Why light cannot pass through most solids?
372946
Actually, If you shine light on a steel door, the atoms that make up the surface of the door will absorb the photonic energy, and if they absorb enough photonic energy, they will emit the energy. Sometimes the newly emitted energy is outward away from the door, and sometimes the energy is emitted inward and propagated to atoms further into the doors structure.\n\nTo make thing more complicated, the energy is only emitted as photonic energy sometimes, when the atoms have the right amount of energy built up to release a quanta of photonic value. Other times the energy is emitted as heat energy. \n\nThe door is trying to propagate the photonic anergy through to the other side, however the atoms that comprise the door are capable of retaining a great deal of energy, and when they do release it, based on quantum mechanics, there is only a probability that it will be directed into and not out of the door.\n\nIf you quickly heat the atoms in a specific region ,(fill them up with energy), without giving them time to transfer the energy away, (blow torch) you can see the glowing red door on the other side.\n\nIn short, it is due the the energy retention strength of the atoms that make up the solid.
97822
i think sound energy can pass through a medium so should pass through opaque object. light energy is not transmitted through opaque objects only transparent objects so it will be reflected at the boundary. Degree of reflection would depend on the opaqueness of the object
1023210
It's not totally unaltered:\n\nThe most obvious characteristic of ordinary glass is that it is transparent to visible light (not all glassy materials are). This transparency is due to an absence of electronic transition states in the range of visible light, and because ordinary glass is homogeneous on all length scales greater than about a wavelength of visible light. (Heterogeneities cause light to be scattered, breaking up any coherent image transmission). Ordinary glass partially blocks UVA (wavelength between 400 and 300 nm) and totally blocks UVC and UVB (wavelengths shorter than 300 nm) due to the addition of compounds such as soda ash (sodium carbonate).
804004
Perhaps it is because red light has the least energy of all the colors of the visible spectrum.  It has the longest wavelength, thus the slowest frequency, slower than that of blue or violet, for example.  I don't know for sure if this is the reason the materials are not sensitive to it, though.
971516
When you light a block of glass, part of the light will be absorbed by the glass.\nIn other words, part of the photons will be absorbed by the glass.\nOther photons will be reflected back by the block of glass, and others will pass through it.\nThe lose of energy of your light ray will be seen as a reduction in the number of photons in the ray, in other words, in a reduction in the ray's INTENSITY. Not as a change in the light's frequency.\n\nHowever, the glass will absorb certain light frequencies better than other. (Each matter has its own "absorption graph").\nBecause of that, if your light ray is not a monochromatic one, it is possible that the ratio between the different light frequencies in the ray will change.
111323
I see the point in your question.  I think you are asking why  do we not see an aura of light, since light would still be passing around us.\n\nLight is an electromagnetic wave (OK, some might say rightly that this is debatable since it sometimes displays properties more accustomed to matter.  However, this dual nature does not imply that light is not an electromagnetic wave).\n\nThat said, one must understand that the e-m wave in itself is invisible.  It is the retina in our eyes which is sensitive to these rays.  Imagine this example.  Light a torch in a dark and clean room (no dust flying about!).  You would see the paper, but you won't see the light travelling from the torch to paper!  That is unless dust, or humidity, reflect this light and you would see a beam of light.  Similarly if you take a magnifying glass, you can see the image, but can you see the light coming out of that image? No.\n\nSo, though light would be passing around us, since nothing, except of course the Moon, satellites, and planets would be reflecting it, we cannot see it!
749920
Yes, that's why.  The first answerer is correct, too--we can't make a lens powerful enough to see an atom--but the reason why we can't is that the wavelength of visible light is larger than an atom.
217538
Each material absorbs different wavelengths of light. It turns out that glass an air absorb very little in the visual range of the spectrum (although they absorb in other regions). However, they do absorb some. If you had a piece of ordinary glass that was very thick, it wouldn't pass much light. In fact, one reason that mountains in a distance look blue is that the longer wavelengths are absorbed by the air. On the other hand, it is possible to have pices of metal that are so thin that they pass light.
