Naked Science Forum
On the Lighter Side => New Theories => Topic started by: hamdani yusuf on 08/09/2019 23:42:53
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These videos show why many explanations of refraction are wrong.
I'll show that the accepted explanation in those videos are still inaccurate.
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I'll show that the accepted explanation in those videos are still inaccurate.
Is there anything in particular you're waiting for?
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Is there anything in particular you're waiting for?
Nothing in particular. I was just occupied by other more urgent matters.
In video #1
from 7:06 mark, we get that amplitude of combined wave fluctuates, just like beat phenomenon. If the speed of first wave is very similar to the second wave, such as interface between vacuum and thin air, or glass and sunflower oil, we should receive low frequency beat. AFAIK, this is not observed in experiment.
from 8:20 mark, somehow the second wave changes the wavelength for no apparent reason. But curiously, the resultant wave have the same wavelength as the first wave.
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In video#2
from marker 9:37 The explanation goes on to assume that the electric field is p-polarized (parallel to plane of incident. In this case, your monitor screen). It doesn't show how it works for s-polarized light (perpendicular to your monitor screen).
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In my experiment using microwave, I can confirm that partial reflections by partial polarizers can produce phase shift of one polarization component over the other, which is shown by production of circularly polarized microwave from linearly polarized transmitter as the source. This indicates that one polarization component has changed its speed when travelling between those partial polarizers.
In the next video that I'm preparing, I'll show that speed change alone is not sufficient to produce change of direction. It is possible for light to change speed when passing through different media without changing its direction, even when the incoming angle is not 0.
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My model can be thought as an extention to the working principle of antenna, which can be shown clearly here.
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Light DOES NOT slow down in glass!
Light does NOT slow down when it goes from air to glass. Yet, it gets delayed. How?
The explanation offered in this video is more compatible with my own experiments using microwave transceiver, although there are still some discrepancies.
I expect to see massive revisions on physics textbooks in not so distant future. At least, refraction of X-ray by glass should be mentioned.
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I expect to see massive revisions on physics textbooks in not so distant future
I don't..
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I expect to see massive revisions on physics textbooks in not so distant future
I don't..
why?
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why?
Because we already know why the speed of light slows down when it passes through glass, water, etc. obviously.
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why?
Because we already know why the speed of light slows down when it passes through glass, water, etc. obviously.
Why X-ray seems to speed up when it passes through glass?
Have you seen the video?
“It is impossible for a man to learn what he thinks he already knows.”-
Epictetus
“It’s what we think we know that keeps us from learning.”― Claude Bernard
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Have you seen the video?
No, I haven't, but I'm aware of the effect of glass on a Xray beam.
So are most scientists.
So, as Origin said.
we already know why the speed of light slows down when it passes through glass, water, etc. obviously.
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interface between vacuum and glass...we should receive low frequency beat
To get a low frequency beat, you have to mix two frequencies together, in the same, non-linear medium.
- Vacuum and glass are not the same medium - they are two different media
- Vacuum is very linear (up to E field strengths that were only recently achieved (https://en.wikipedia.org/wiki/Schwinger_limit)), and common types of glass are pretty linear (provided you don't start melting it)
So I wouldn't expect to see beat frequencies, or that they would cause refraction.
https://en.wikipedia.org/wiki/Nonlinear_optics
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No, I haven't, but I'm aware of the effect of glass on a Xray beam.
What's your explanation?
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interface between vacuum and glass...we should receive low frequency beat
Where did I say that?
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Where did I say that?
Here
we should receive low frequency beat.
No, I haven't, but I'm aware of the effect of glass on a Xray beam.
What's your explanation?
More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am.
So this
I expect to see massive revisions on physics textbooks in not so distant future.
makes very little sense.
The stuff is already in the textbooks and has been since (at least) the 1960s.
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Have you seen the video?
No, the reason there is no need to see it is this statement you made:
"The explanation offered in this video is more compatible with my own experiments".
You are not physicist (probably haven't even taken a single physics course) and your posting history is full of errors and misconceptions, so if the video disagrees with mainstream physics and aligns with your ideas then it is not worth watching.
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interface between vacuum and glass...we should receive low frequency beat
To get a low frequency beat, you have to mix two frequencies together, in the same, non-linear medium.
- Vacuum and glass are not the same medium - they are two different media
- Vacuum is very linear (up to E field strengths that were only recently achieved (https://en.wikipedia.org/wiki/Schwinger_limit)), and common types of glass are pretty linear (provided you don't start melting it)
So I wouldn't expect to see beat frequencies, or that they would cause refraction.
https://en.wikipedia.org/wiki/Nonlinear_optics
That's why I rejected the explanation in the first video.
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More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am
Well that's pretty humorous, so apparently the video is accurate it's just that hamdani doesn't understand it.
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More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am.
Most physics textbooks explain refraction using Snell's law which is derived from Fermat's principle. Feynman's explanation is more similar to derivation using Huygen's principle. They leave the part of how the media change phase velocity of light unexplained.
https://en.m.wikipedia.org/wiki/Snell%27s_law
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More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am
Well that's pretty humorous, so apparently the video is accurate it's just that hamdani doesn't understand it.
What's even funnier is that you think you already understand it when you haven't even seen it.
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You are not physicist (probably haven't even taken a single physics course) and your posting history is full of errors and misconceptions, so if the video disagrees with mainstream physics and aligns with your ideas then it is not worth watching.
Your way of thinking is not scientific, speculative, and often committed logical fallacies, especially appeal to authority which tends to be dogmatic. Your blind faith to mainstream ideas made you fall into group thinking and herd mentality.
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What's your explanation?
Not sure, but i guess it has to do with the wavelength.
After some search i found this :
At very high frequencies, the value of electric permittivity is very slightly less than one.
https://www.quora.com/Why-is-the-refractive-index-of-x-rays-less-than-1
X-ray is a very high frequency wave.
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More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am.
Most physics textbooks explain refraction using Snell's law which is derived from Fermat's principle. Feynman's explanation is more similar to derivation using Huygen's principle. They leave the part of how the media change phase velocity of light unexplained.
https://en.m.wikipedia.org/wiki/Snell%27s_law
So, your "complaint" is that the school text books offer a less detailed 9and less complete) explanation than those written for university students.
What did you expect?
Once again, we are in "lies we tell to children" territory.
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often committed logical fallacies, especially appeal to authority
You don't know what that means do you?
We can probably assume- at least for the purpose of this post- that Einstein is an authority on physics.
If someone tells me "The speed of light is constant; Einstein says so" it is reasonable for me to believe it- because he is an authority.
But if someone tells me "Manchester is a bigger city than Liverpool; Einstein says so" it is not reasonable for me to believe it because he's good at physics, but I really don't know if he's any good at geography.
Only the second of those situations is a logical fallacy.
It is not a fallacy to say that physicists are good at physics.
And, while we are at it.
It is not "dogma" to believe experimental results.
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it's just that Hamdani doesn't understand it.
That's not a short list...
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What's your explanation?
Not sure, but i guess it has to do with the wavelength.
After some search i found this :
At very high frequencies, the value of electric permittivity is very slightly less than one.
https://www.quora.com/Why-is-the-refractive-index-of-x-rays-less-than-1
X-ray is a very high frequency wave.
The link just restates the question and cites experimental results. It doesn't show the underlying mechanisms based on first principles.
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often committed logical fallacies, especially appeal to authority
You don't know what that means do you?
We can probably assume- at least for the purpose of this post- that Einstein is an authority on physics.
If someone tells me "The speed of light is constant; Einstein says so" it is reasonable for me to believe it- because he is an authority.
But if someone tells me "Manchester is a bigger city than Liverpool; Einstein says so" it is not reasonable for me to believe it because he's good at physics, but I really don't know if he's any good at geography.
Only the second of those situations is a logical fallacy.
It is not a fallacy to say that physicists are good at physics.
