How 3 Materials Interact with Light.
I'm interested in how 3 materials:
Have you ever thought about why metal is shiny while paper is not? Why does light travel through glass but is stopped by metal? I've been trying to nail down these things in my mind. I looked at different articles and watched a number of videos but they only confused me because they seemed to contradict one another or oversimplify like they will tell the difference between 2 of the 3 but leave the one ambiguous. I was most confused about reflection. If absorption means the electron is raised to a higher energy state then I assumed that reflection meant it didn't get raised but then I would become more confused when they said glass is clear because the electron didn't get raised at all. So I understood the difference between absorption and transmission but what is reflection? Most articles only covered two of the three cases.
So it appears there are 3 types of interaction between light and electrons which produce 3 different results:
I'm also curious about metal. Metal reflects light because it's electrons are easily pushed to a higher wavelength and they fall back giving off a photon. The photon is emitted in all directions. So why do we see the reflection of a light at only a certain angle? If the light is leaving in all directions why are black things reflected in it? I can understand the highlights are the result of the fact that the re-emission of light creates little wavefronts which then add together to produce a copy of the original wave front just one that is moving in a different direction. But how do the black areas show up. Those black areas are emitting just as much as the light areas. If you move your eye to the right position you will see the light being emitted. They are still emitting light even when your eye isn't there. So why is it able to reflect black things? Photons don't bounce off stuff like balls because if they did it would make sense. The light wave hits the electrons and each electron emits a wavefront in all directions.
When there is black though at a certain point on a metal object in a certain direction it's because in that direction the waves are cancelling out. Still it's so black. you would think it would give off a little light. Paper emits light in all directions also and yet you see every part of a blank sheet of paper as one color (white) from all directions. The reason for this is that it's giving off random wave fronts. The light passes into the paper and emits it in random patterns but they are still noisy. There are still troughs and crests. Although most of those crests and troughs are cancelled out there is still a lot of troughs and crests generated, it's just those crests and troughs are totally random. There probably isn't anything left of the original colors it's just random noise however since these are random all the cones in your eye get stimulated. All the different wavelengths that hit (white is made up of all the colors) are re-emitted but they are now scrambled. Some of those troughs are of the blue wavelength and some are longer. They run the gamut of wavelengths because it's very random like noise on your TV. The reason it's random though is because even with flat surfaces like opaque glass or a smooth white tile in a bathroom the light penetrates to a depth equal to the red wavelength or more and as a result the light gets re-emitted randomly. The phases of the light are all mixed up so that while a lot gets cancelled out other crests and troughs get increased.
With chrome though the light is being emitted in very regular patterns because it's immediately re-emitted from the very top of the flat surface. The gaps between each spherical re-emission of light is no greater than the distance between atoms which is much smaller than the wavelength and will appear continuous. All the waves that hit the metallic surface are therefore re-created albeit in a different direction. For the black areas the light is leaving continuously and the crests and the troughs cancel out perfectly. It's not random at all. With paper the light is entering the surface and so the light is out of phase and yet it's not cancelling out the waves perfectly but randomly. With chrome though the waves get cancelled out perfectly in places and the wave-fronts are reconstructed perfectly in other directions. The reason they are cancelled out perfectly is that the atoms are next to each other and so the waves get out of phase continuously. It's like a continuous crest is created and yet following that crest half a wavelength later you will have a continuous trough. The continuous crest and a continuous trough will create a continuous cancelling out. Still the energy is still there (or is it?). I think you can use a diffraction grating to extract that energy perhaps. The atoms are still giving off photons but just not in that direction.
It makes me wonder at all the energy in space at one time. It's all there it's just mostly cancelled out. If you could somehow extract it then maybe it would be like getting energy from nothing. I guess though there are two reasons you might not see light.
Still there is something called the collapse of the wave function. It's like light is a signal that when it is received the whole wave-front it created collapses in the other directions. Only one electron can be excited by a whole wave-front of one photon. I have a theory or hypothesis that perhaps light is more like a signal that doesn't really have a direction other than all directions. It's more like a signal to other atoms and the atom closest gets the signal first. Perhaps this is regardless of the distance. Another possibility is that electrons are the ones carrying the photons. How would we know if whether or not that's the case since we need electrons to detect the photons. We are just taking the electron's word for it that the photons exist at all. Well I'm probably wrong about that though.
- Metal
- Glass
- Paper
Have you ever thought about why metal is shiny while paper is not? Why does light travel through glass but is stopped by metal? I've been trying to nail down these things in my mind. I looked at different articles and watched a number of videos but they only confused me because they seemed to contradict one another or oversimplify like they will tell the difference between 2 of the 3 but leave the one ambiguous. I was most confused about reflection. If absorption means the electron is raised to a higher energy state then I assumed that reflection meant it didn't get raised but then I would become more confused when they said glass is clear because the electron didn't get raised at all. So I understood the difference between absorption and transmission but what is reflection? Most articles only covered two of the three cases.