297899
If you mean how are shadows formed, the answer is simple.  A solid object blocks light.  Since the light can't go through it, then the area all around it has light, but the area right behind it is dark.  \n\nSince light bounces around, it's not completely black inside the shadow.  Some light will still bounce in there and light it up a little, but it won't be as much light as the area around it.  Less light = shadow.
955526
Light moves slower through denser media because more particles get in its way. Each time the light bumps into a particle of the medium, the light gets absorbed which causes the particle to vibrate a little and then the light gets re-emitted. This process causes a time delay in the light's movement so the more particles there are (the more dense the medium), then the more the light will be slowed down.\n\nAs the light 'slows' down, it will then bends towards the normal.\n\nthink of a car with 4 wheels getting into a sand area from the road. as the one of the two front wheels hit the sand, it encounters resistance n hence slows down. however, the other three wheels are still moving at the normal speed. this results in the whole car moving forward but turned in the direction of the first wheel that was slowed down by the sand.
96084
Only real images can be projected since imaginary images only make light appear to originate from a point, light actually does pass through the real images location.
1074310
We can see through glass because light passes through it. Our eyes only see objects — chairs, the phone, your computer, or even tinted glass — by processing light waves reflected off the object or absorbed by it. \n\nLight is made up of waves of different sizes. But our eyes detect only certain wavelengths known as the visible spectrum, and each wavelength in the visible spectrum represents a different color. When something is clear, like glass, visible light passes straight through it without being absorbed or reflected. Wood, on the other hand, absorbs the light in wavelengths we can see. \n\nTo understand this on the atomic level, imagine electrons whizzing around in clearly defined paths, like cars on a racetrack. The racetracks are called energy levels, and they determine whether the material will absorb light. "Light is a photon and it has energy," says Carlo Pantano, professor of materials science and engineering at Penn State University. When the energy level of the electron is similar to the energy of the light, the electron absorbs the light. "That energy gets converted to heat," Pantano says. "That's why black things get hot." The electrons in a molecule of wood are at the right energy level to absorb visible light, but the electrons in a glass molecule are not. \n\nClear glass does not absorb visible light, but it does absorb other wavelengths: ultraviolet, which is what gives you a suntan, and infrared, or heat. But not all glass is clear. A stained glass window, for instance, may glow with all the colors of the spectrum — but we can still see through it. Remember, an object's color depends on which wavelengths of light are absorbed and which are reflected. \n\nGlass is colored by adding light-absorbing substances. Copper absorbs light in the red end of the spectrum, letting the blue end of the spectrum pass through. Adding copper to glass yields a blue pane. Chromium soaks up some red and blue wavelengths; glass spiked with chromium appears green. Because some visible wavelengths pass through colored glass, we can still see through it.
278787
in waves, therefore, in order to be transmitted it requires some medium to transmit the waves in. That's why sound can't travel through a vacuum such as outer space, for example
1158615
Hello,\n Air is , as we all know, matter in molecular (gaseous) state. Even in a very large volume of air, the number of molecules will be very very small compared to solid or liquid i.e; the density is less.\n  These molecules scatters as well as absorbs light. Considering a single molecule, the absorbtion is negligible compared to the light reflected by it. Molecules cannot be seen by our eyes. Reflected light being maximum, we see light and not darkness.This scattering is the reason we see light in the shades under trees etc, where no direct sunlight falls. Now, the light absorbed is used by its electrons to increase its energy levels.\n  Absorbtion is more when the air is filled with smoke and dust. They, being dense, absorbs more light and you see darkness.
876426
All objects that you can see absorb some light.  Black objects absorb all light while color objects absorb all but that spectrum of light.  Something white absorbs very little light.  If something absorbs no light, you will not be able to see it because no light is reflected back to your eye.
865196
simple it is because of refraction .\nas glass slab is more denser the speed of light is less \nas it comes out of glass into air (less denser than glass)speed increases
143804
Only light within the visible spectrum (450 nanometres (nm) wavelength, to about 700nm wavelength). \n\nOther light (infra red and above / ultraviolet and below) is not visible.