There are many scientists. Sometimes they disagree with each others. You can choose one of them to follow, which implies choosing the others to ignore. If the reason for your choice is based on the number of followers, then it is unscientific choice.
It's possible that you end up with the correct model by choosing the most popular one. Or even by picking randomly. But they are unscientific reasons. We should choose a model based on its explanatory power, i. e. capable to explain more phenomena with less assumptions.
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The link just restates the question and cites experimental results. It doesn't show the underlying mechanisms based on first principles.
I agree that the common explaination i actualy get looks more like a "what" answer than a "how" answer.
It is surprising that because "the what" answer seem complicated for most peoples, they accept and confuse it with the "how" answer every smart people would require.
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It's possible that you end up with the correct model by choosing the most popular one. Or even by picking randomly. But they are unscientific reasons. We should choose a model based on its explanatory power, i. e. capable to explain more phenomena with less assumptions.
I think so.
Therefore, in the first place, we should not talk about "light".
Light is some very complex interaction of photons.
A laser beam is also some special association of photons.
In my opinion, we should first study and be able to explain the behavior of some single photon.
If we do so, and only rely on facts, we cant talk of photons traveling from one place to one other.
We need to agree that if we dont interact with the photon, its position, and even its reality, is unknown.
We can only do the deduction : There was a photon after it has disappeared.
Therefore i like to say that the photon is some virtual entity, until it is no more.
A strange entity...
Concerning the propagation of the single photon, we have to consider it as "a wave".
What it means (in my opinion but you could have some other) is that there is some particle, the photon, that travels into some spacetime, and the spacetime specific to this photon is expanding.
This "area" where the photon is traveling back an forth is expanding at the speed of light.
But the photon itself, within this area, is traveling much faster than the speed of light, relativ to the outside of the area.
This do not contradict any physical law, because within the area (localy) where the photon bounce back an forth (and this is why you have some "wave"...) the photon do not travel faster then the speed of light.
"The area" (the place where the photon exists as a particle) is some place where time do not flow at the same speed as outside the area.
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There are many scientists. Sometimes they disagree with each others. You can choose one of them to follow,
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or you can look at the evidence.But they are unscientific reasons. We should choose a model based on its explanatory power, i. e. capable to explain more phenomena with less assumptions.
OK, so what facts and observations are not explained by the current models in physics?
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So, your "complaint" is that the school text books offer a less detailed 9and less complete) explanation than those written for university students.
What did you expect?
Once again, we are in "lies we tell to children" territory.
I'm not the only one who complaint. The authors of the videos in the first post also think that we have misled children. They deserve better explanation. At least, they must be told where the model we told them fails.
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OK, so what facts and observations are not explained by the current models in physics?
With a lot of online sources, it's hard to decide which explanation is considered mainstream at a given point in time. You can find them in the first videos in this thread.
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With a lot of online sources, it's hard to decide
Who finds it hard to decide, and why?
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At least, they must be told where the model we told them fails.
OK, so tell us where the model fails.
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With a lot of online sources, it's hard to decide which explanation is considered mainstream at a given point in time. You can find them in the first videos in this thread.
Go to .edu sites, since those are generally university sites you can be reasonably sure the information there will be mainstream.
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Who finds it hard to decide, and why?
Anyone who does not have better information than the authors of those online sources.
You need a more trusted sources of information to reject or accept other sources of information.
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At least, they must be told where the model we told them fails.
OK, so tell us where the model fails.
You can find them in the first videos in this thread.
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Go to .edu sites, since those are generally university sites you can be reasonably sure the information there will be mainstream.
Here's the first link I got from online search.
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html
Refraction is the bending of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media. The amount of bending depends on the indices of refraction of the two media and is described quantitatively by Snell's Law.
It doesn't tell the mechanism for how the medium can change the light speed there. The last video I posted shows why it's false, using the refraction of X-ray from air to glass.
The first videos in this thread shows more examples. Have you watched them?
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Here's another link.
https://micro.magnet.fsu.edu/primer/java/refraction/refractionangles/index.html
As light passes from one substance into another, it will travel straight through with no change of direction when crossing the boundary between the two substances head-on (perpendicular, or a 90-degree angle of incidence). However, if the light impacts the boundary at any other angle it will be bent or refracted, with the degree of refraction increasing as the beam is progressively inclined at a greater angle with respect to the boundary. As an example, a beam of light striking water vertically will not be refracted, but if the beam enters the water at a slight angle it will be refracted to a very small degree. If the angle of the beam is increased even further, the light will refract with increasing proportion to the entry angle. Early scientists realized that the ratio between the angle at which the light crosses the media interface and the angle produced after refraction is a very precise characteristic of the material producing the refraction effect.
The refractive index of a transparent substance or material is defined as the relative speed at which light moves through the material with respect to its speed in a vacuum. By convention, the refractive index of a vacuum is defined as having a value of 1.0, which serves as a universally accepted reference point. The index of refraction of other transparent materials, commonly identified by the variable n, is defined through the equation:
n (Refractive Index) = c/v
where c is the speed of light in a vacuum and v is the velocity of light in the material. Because the refractive index of a vacuum is defined as 1.0, and light attains its maximum speed in a vacuum (which is devoid of any material), the refractive index of all other transparent materials exceeds the value of 1.0, and can be measured by a number of techniques. For most practical purposes, the refractive index of air (1.0003) is so close to that of a vacuum that it can be employed to calculate refractive indices of unknown materials. Materials with higher refractive indices slow the speed of light to a greater degree than those with lower refractive indices. In effect, these materials are said to be more refractive, and they exhibit a larger angle of refraction for incoming light rays passing through an air interface.
The explanation here is similar to previous one.
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If I make an optical fibre out of glass with a refractive index of 1.5 and I send a flash of light down a kilometer of this cable, how long does it take the flash to reach the other end?
What is the speed of light in that glass?
If you use one of these sorts of things to measure the depth of a swimming pool, do you get the right answer?
https://www.toolstation.com/dewalt-dwht77100-xj-laser-distance-measure-30m/p67627?store=AG&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=&pkw=&pmt=&gclid=Cj0KCQjwl92XBhC7ARIsAHLl9ak1eLlUzABZzcj2kekc_LMN7C-ixh7mcv0xwXPE-UhtrNAlFav1mK0aAoEFEALw_wcB&gclsrc=aw.ds
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It doesn't tell the mechanism for how the medium can change the light speed there. The last video I posted shows why it's false, using the refraction of X-ray from air to glass.
The first videos in this thread shows more examples. Have you watched them?
I suggest you figure out a way to get a physics degree. You seem truly interested in physics but watching youtubes and trying to make experiments with subpar equipment is only confusing you. Without a solid understanding of basic physics you will never understand the more complicated and nuanced concepts.
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If I make an optical fibre out of glass with a refractive index of 1.5 and I send a flash of light down a kilometer of this cable, how long does it take the flash to reach the other end?
What is the speed of light in that glass?
1.5 times the light needs to travel 1 km in vacuum.
2c/3.
If you use one of these sorts of things to measure the depth of a swimming pool, do you get the right answer?
https://www.toolstation.com/dewalt-dwht77100-xj-laser-distance-measure-30m/p67627?store=AG&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=&pkw=&pmt=&gclid=Cj0KCQjwl92XBhC7ARIsAHLl9ak1eLlUzABZzcj2kekc_LMN7C-ixh7mcv0xwXPE-UhtrNAlFav1mK0aAoEFEALw_wcB&gclsrc=aw.ds
No.
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It doesn't tell the mechanism for how the medium can change the light speed there. The last video I posted shows why it's false, using the refraction of X-ray from air to glass.
The first videos in this thread shows more examples. Have you watched them?
I suggest you figure out a way to get a physics degree. You seem truly interested in physics but watching youtubes and trying to make experiments with subpar equipment is only confusing you. Without a solid understanding of basic physics you will never understand the more complicated and nuanced concepts.
