... compared to a opaque materials electrons. Is it the amount of electrons in the atoms shells ? If you have a four inch cubic block of glass, and carbon, light passes through the glass no problem, but the carbon will absorb some red, yellow, green, and blue light, but if you look at the carbon absorption for light, not all blue, green, yellow, and red light get absorbed by carbon. glass cannot absorb high wavelengths of light. So if the two four inch cubic block of glass, and carbon, are placed in a dark room with no light hitting the blocks at all, and you just shined the colors of light at the carbon, that did not excite the electrons to a higher shell energy level, what would happen. Question 1. Does the light from the blue, green, yellow, and red pass through the carbon block, but I think you would just see the block of carbon just be black right, even though certain colors of light are passing through it, is this correct. All light colors pass through the glass no problem, so for the carbon things are different, its the energy of the electrons in the glass that cannot get exited for the light, so the light gets transmitted through the block of glass. So for the carbon, does its electrons either absorb more energy, or because it has 2 electrons in shell 1, and 4 electrons in shell two, silicone which is mostly what glass is made from has two electrons in shell 1,and 8 in shell 2, and 4 in shell 3. So it cannot be the amount of electrons I think just the energy of electrons, but can you explain why the energy levels are different for some electrons.