you get to these longer wavelegnths its a bit different but close enough)