Questioning discrepancy between theory predictions and observation can be done anytime by anyone. No degree is needed.
Do you think X-ray travels faster through glass than air?
I pointed that the explanation in the video still contains discrepancies.
The explanation offered in this video is more compatible with my own experiments using microwave transceiver, although there are still some discrepancies.
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Are you aware that EM radiation has two velocities?
https://en.wikipedia.org/wiki/Phase_velocity
https://en.wikipedia.org/wiki/Group_velocity
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Questioning discrepancy between theory predictions and observation can be done anytime by anyone. No degree is needed.
No, but knowledge- perhaps acquired as part of a degree- is needed to understand those theories and see why there isn't really a discrepancy.
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Are you aware that EM radiation has two velocities?
https://en.wikipedia.org/wiki/Phase_velocity
https://en.wikipedia.org/wiki/Group_velocity
Yes. The question is, how do various matters change them differently?
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I think confusion has arisen in several minds by failing to distinguish between speed and velocity.
The path of a photon is the direction of its velocity vector. Its speed depends on Maxwell's equation v = 1/√εμ (note v is a scalar) and in free space c = v0 in all directions
For visible photons incident on a medium, v (vector) tends towards the normal, and as propagation depends on collective electron movements within the material, the refractive index generally increases with increasing photon energy (dispersion). But as Deecart has pointed out, ε < 1 at very high frequencies so the propagation direction can tend away from the normal, depending on the propagation mode, even if v (scalar) < c.
Interesting? Only that the phenomenon was completely described by a Peterhouse man 40 years before x-rays were discovered.
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PS it just occurred to me that you could look at x-ray refraction in terms of momentum transfer. Visible light just wiggles the electrons a bit so the wavelet analysis gives you a reasonable model of forward propagation, but x-ray photons transfer significant momentum, so conservation demands that the forward displacement of the substrate electrons is compensated by a lateral deflection of the propagation vector.
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But as Deecart has pointed out, ε < 1 at very high frequencies so the propagation direction can tend away from the normal, depending on the propagation mode, even if v (scalar) < c.
I guess you mean n<1.
The question is, how do various matters change light velocities differently?
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Interesting? Only that the phenomenon was completely described by a Peterhouse man 40 years before x-rays were discovered.
Why it's not widely acknowledged by physicists, as pointed out by the first videos here?
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PS it just occurred to me that you could look at x-ray refraction in terms of momentum transfer. Visible light just wiggles the electrons a bit so the wavelet analysis gives you a reasonable model of forward propagation, but x-ray photons transfer significant momentum, so conservation demands that the forward displacement of the substrate electrons is compensated by a lateral deflection of the propagation vector.
It sounds like an ad hoc explanation to me. How can it be used to explain other closely related phenomena, such as reflection, total internal reflection, absorption, and polarization?
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n is dependent on the more fundamental property, ε.
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Interesting? Only that the phenomenon was completely described by a Peterhouse man 40 years before x-rays were discovered.
Why it's not widely acknowledged by physicists, as pointed out by the first videos here?
You will have to ask them.
Lack of a proper education, perhaps? Failure to respect true genius? Political Correctness (Peterhouse was one of the last colleges to admit women)? Maxwell was considered a bit odd, socially, at the time.
More likely: Few people study both classical and x-ray optics.The refraction of high energy photons is small and has no practical application that I know of, and physics usually derives from engineering, not the other way around.
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How can it be used to explain other closely related phenomena, such as reflection, total internal reflection, absorption, and polarization?
It can't, but momentum transfer is the basis of the Mossbauer effect.
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You will have to ask them.
Lack of a proper education, perhaps? Failure to respect true genius? Political Correctness (Peterhouse was one of the last colleges to admit women)? Maxwell was considered a bit odd, socially, at the time.
More likely: Few people study both classical and x-ray optics.The refraction of high energy photons is small and has no practical application that I know of, and physics usually derives from engineering, not the other way around.
If the theory were accurate enough to be used as first principle in engineering, it would be widely used, because rejecting it would bring competitive disadvantages.
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How can it be used to explain other closely related phenomena, such as reflection, total internal reflection, absorption, and polarization?
It can't, but momentum transfer is the basis of the Mossbauer effect.
At least we know that there's still a gap in understanding of refraction.
We do not believe any group of men adequate enough or wise enough to operate without scrutiny or without criticism. We know that the only way to avoid error is to detect it, that the only way to detect it is to be free to enquire. We know that the wages of secrecy are corruption. We know that in secrecy error, undetected, will flourish and subvert.
J. Robert Oppenheimer
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At least we know that there's still a gap in understanding of refraction.
A more accurate statement is:
At least we I know that there's still a gap in [my] understanding of refraction.
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If the theory were accurate enough to be used as first principle in engineering, it would be widely used, because rejecting it would bring competitive disadvantages.
It is accurate and they do use it.
Did you think you had a point?
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Refraction is sufficiently well understood by those who need to, that we have microscopes, telescopes, spectacles, and in my case replacement eye lenses and varifocal specs, that work remarkably well. Anglers understand it well enough to be able to drop their bait in front of the fish, and aviators know about the apparent displacement of long-wave and medium-wave radio beacons. The guys who design camera lenses have been using chromatic dispersion data for as long as compound lenses existed - the popular tessar formulation being at least 120 years old.
The adverse refraction of x-rays is known to crystallographers. IIRC it isn't of much significance in industrial crystallography where you are usually comparing actual with standard diffraction patterns, but bent-crystal monochromators used for some research applications probably need a refraction correction. It's all a very old memory!
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At least we know that there's still a gap in understanding of refraction.
A more accurate statement is:
At least we I know that there's still a gap in [my] understanding of refraction.
I don't know if your understanding of refraction is correct or not, because you never told us here. But the first videos in this thread shows many of us misunderstand it, including professional physicists. If you think you have a better explanation, let us know. Now you can peacefully put up or shut up.
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because you never told us here.
He did, though he was a bit obscure about it.
That stuff about a man from Porterhouse referred to this guy
https://en.wikipedia.org/wiki/James_Clerk_Maxwell
and his equations.
https://en.wikipedia.org/wiki/Maxwell%27s_equations
which let you calculate refraction.
How come you didn't realise that?
Is it because you refuse to learn science?
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x-ray photons transfer significant momentum, so conservation demands that the forward displacement of the substrate electrons
The IXPE space telescope (launched end-2021) measures the polarization of X-Rays from astronomical sources.
https://www.space.com/nasa-ixpe-satellite-begins-gathering-science-data
Rather than detect X-Ray polarization by refraction, they monitor it by watching the direction electrons are ejected when the X-Ray photon hits a gas molecule.
https://ixpe.msfc.nasa.gov/detectors.html
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because you never told us here.
He did, though he was a bit obscure about it.
That stuff about a man from Porterhouse referred to this guy
https://en.wikipedia.org/wiki/James_Clerk_Maxwell
and his equations.
https://en.wikipedia.org/wiki/Maxwell%27s_equations
which let you calculate refraction.
How come you didn't realise that?
Is it because you refuse to learn science?
Why do we still have widely spread incorrect explanations as described in the first videos here?
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Why indeed? At least it's not as stupid, dangerous or widespread as religion.
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Why do we still have widely spread incorrect explanations as described in the first videos here?
Once again, we are in "lies we tell to children" territory.
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Why do we still have widely spread incorrect explanations as described in the first videos here?
Once again, we are in "lies we tell to children" territory.
What's the adult version?
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Why do we still have widely spread incorrect explanations as described in the first videos here?
Once again, we are in "lies we tell to children" territory.
What's the adult version?
https://en.wikipedia.org/wiki/Maxwell%27s_equations
Or, if you like, the one actually given as an explanation (rather than as an example of "wrong answers") in the first video.
Or the pretty similar version given here.