So it appears there are 3 types of interaction between light and electrons which produce 3 different results:
- Absorption
- Reflection
- Transmission
- Absorption: takes place when a photon hits an electron and moves it to a higher quantum state or shell--and remains there. Paper reflects all wavelengths however if you print on it the color of ink will absorb some of the wavelengths and if the ink is black it will absorb all wavelengths. I'm still not sure how it can remain there so let me know in the comments if you know the answer. I guess it can transmit the energy as heat. It can also reflect it at a wavelength you can't see. If it turns it into heat then that's still reflection because it sends it out in the infra red which is heat in all directions.
- Reflection: A photon hits an electron and moves it to a higher state and immediately the electron goes back to it's previous state. (Currently I find it confusing though since when it goes back to that lower state wouldn't it send the energy back in all directions? If so how to mirrors work if they are sending the light back in all directions? Metals are highly reflective because their electrons easily move about and have more freedom while with less reflective substances the electrons are more tightly bound so the light passes below the surface more.
- Transmission: With glass the light travels right through and this takes place because the electrons require more energy than visible light has in order to be bumped up even temporarily to a higher quantum state. The bonds in glass are much stronger than in metal. Glass and Crystals have similar properties. While glass just doesn't have a regular pattern to it's structure, silicon which it's made from does though and perhaps given time glass will eventually morph(which I heard it does very slowly) back to a regular molecular pattern. The electrons in glass and crystals aren't as easily messed with and so the electrons ignore the light and the light just passes through. The density of the electrons will cause light to slow down however perhaps due to relativistic effects. Perhaps just as gravity affects light the forces in the atoms cause light to slow down as it passes through. All materials are mostly empty space so rather than being surprised that light passes through some objects we should be more surprised that it has trouble passing through other materials.
I'm also curious about metal. Metal reflects light because it's electrons are easily pushed to a higher wavelength and they fall back giving off a photon. The photon is emitted in all directions. So why do we see the reflection of a light at only a certain angle? If the light is leaving in all directions why are black things reflected in it? I can understand the highlights are the result of the fact that the re-emission of light creates little wavefronts which then add together to produce a copy of the original wave front just one that is moving in a different direction. But how do the black areas show up. Those black areas are emitting just as much as the light areas. If you move your eye to the right position you will see the light being emitted. They are still emitting light even when your eye isn't there. So why is it able to reflect black things? Photons don't bounce off stuff like balls because if they did it would make sense. The light wave hits the electrons and each electron emits a wavefront in all directions.
When there is black though at a certain point on a metal object in a certain direction it's because in that direction the waves are cancelling out. Still it's so black. you would think it would give off a little light. Paper emits light in all directions also and yet you see every part of a blank sheet of paper as one color (white) from all directions. The reason for this is that it's giving off random wave fronts. The light passes into the paper and emits it in random patterns but they are still noisy. There are still troughs and crests. Although most of those crests and troughs are cancelled out there is still a lot of troughs and crests generated, it's just those crests and troughs are totally random. There probably isn't anything left of the original colors it's just random noise however since these are random all the cones in your eye get stimulated. All the different wavelengths that hit (white is made up of all the colors) are re-emitted but they are now scrambled. Some of those troughs are of the blue wavelength and some are longer. They run the gamut of wavelengths because it's very random like noise on your TV. The reason it's random though is because even with flat surfaces like opaque glass or a smooth white tile in a bathroom the light penetrates to a depth equal to the red wavelength or more and as a result the light gets re-emitted randomly. The phases of the light are all mixed up so that while a lot gets cancelled out other crests and troughs get increased.
With chrome though the light is being emitted in very regular patterns because it's immediately re-emitted from the very top of the flat surface. The gaps between each spherical re-emission of light is no greater than the distance between atoms which is much smaller than the wavelength and will appear continuous. All the waves that hit the metallic surface are therefore re-created albeit in a different direction. For the black areas the light is leaving continuously and the crests and the troughs cancel out perfectly. It's not random at all. With paper the light is entering the surface and so the light is out of phase and yet it's not cancelling out the waves perfectly but randomly. With chrome though the waves get cancelled out perfectly in places and the wave-fronts are reconstructed perfectly in other directions. The reason they are cancelled out perfectly is that the atoms are next to each other and so the waves get out of phase continuously. It's like a continuous crest is created and yet following that crest half a wavelength later you will have a continuous trough. The continuous crest and a continuous trough will create a continuous cancelling out. Still the energy is still there (or is it?). I think you can use a diffraction grating to extract that energy perhaps. The atoms are still giving off photons but just not in that direction.
It makes me wonder at all the energy in space at one time. It's all there it's just mostly cancelled out. If you could somehow extract it then maybe it would be like getting energy from nothing. I guess though there are two reasons you might not see light.
- Because the waves cancel out at that point
- I'm not sure if that has completely cancelled out the waves in that direction.
- Because there are no light waves at all.
Still there is something called the collapse of the wave function. It's like light is a signal that when it is received the whole wave-front it created collapses in the other directions. Only one electron can be excited by a whole wave-front of one photon. I have a theory or hypothesis that perhaps light is more like a signal that doesn't really have a direction other than all directions. It's more like a signal to other atoms and the atom closest gets the signal first. Perhaps this is regardless of the distance. Another possibility is that electrons are the ones carrying the photons. How would we know if whether or not that's the case since we need electrons to detect the photons. We are just taking the electron's word for it that the photons exist at all. Well I'm probably wrong about that though.
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