I think it's a funny coincidence that he says "Light acts as a medium of information transfer here.", because IMO this article is only a medium of info transfer from the source he links at the bottom (to be fair, at least he links it) without adding much.
I don't think there's anything wrong with making personal blog posts about learning well established concepts, but promoting them is the reason we have a million Medium/etc articles that are just regurgitating a paper without adding anything of substance.
Yes, wouldn't that only apply to soaking wet cloth? If it's just a little wet it still looks darker but not shiny, and there is no specific angle you can look at it and see the light source reflected. So it appears to still be diffuse in that state. Where does the light go?
It goes through, doesn't it? I can't find hard numbers, but basically Wet Clothes Don't Stop Sunburn. The UV rays don't bounce at all, unless it's off the skin. It mostly all turns to heat eventually (AFAIK).
Wow, is this the same reason why you're more prone to sunburn if you have water on you or are in a swimming pool? Does the light refracted under the surface of the water bounce around and hit your skin multiple times?
I think it is more what mannykannot said, combined with the fact that chlorine/salt/sand will also irritate skin, as well as the fact that sun reflecting off of water/glass/metal is not just reflecting visible light (sometime in the past few months there was a great thread on here with a guy talking about how they use mirrors to reflect sun onto solar panels where he works in Canada I think).
Snow sunburn is also a thing, IIRC snow can reflect as much as 90% of the UV. You can actually go 'snowblind' from this uv reflection.
This is a bit hand-wavey in its' description of light reflecting. One of the most mind blowing bits of physics I've ever learned is that photons do not actually "bounce" off of a surface like little balls. They are always absorbed and re-emitted. The actual photons that hit an object are not the same ones that eventually enter your eyes. The atoms in an object are stimulated by photons hitting them to then emit a new…
> The actual photons that hit an object are not the same ones that eventually enter your eyes.
For anything opaque, you should expect this, because otherwise how could you see something's color if you only saw the same photons as the light source it reflected?
IANAP but from my limited understanding (mostly reading Richard Feynman) light beam = stream of photons, they don't travel through entire body of glass prism without issue, they get absorbed and re emmitted along the way too (Which is what explains the different speed of light in different mediums)
I'm not convinced but even if we accept that explanation, why do all the atoms along the way emit the light in the direction it was travelling and then the ones at the surface suddenly emit it in a different direction?
They don't! That's why the thickness of th glass of affects it's reflectivity, and not the simple way you might guess. Read Feynman's QED book or watch the YouTube vidoes for a lay intro.
That doesn’t look right at all to me. Why the photon is then re-emitted in exactly the same direction that it would have if it was reflected rather than a random direction?
I think the two slit experiments indicate that a photon does exactly have a direction of travel?
Only after it arrives, so the situation's a lot more nuanced than that.
Having thought about it, I'm not sure if I agree. Light can reflect off of transparent crystals, which do not have the right electron energy levels for absorption (that's why they're transparent.) It's possible that the Feynman diagram of a reflection might involve the photon "going away and another one replacing it" (I don't know what the diagram looks like), but Feynman diagrams cannot be interpreted as sequences o…
They are not the same photons. They are emitted by the electron changing energy states after excitation of the incoming photon. But your intuition that there is some quantum weirdness is correct. Quantum Electrodynamics is the theory you're looking for. It unifies quantum mechanics and special relatively in the context of light/matter interaction. Given you seem to be familiar with Feynman. You're in for a treat! His…
Hydrogen atoms can't store photons that do not have the same wavelength as any of its spectral lines. Nonetheless, hydrogen gas has an index of refraction that is a continuous function of frequency, and as a result it can reflect light of any wavelength. Therefore, hydrogen does not store any energy for any length of time in the course of typical reflection. Even if the Feynman diagram for reflection looks like a combination of absorption and re-emission, if the absorption and emission process can't occur at separate times, then it is not right to say that one is followed by the other.
I'm not convinced but even if we accept that explanation, why do all the atoms along the way emit the light in the direction it was travelling and then the ones at the surface suddenly emit it in a different direction?
Probably it's just how the math works out. The atoms emit in all directions, however the waves traveling in all the other non-correct (according to reflections and refraction laws) directions cancel each other out, and only the ones with the new correct direction are still there / visible.
The little balls model perfectly explains why light reflects off a mirror at the same angle at which it arrived. How does the absorb-and-reemit model handle this?
"The Science Asylum" explains it: https://www.youtube.com/watch?v=cep6eECGtw4
That's almost exactly the same as Feynman's QED lecture from the 1980s(?), but with MSPaint animation instead of a chalkboard.
This is a bit hand-wavey in its' description of light reflecting. One of the most mind blowing bits of physics I've ever learned is that photons do not actually "bounce" off of a surface like little balls. They are always absorbed and re-emitted. The actual photons that hit an object are not the same ones that eventually enter your eyes. The atoms in an object are stimulated by photons hitting them to then emit a new…
Except light is a wave and not a particle so reflection is explained when you consider that.