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https://en.wikipedia.org/wiki/Maxwell%27s_equations
The macroscopic equations define two new auxiliary fields that describe the large-scale behaviour of matter without having to consider atomic scale charges and quantum phenomena like spins. However, their use requires experimentally determined parameters for a phenomenological description of the electromagnetic response of materials.
It means that it doesn't really explain how materials behave to produce observable phenomena like refraction and absorption.
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Or, if you like, the one actually given as an explanation (rather than as an example of "wrong answers") in the first video.
Or the pretty similar version given here.
They are different. The first video explains refraction as result of superposition of waves with different speeds.
The last video explains refraction as result of superposition of original wave with reactionary wave from molecules of the medium, which have the same speed, but different phase. .
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Neither is an explanation. They are mathematical models that generate the observed result.
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Neither is an explanation. They are mathematical models that generate the observed result.
What else does it take to make an explanation?
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Maxwell's equations derive v from measurable quantities and hence explain why v varies with photon energy and substrate.
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Maxwell's equations derive v from measurable quantities and hence explain why v varies with photon energy and substrate.
Do you count them as explanation?
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The first video explains refraction as result of superposition of waves with different speeds.
Where does it say that (about light in glass)?
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Maxwell's equations derive v from measurable quantities and hence explain why v varies with photon energy and substrate.
Do you count them as explanation?
Yes. If you can derive an observable effect from a measurable quantity, you have explained the effect.
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Yes. If you can derive an observable effect from a measurable quantity, you have explained the effect.
How do you derive X-ray refraction in air-glass interface using Maxwell equation? What's the ε and μ?
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The first video explains refraction as result of superposition of waves with different speeds.
Where does it say that (about light in glass)?
Skip to 7:06, and continue watching.
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He makes a statement about combining waves.
If you combine waves of different speeds you get other, slower waves.
This is true; but irrelevant.
At about 8:55 he says that you get a combination of waves in light travelling through matter.
He doesn't say how they differ. He doesn't say if they differ in phase or speed.
In fact, they have the same speed, but different phase.
He could certainly have made it clearer than he did.
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He makes a statement about combining waves.
If you combine waves of different speeds you get other, slower waves.
This is true; but irrelevant.
At about 8:55 he says that you get a combination of waves in light travelling through matter.
He doesn't say how they differ. He doesn't say if they differ in phase or speed.
In fact, they have the same speed, but different phase.
He could certainly have made it clearer than he did.
But light propagates through optical fiber slower than through air. Hence the speed is different.
Even a professional physicist can't explain refraction clearly. Yet some non-scientists claimed to understand it completely without evidence.
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But light propagates through optical fiber slower than through air. Hence the speed is different.
Because ε and μ are different. What do you expect?
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Even a professional physicist can't explain refraction clearly.
This guy did.
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But light propagates through optical fiber slower than through air. Hence the speed is different.
Because ε and μ are different. What do you expect?
I expect he didn't write this.
In fact, they have the same speed, but different phase.
I hope you can learn something about context.
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I expect he didn't write this.
I'm sure he didn't write it; because I did.
I hope you can learn something about context.
The context is that I wrote it here.
He makes a statement about combining waves.
If you combine waves of different speeds you get other, slower waves.
This is true; but irrelevant.
At about 8:55 he says that you get a combination of waves in light travelling through matter.
He doesn't say how they differ. He doesn't say if they differ in phase or speed.
In fact, they have the same speed, but different phase.
He could certainly have made it clearer than he did.
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Even a professional physicist can't explain refraction clearly.
This guy did.
The explanation in the video is based on Feynman's Lecture. Yet, the video host was only recently get the intuitive explanation behind the details of math equations, even though he is a physics lecturer himself. Hence it doesn't seem like the standard explanation commonly given in mainstream physics class.
Somehow unscientific attitude was displayed here toward the video.
Have you seen the video?
No, the reason there is no need to see it is this statement you made:
"The explanation offered in this video is more compatible with my own experiments".
You are not physicist (probably haven't even taken a single physics course) and your posting history is full of errors and misconceptions, so if the video disagrees with mainstream physics and aligns with your ideas then it is not worth watching.
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I expect he didn't write this.
I'm sure he didn't write it; because I did.
I hope you can learn something about context.
The context is that I wrote it here.
He makes a statement about combining waves.
If you combine waves of different speeds you get other, slower waves.
This is true; but irrelevant.
At about 8:55 he says that you get a combination of waves in light travelling through matter.
He doesn't say how they differ. He doesn't say if they differ in phase or speed.
In fact, they have the same speed, but different phase.
He could certainly have made it clearer than he did.
The word "he" I wrote there refers to you, BC.
The word "you" I wrote there refers to Alan.
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This guy did.
There's a little problem in 16:40 time mark. It shows like the X-ray passing through the glass can reach the right side of the screen sooner than the X-ray passing through air.
A more reasonable explanation is that the X-ray phase is delayed more than half wave, creating an illusion that it was sped up less than a half wave. Hence, actually the X-ray propagates through glass even slower than ultraviolet light, which is slower than visible light.
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A more reasonable explanation is that the X-ray phase is delayed more than half wave, creating an illusion that it was sped up less than a half wave. Hence, actually the X-ray propagates through glass even slower than ultraviolet light, which is slower than visible light.
That may be reasonable, but it doesn't work.
It's not a fixed phase delay, it's a delay each time the photon encounters an electron.
If your idea was right then the apparent refractive index would depend on thickness.
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A more reasonable explanation is that the X-ray phase is delayed more than half wave, creating an illusion that it was sped up less than a half wave. Hence, actually the X-ray propagates through glass even slower than ultraviolet light, which is slower than visible light.
That may be reasonable, but it doesn't work.
It's not a fixed phase delay, it's a delay each time the photon encounters an electron.
If your idea was right then the apparent refractive index would depend on thickness.
Don't calculate per electron. Do it accumulatively per wavelength penetration depth.
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wavelength penetration depth.
That's a novel concept. Can you define and explain it?
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But light propagates through optical fiber slower than through air. Hence the speed is different.
Because ε and μ are different. What do you expect?
It seems this was obvious.
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wavelength penetration depth.
That's a novel concept. Can you define and explain it?
Let's say that the wavelength of the X-ray is 10 Angstrom, and the atomic spacing of the glass is 1 Angstrom. The phase of the X-ray is delayed by 7 Angstrom after penetrating the glass as far as 10 Angstrom. It creates an illusion that the phase is sped up by 30%. In average, each atomic layer of the glass delays the phase by 0.7 Angstrom.
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Don't calculate per electron. Do it accumulatively per wavelength penetration depth.
We do.
That was my point.
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Don't calculate per electron. Do it accumulatively per wavelength penetration depth.
We do.
That was my point.
If your idea was right then the apparent refractive index would depend on thickness.
The apparent refractive index would depend on thickness only if the glass is thinner than the wavelength of X-ray, which is impractical.
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A more reasonable explanation is that the X-ray phase is delayed more than half wave,
When?
is it half a wave at every interaction with an electron?
Half a wave for every millimetre of glass?
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A more reasonable explanation is that the X-ray phase is delayed more than half wave,
When?
is it half a wave at every interaction with an electron?
Half a wave for every millimetre of glass?
Let's say that the wavelength of the X-ray is 10 Angstrom, and the atomic spacing of the glass is 1 Angstrom. The phase of the X-ray is delayed by 7 Angstrom after penetrating the glass as far as 10 Angstrom. It creates an illusion that the phase is sped up by 30%. In average, each atomic layer of the glass delays the phase by 0.7 Angstrom.
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Why do we still have widely spread incorrect explanations as described in the first videos here?
The answer is straight forward.
Because we only provide explainations based on theory, not some proof based on some experimentation.
If there was some experimental proof, any physicist would, like everytime, use these experiments to explain the phenomenon.
Here, when we say that the light wave produce a change in the electronic situation of the matter, this is theory.
To proof that is is the case (so using some experiment) we would need to do the observation that there is a delay between the advance of the wave into the matter and the feedback effect.
So we have to do the observation to give the proof : When the firsts photons enter the matter, the light beam go straight and when the electron of the matter is affected by the beam (after some delay), the light beam do not go straight away any more, so it "curves".
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Why do we still have widely spread incorrect explanations as described in the first videos here?
The answer is straight forward.
Because we only provide explainations based on theory, not some proof based on some experimentation.
If there was some experimental proof, any physicist would, like everytime, use these experiments to explain the phenomenon.
Here, when we say that the light wave produce a change in the electronic situation of the matter, this is theory.
To proof that is is the case (so using some experiment) we would need to do the observation that there is a delay between the advance of the wave into the matter and the feedback effect.
I've mentioned many times previously, behaviors of electromagnetic waves can be better observed in longer wavelength where the size and shape of the antenna can be easily measured and visualized. By accepting that visible light and X-rays are simply electromagnetic wave with shorter wavelength, we can deduce the internal structure of the materials interacting with them.
Continuing my effort to understand the behavior of microwave in another thread, here I'd like to share experiments showing how radio wave behaves. I've prepared some experimental equipment, but didn't have enough time to execute the experiments yet, so for now I'll put this well made video from Harvard Natural Sciences Lecture Demonstrations first.
So we have to do the observation to give the proof : When the firsts photons enter the matter, the light beam go straight and when the electron of the matter is affected by the beam (after some delay), the light beam do not go straight away any more, so it "curves".
Where does it curve to?
How does it return to the original direction?
Have you watched the first video in this thread?
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Where does it curve to?
It do the refraction we are talking about (refraction = curving).
How does it return to the original direction?
It do not return to the previous direction.
It start with no refraction at all (because there are no photon already at place so the electrons are not already affected) : So the light beam go first straight away. THEN, with some delay, the light beam "curve" (do the refraction).
This is what we should see if the theorical explaination in the video is correct.
Have you watched the first video in this thread?
Yes.
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It do not return to the previous direction.
It start with no refraction at all (because there are no photon already at place so the electrons are not already affected) : So the light beam go first straight away. THEN, with some delay, the light beam "curve" (do the refraction).
This is what we should see if the theorical explaination in the video is correct.
How do the light know where to curve?
After initial bent on the interface of different media, the light goes in the straight line again. When exiting the refractive medium, the light goes back to the original direction if the front and rear surfaces are parallel.
Yes.
The video debunks your explanation, besides some others.
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The video debunks your explanation, besides some others.
What are you talking about ?
Here in the video : the physicist debunk the wrong explainations we found everywhere.
He is talking at time t=717 (so around 11:50) of the video about the "official", the theoritical explanation every scientist actually accept.
I am talking about the same explaination, this one starting at time t=717.
So he is not debunking "my" explaination (it is not mine it is his own).
What i say is : This is only some theoretical explaination and we dont really have some experience that confirm the detail of the phenomenon.
So people cant refer to this (missing) experience and easily give wrong explainations.
To confirm his explaination (the official one) i say that we should try to observe the delay between the INITIAL straight ligth beam and the FINAL curved one (of course we cant see this with our bare eyes).
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This is only some theoretical explaination and we dont really have some experience that confirm the detail of the phenomenon.
But we do. We can measure ε for all sorts of materials and all sorts of frequencies, and the refraction of electromagnetic radiation likewise.
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But we do. We can measure ε for all sorts of materials and all sorts of frequencies, and the refraction of electromagnetic radiation likewise.
Yes i know it.
But measuring ε do not explain anything.
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I am talking about the same explaination, this one starting at time t=717.
So he is not debunking "my" explaination (it is not mine it is his own).
How would you explain refraction of X-ray in glass, which is refracted to the opposite direction than visible light?
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But measuring ε do not explain anything.
It tells you how "rigidly" the electrons are held in the material.
It explains why materials containing bigger atoms- like lead- have high refractive indexes.
The outer electrons in a lead ion will be far from the nucleus compared to, for example, those in a calcium ion.
Because they are further from the nucleus, they are less strongly held and can interact more strongly with the em radiation.
And thus they create a secondary emission with a larger amplitude. So they effectively slow the light down more .
This is why lead glass is prized for ornamental work because of its sparkle.
You might think that ε doesn't explain anything, but that's only because you do not understand the science.
You can also consider the variation of ε with frequency and get an insight into dispersion..
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But we do. We can measure ε for all sorts of materials and all sorts of frequencies, and the refraction of electromagnetic radiation likewise.
How do you measure ε for all sorts of materials and all sorts of frequencies?
How is it affected by environmental factors like temperature and pressure, also external electric and magnetic fields?
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How do you measure ε for all sorts of materials and all sorts of frequencies?
Why not google that?
Why do you have this aversion to actually finding stuff out for yourself?
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How would you explain refraction of X-ray in glass, which is refracted to the opposite direction than visible light?
In fact this is not particular to x-ray ("the fact that it bends in the opposite direction").
And you can have the "normal" way if you start the light beam in the glass : It will bend "normaly" wen coming out of the glass and enter in the air.
You can also use vacuum with glass instead of air with glass and probably you will also have the "normal bending".
Or you can start your light in the air and shoot into the vaccum or start your light in the vaccum and shoot in the air : you will have opposite directions of the bending.
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You might think that ε doesn't explain anything, but that's only because you do not understand the science.
So you do not understand how science work.
Science need real experiments specificaly designed to show something particular.
100 years ago this is how scientists did (actually they use less this method...)
Science do not rely only on reasoning : Doing so is doing philosophy or at least mathematic when playing with properties only.
The fact that you dont understand that the refraction phenomenon need some additionnal experimentation shows that you dont understand how experiments are designed and why we do experiments.
Per example (roughly said), one experience someone need to do is : Sending 2 light beam of different intensities (one photon only would be the lightest "beam") and observing how the two beams refract : Is there some interaction between their actions ?
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So you do not understand how science work.
I listed some of the things thatmeasuring ε explains...
I was able to do that because those explanations form part of science.
Whereas the you wrote this
But measuring ε do not explain anything.
The fact that you dont understand that the refraction phenomenon need some additionnal experimentation
What additional experiments do you think we need?Science do not rely only on reasoning
Guess again.
Some bits of science were derived by reasoning.
https://en.wikipedia.org/wiki/Thought_experiment
Galileo famously did the "tower of Pisa" experiment in order to convince other people; but he already knew what the answer must be.
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How do you measure ε for all sorts of materials and all sorts of frequencies?
How is it affected by environmental factors like temperature and pressure, also external electric and magnetic fields?
Second-year undergraduate physics laboratory textbooks will get you a long way in this field, but manufacturers of electronic components (particularly cables) and systems (particularly radar) have more precise instrumentation.
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Guess again.
Some bits of science were derived by reasoning.
https://en.wikipedia.org/wiki/Thought_experiment
Galileo famously did the "tower of Pisa" experiment in order to convince other people; but he already knew what the answer must be.
Read again.
He dident already know (scientists do not know like that, only mathematicians and philosopher do), he supposed he was right, or there would be some paradox.
It is not because you THINK there is a paradox that you can change a theory : You must proove physicaly that ONE possibility to solve the paradox is better then some OTHER possibility to solve it:.
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Your wikipedia link say exactly the opposite you are saying :
Although the extract does not convey the elegance and power of the 'demonstration' terribly well, it is clear that it is a 'thought' experiment, rather than a practical one. Strange then, as Cohen says, that philosophers and scientists alike refuse to acknowledge either Galileo in particular or the thought experiment technique in general for its pivotal role in both science and philosophy. (The exception proves the rule – the iconoclastic philosopher of science, Paul Feyerabend, has also observed this methodological prejudice.[9]) Instead, many philosophers prefer to consider 'Thought Experiments' to be merely the use of a hypothetical scenario to help understand the way things are.
The pure reasoning helps to create some new insights, but when you do so, it remains a hypothesis.
It can help scientists to create new PHYSICAL DEMONSTRATIONS (SCIENCE=EXPERIENCE).
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What additional experiments do you think we need?
Some experiences linked with the verbal explanation.
Science is not only a matter of an expsilon value in a formula, it is the mater of how phenomenons are build.
Per example the refraction formula do not take in account the temporality of the full phenomenon, but unfortunatly the explanation use temporality : So the theoritical explanation is not well linked with the real phenomenon (per example).
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What additional experiments do you think we need?
Some experiences linked with the verbal explanation.
Science is not only a matter of an expsilon value in a formula, it is the mater of how phenomenons are build.
Per example the refraction formula do not take in account the temporality of the full phenomenon, but unfortunatly the explanation use temporality : So the theoritical explanation is not well linked with the real phenomenon (per example).
What additional experiments do you think we need?
OK, this time try answering the question with examples of the additional experiments you think we need.
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Read again.
He dident already know (scientists do not know like that, only mathematicians and philosopher do), he supposed he was right, or there would be some paradox.
OK. I read
"At the time when Viviani asserts that the experiment took place, Galileo had not yet formulated the final version of his law of falling bodies. He had, however, formulated an earlier version which predicted that bodies of the same material falling through the same medium would fall at the same speed.... While this story has been retold in popular accounts, there is no account by Galileo himself of such an experiment, and many historians believe it was a thought experiment."
from
https://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment
But you are missing the point.
You say "he supposed he was right, or there would be some paradox.".
And, because we know that reality does not create paradoxes, he knew he was right.
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OK, this time try answering the question with examples of the additional experiments you think we need.
I already gave you 2 experiments that "should" (at least this is my opinion) be done to validate the theoritical explanation, but it looks like you already know what you read before you read, like gallileo.
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And, because we know that reality does not create paradoxes, he knew he was right.
You are wrong again.
Whe are not talking about the reality here (we are not philosopher), we are talking about the REPRESENTATION of the reality.
And these representations, like these scientists use, need to be coherent. Thats all.
So we know that we can not have paradox within our representation.
Because we use logic (or it would be the end of the science, no logic, no science)
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Galileo's published thought experiment should have been sufficient to disprove the Aristotelian hypothesis since if it were true you would generate not one but two very different results simultaneously from the same trial. For the uninitiated:
If heavy objects fall faster than light ones, cut a stone into two unequal parts. The heavy part will fall faster than the light one. Now tie them together. The light piece slows down the heavy one. But the heavy piece speeds up the light one. Or the whole assembly falls faster than either of its parts.
Fortunately there is no evidence that he actually did the Pisa experiment, since the effect of air resistance would indeed have slowed the lighter object more than the heavier one and thus set science back until David Scott demonstrated the truth of the thought experiment on the Moon in 1971.
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He had, however, formulated an earlier version which predicted that bodies of the same material falling through the same medium would fall at the same speed....
Everybody know this anecdote.
And you guess what ?
Every scientist design his own experiment having PREVIOUSLY done some reasoning.
Very rarely they do their experience by random.
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Fortunately there is no evidence that he actually did the Pisa experiment, since the effect of air resistance would indeed have slowed the lighter object more than the heavier one and thus set science back until David Scott demonstrated the truth of the thought experiment on the Moon in 1971.
What experience ?
Where he drop something from up the tower ? This one is folklore, he never did something like that.
He used bullets on an inclinated ramp, so the speed was low, and he used as a chronometer his own heart pulsation.
By chance he dident used bobsleigh ! Or he would have discovered some other law...
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I already gave you 2 experiments
OK.
An experiment is a set of things that are done in order to see what happens.
What did you propose should actually be done?
Obviously, to be useful they need to be "new" experiments which haven't been done before in some way.
If an experiment has been done, it is not an "additional" experiment because it doesn't add anything.
So it can't be an answer to the question.
Quote from: Bored chemist on Today at 13:59:05
What additional experiments do you think we need?
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What did you propose should actually be done?
It dont have to give you some additional experiment.
It is you who pretend that the theoritical explanation given in the video is the truth.
I am sure you already have said this many times : Within science, it it to the one that states something to proove it.
Myself i only say that i never heard about any experimentation that proove this explanation.
So it is, in my opinion, only some interpretation of low value, without any observation.
What experimentations remember you to proove this interpretation ?
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It dont have to give you some additional experiment.
You do if you want to support your assertion The fact that you dont understand that the refraction phenomenon need some additionnal experimentation shows that you dont understand how experiments are designed and why we do experiments.
Are you now accepting that the fact that I don't think we need further experiments is because we have done them?
Do you also accept that I actually do understand refraction quite well?
And do you accept that I also know about experiments?
Within science, it it to the one that states something to proove it.
You stated this
"The fact that you dont understand that the refraction phenomenon need some additionnal experimentation shows that you dont understand how experiments are designed and why we do experiments."
Prove it.
Prove that we "need some additionnal experimentation".
Myself i only say that i never heard about any experimentation that proove this explanation.
That looks a lot like what I said earlier
You might think that ε doesn't explain anything, but that's only because you do not understand the science.
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You do if you want to support your assertion
It is amusing to see that you dont understand that it is no me who is doing some assertion.
Are you now accepting that the fact that I don't think we need further experiments is because we have done them?
You have not showed anything like that.
Do you also accept that I actually do understand refraction quite well?
I am now quite sure you dont understand how refraction work.
My opinion is that you are not a scientist but an engineer.
And do you accept that I also know about experiments?
Sure, if you accept that i know how to change lead into gold.
You only pretend and never proove anything.
Prove that we "need some additionnal experimentation".
Proove yourself that we have done the experiments that confirm the explanations we have in the video.
I myself dont need to proove anything, i am only saying that the explanation need a proof.
If there was some experiment the guy in the video would have used it to confirm his assertion , and so would you also.
So i suppose nobody never did those experiements.
That looks a lot like what I said earlier
So now you admit that we never did any experiment that permit to confirm the explanation ?
Try to remain coherent.
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I myself dont need to proove anything
You said earlier that you do.
Within science, it it to the one that states something to proove it.
Perhaps you should go away and think about it.
Come back when you have made up your mind.
It is amusing to see that you dont understand that it is no me who is doing some assertion.
Here, yet again, is the assertion which you made.
The fact that you dont understand that the refraction phenomenon need some additionnal experimentation shows that you dont understand how experiments are designed and why we do experiments.
Sure, if you accept that i know how to change lead into gold.
Well, it's not very practical but...
https://www.scienceabc.com/eyeopeners/can-we-transform-lead-into-gold.html
Now you know.
You have not showed anything like that.
I have repeatedly asked you what new experiments we would need.
You still refuse to answer.
Why is that?
So i suppose nobody never did those experiements.
How do you think the guy came to his conclusions without data?
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My opinion is that you are not a scientist but an engineer.
Well, in reality, I'm a scientist. That's what I have been paid for these last 30 years or so.
Prior to that I studied chemistry at Oxford.
I know stuff (for example, I know that you can make lead into gold).
I have knowledge- or scientia.
I'm also able to display ingenuity.
So I guess I might be some sort of engineer, but I have no formal qualifications as one.
Just out of curiosity, what qualifications and experience do you have?
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So now you admit that we never did any experiment that permit to confirm the explanation ?
That's not what I said, is it?
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What experience ?
Don't ignore the word "no" in the first line of my post!
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Well, it's not very practical but...
https://www.scienceabc.com/eyeopeners/can-we-transform-lead-into-gold.html
Now you know.
So you think i dont know this pretty obvious thing (even low student know this actually)...
I was just saying that to make you understand something, but forget it...
You said earlier that you do.
No i dident.
If i can help you, there are the words "at least".
Perhaps you should go away and think about it.
Come back when you have made up your mind.
I have already tried to understand how science work many years, so yes i dont need some delay to understand it.
But you do, and it is probably why you ask me to delay my intervention ?
Here, yet again, is the assertion which you made.
No, i already explained it to you 3 times.
I have repeatedly asked you what new experiments we would need.
You still refuse to answer.
I have proposed 2 new experiments, you 0 experiment and you continue to say that there are some experience already done... Just give us the reference instead of talking about you.
How do you think the guy came to his conclusions without data?
He probably repeated what he heard, this is what priest and engineer do : They repeat the dogma.
And you, you know how ? (perhaps you also can read in the guys minds...)
Well, in reality, I'm a scientist.That's what I have been paid for these last 30 years or so.
Prior to that I studied chemistry at Oxford.
No, you pretend to be.
The proof : You are not understanding the importance of experiment versus the theory and confuse between principle, hypothesis and scientific facts.
So you are some engineer.
We dont need to explain 3 times the same with no result to a scientist..
That's not what I said, is it?
Stop with the blabla, the fact that you are some scientist or not is not very interresting : Just show us the experiences = facts.
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He probably repeated what he heard, this is what priest and engineer do
You have clearly never met an engineer. Priests, politicians and philosophers are forms of parasite, not to be confused with those of us who use science to improve the human condition. Fortunately there is a lot of reliable scientific data on which one can base sound designs without having to repeat basic experiments. People who ignore good data, or make promises based on hope rather than information, fall into the parasitic category. If they don't know the facts, parasites make excuses, engineers make measurements.
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I have proposed 2 new experiments
Where?
Quote them.
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why you ask me to delay my intervention ?
To give you time to work out if things need to be proved or not.
Because you say they do
Within science, it it to the one that states something to proove it.
And then you say they don't.
I myself dont need to proove anything,
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So you think i dont know this pretty obvious thing (even low student know this actually)...
Yes.
I think you didn't know about it.
Because, if you knew about it, you would not have used it as an example of something "impossible", would you?
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No, you pretend to be.
I really am a scientist. I have a beard and glasses. I even have a white coat somewhere.
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And you, you know how ?
I didn't make any claim about him so I'm not the one who needs to prove anything about him.
On the other hand, you said "So i suppose nobody never did those experiements.
And, once again we are in the realms of you making unsupported claims.
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the fact that you are some scientist or not is not very interresting
Then why did you raise the issue?
Stop with the blabla
Pointing out your errors is not " blabla"; it's science.
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You have clearly never met an engineer. Priests, politicians and philosophers are forms of parasite, not to be confused with those of us who use science to improve the human condition.
Perhaps you already met engineers but you clearly dident understand what they do.
Priests "use" the result of science too you know.... They have a house, drive cars, drink in bottle, take some baths, cook, travel in planes, and use some phones. Or do you think they live like prehistoric men ???
Engineers "use" the result of science too, like everyone here on earth.
A scientist at the oposite do not only use the result of science : It create science
This is the main difference of scientist.
Engineers add technology to actual technology.
Scientists add science to actual science.
You are sure you really met some scientist ?
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Where?
Quote them.
Too tired to read ?
Use your strength to read instead of writing pointless things.
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And then you say they don't.
No, try to understand.
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Yes.
I think you didn't know about it.
Because, if you knew about it, you would not have used it as an example of something "impossible", would you?
This is false logic used by the sophists.
The reality is : I have used this as an example not because it is impossible but "for some other reason" (I already have explained this to you...)
So you say this is impossible that i say this, because " and you cite you own understanding" (believing you are knowing better what i have in my own mind... very funny).
But what you dont understand is : I have clearly writen this, so you should at least admit this fact : It is possible to say this (unlike your belief)
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I really am a scientist. I have a beard and glasses. I even have a white coat somewhere.
Me too and my beard is surely longer then yours.
Not sure this will help to understand refraction but at least you are funny.
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I didn't make any claim about him so I'm not the one who needs to prove anything about him.
On the other hand, you said "
So now you dont understand what you said.
Funny.
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Then why did you raise the issue?
I was talking about the need of experiments in science.
Not about the fact that you are (was...) a scientist or not.
It is you that claim to be a scientists : So you must be right and i must be wrong : This is some other sophistical argument.
Try to understand the discussion before flooding.
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Pointing out your errors is not " blabla"; it's science.
What errors ?
I only want to see the experiments that lead to the explanation (it looks like itr is the official one within the physicists) of the refraction.
You are not a physicist, so perhaps you never heard of these experiments.
You dont need to answer if you dont know.
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How do you measure ε for all sorts of materials and all sorts of frequencies?
Why not google that?
Why do you have this aversion to actually finding stuff out for yourself?
To check how your logic flows.
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In fact this is not particular to x-ray ("the fact that it bends in the opposite direction").
It can be done with microwave and metamaterials.
Visible light can also show this behavior with microscopic metamaterial.
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Where?
Quote them.
Too tired to read ?
Use your strength to read instead of writing pointless things.
Admit it.
You have not actually suggested any useful experiments.
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How do you measure ε for all sorts of materials and all sorts of frequencies?
Why not google that?
Why do you have this aversion to actually finding stuff out for yourself?
To check how your logic flows.
OK, as a student experiment in the 80s I made a series of measurements of the permittivity of a set of solutions of dinitrochlorobenzene (I think) in cyclohexane, and also of the pure solvent with a view to calculating the dipole moment of the molecule and thus working out which isomer it was (There are other, better, ways to do that but it was a student practical).
I did it by pouring the solutions into the space between the plates of a capacitor and measuring the change in capacitance.
My vague recollection now (decades later) is that the frequency we were using was of the order of 1MHz..
It would have been easy enough, in principle to use other frequencies.
So the "logic" I'm using is simply
"science knows how to measure stuff".
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My vague recollection now (decades later) is that the frequency we were using was of the order of 1MHz..
It would have been easy enough, in principle to use other frequencies.
How do you measure ε at the frequency of visible light and X-ray?
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My vague recollection now (decades later) is that the frequency we were using was of the order of 1MHz..
It would have been easy enough, in principle to use other frequencies.
How do you measure ε at the frequency of visible light and X-ray?
There are probably whole books written about it, but you could start here.
https://en.wikipedia.org/wiki/Dielectric_spectroscopy#Atomic_polarization
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There are probably whole books written about it, but you could start here.
https://en.wikipedia.org/wiki/Dielectric_spectroscopy#Atomic_polarization
The article doesn't mention what are actually measured, how to calculate ε from the results, and what are the justifications for the formula.
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My vague recollection now (decades later) is that the frequency we were using was of the order of 1MHz..
It would have been easy enough, in principle to use other frequencies.
How do you measure ε at the frequency of visible light and X-ray?
Up to a few GHz, you can plot the reactance of a capacitor versus frequency. At that stage you can also demonstrate the refraction of a microwave beam (as you have done yourself, with some very neat videos) and show how that correlates with the measured permittivity of the dielectric. Once you are into the submillimeter range it's generally easier to measure refraction than ε directly, and as far as we know there is no discontinuity between millimeter, infrared, visible and x-radiation - it's all the same stuff.
Then you calculate ε from what you know about the electronic structure of your material and find that it fits the measured value of refractive index.
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At a glance, these videos don't seem to provide useful information related to refraction, and how materials change the phase of electromagnetic waves.
Following videos show interaction of microwave with partial polarizer.
This video introduces a new type of apparatus to explore microwave optics. The partial polarizing filter passes through microwave oscillating perpendicular to its axis while only partially blocks/reflects microwave oscillating parallel to its axis.
This video demonstrates axis rotation by partial polarizer.
Here we tried to produce circularly polarized microwave by using two partial polarizers to generate phase shift in vertical axis while leaving horizontal axis undisturbed.
The last video shows the effect of birefringence, which means that one polarization axis has changed its phase compared to the other. It shows that phase changing requires interaction from at least 2 layers of conductors.
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I'm sure we discussed refraction some time ago, around one of your videos with microwaves and a dielectric block - poyethylene? If not, I probably have it in my undergraduate notes, but I've no idea where they are now!
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I'm sure we discussed refraction some time ago, around one of your videos with microwaves and a dielectric block - poyethylene? If not, I probably have it in my undergraduate notes, but I've no idea where they are now!
I think I only used paraffin block to show refraction of microwave, other than metamaterials using various shapes of metals.
youtu.be/nfYDiqiH5mU
This video shows that microwave can also experience refraction, just like normal optics.
The hardest part in making this video was molding the paraffin wax prism. But this worth the effort, since it will be used in several videos to come, which investigate total internal reflection and evanescent wave.
There are several videos for the sequel to this one.
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All good stuff, but the point is that you can measure ε for paraffin wax and it gives you the right answer for refraction!
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I have uploaded three more videos investigating behavior of microwave. This time I use meta-material.
The first is constructing meta-material to demonstrate interference by partial reflector
Second, we emulate refraction in microwave using meta-material, which is a multilayer metal grating
Lastly, reconstructing prism for microwave using meta-material to demonstrate refraction and internal reflection.
NB: This is not an April fool
These are videos showing experiments on refraction of microwave using metamaterials.
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All good stuff, but the point is that you can measure ε for paraffin wax and it gives you the right answer for refraction!
Does it give the correct answer to this video?
My next video try to replicate previous demonstration of refraction by meta-material. Instead of tubular metal, this experiment uses flat metal strip as basic unit of the meta-material. Interesting things are observed, especially apparent refractive index less than 1, which indicates FTL phenomenon.
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The correct answer to a video that says "which indicates FTL phenomenon." is "Oh no it doesn't.
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The correct answer to a video that says "which indicates FTL phenomenon." is "Oh no it doesn't.
It indicates FTL if you accept Fermat's principle. Otherwise, it doesn't.
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These are videos showing experiments on refraction of microwave using metamaterials.
All attempts to emulate refraction using metamaterial require pretty complex structure, which would be hard to express in simple equations. Simpler metamaterial structure such as two dimensional partial polarizers can not show the effect of refraction, but it can show the change of direction which is different than a simple reflection. Hopefully, by understanding the diffraction effect better, we can improve our understanding about refraction as well.
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Dear Hamdani,
I am late to see your original post.
To be honest, I think contemporary physics cannot yet explain the actual physical mechanism that gives the property of light refraction - the change in direction as found in Snell's law. It cannot be properly explained because we still almost have no real understanding of what light is; there may be claims otherwise by some people, but I don't buy them.
I personally is very interested in the answer. I will go through the earlier posts to see what have been written.
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More or less the one given in that video- in which the guy cites Feynman's books on the subject.
Those books are older than I am.
Most physics textbooks explain refraction using Snell's law which is derived from Fermat's principle. Feynman's explanation is more similar to derivation using Huygen's principle. They leave the part of how the media change phase velocity of light unexplained.
https://en.m.wikipedia.org/wiki/Snell%27s_law
Textbooks cannot yet explain the physical cause of refraction, why light speed slows down in optical medium causing the change in light direction.
It's easier to do string theory then to explain the physical cause of the laws governing the refraction of light.
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Textbooks cannot yet explain
Well... they can't explain it to you.
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Textbooks cannot yet explain
Well... they can't explain it to you.
Sure! The texbook could explain special relativity to me. Time dilation, etc., but the explanation still mean nothing to me. It does not matter to me if the whole world accepts special relativity. I don't. Don't ask why!
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Then we won't.
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Then we won't.
You can't blame me. Bored chemist was dismissive - sarcastic.
I come here to ask questions which I don't understand. In science we are free to hold differring opinions, even views completely at odd with what all the universities hold dear. The ONLY criterion is we are completely honest to our self - and this is verry, very difficult.
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In science we are free to hold differring opinions, even views completely at odd with what all the universities hold dear. The ONLY criterion is we are completely honest to our self - and this is verry, very difficult.
No.
The important criterion is that the opinions are consistent with the evidence.
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In science we are free to hold differring opinions, even views completely at odd with what all the universities hold dear. The ONLY criterion is we are completely honest to our self - and this is verry, very difficult.
No.
The important criterion is that the opinions are consistent with the evidence.
No! People who don't believe in the Almighty God cannot be honest! They will always argue without knowing when to stop. Even when you give them evidence the size of an elephant, a dishonest person will still insist he sees no elephant.
So honesty is the foremost criterion. It is for this reason that Newton's Principia can stand the test of time for more than 300 years without equal.
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People who don't believe in the Almighty God cannot be honest!
The God portrayed in the Bible is inconsistent with our observations.
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It is for this reason that Newton's Principia can stand the test of time for more than 300 years without equal.
Except for general relativity which is better than equal because it fits better with observation.
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People who don't believe in the Almighty God cannot be honest!
The God portrayed in the Bible is inconsistent with our observations.
If only your are humble and honest, else you will observe nothing.
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It is for this reason that Newton's Principia can stand the test of time for more than 300 years without equal.
Except for general relativity which is better than equal because it fits better with observation.
If there is a poll, I'll vote otherwise.
Much of physics is a matter of opinion - just like voting for the US president.
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Much of physics is a matter of opinion
Not really, no.
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Much of physics is a matter of opinion
But not every opinion is the same. Some can get you a job, or college entrance. Some can get you killed.
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If there is a poll, I'll vote otherwise.
It's not a poll it is a statement of fact
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Except for general relativity which is better than equal because it fits better with observation.
If there is a poll, I'll vote otherwise.
Much of physics is a matter of opinion - just like voting for the US president.
I think your prejudice is showing.
Measurements are not opinions just because you don’t like the results.
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Except for general relativity which is better than equal because it fits better with observation.
If there is a poll, I'll vote otherwise.
Much of physics is a matter of opinion - just like voting for the US president.
I think your prejudice is showing.
Measurements are not opinions just because you don’t like the results.
[/quote]
No. It is all a matter of opinion and faith and belief in the experimenters.
Take the discovery of the Higgs boson. Yes! They claimed they found it through experiments - meaning they have done measurements and detected the Higgs. But then many people "vote" against their "measurements" and dismiss the work of particle physics. They hold the "opinion" that the "mesaurements" cannot be trusted.
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Fortunately, science does not depend on consensus. 100 Nazi professors signed a letter criticising Einstein's Jewish theory of relativity. A journalist asked for his reaction: "Had I been wrong, one student would have been enough."
Whether you like the result or not is irrelevant. The most important part of an experimental science paper is the description of the method, which must be sufficiently explicit to allow a skilled technician to build the equipment and replicate the measurement. If you want to prove that the emperor has no clothes, just publish a photo of his willy.
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But then many people "vote" against their "measurements" and dismiss the work of particle physics.
You can't "vote against" a measurement. That's silly.
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But then many people "vote" against their "measurements" and dismiss the work of particle physics.
Those people as are known as idiots.
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No. It is all a matter of opinion and faith and belief in the experimenters.
That sounds like conspiracy theory talk.
But then many people "vote" against their "measurements" and dismiss the work of particle physics.
The Moon wouldn't stop existing if people voted against its existence.
They hold the "opinion" that the "mesaurements" cannot be trusted.
You mean like the "opinion" of flat-Earthers?
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This video explains reflection in similar way to antenna model. Explanation for refraction would be the sequel I'm anticipating.
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A lot of optical illusions can be explained by Fermat's principle of least time, but why does light obey it? On a fundamental level, it all comes down to quantum mechanics, specifically quantum optics, where we use the famous "Feynman path integral formulation" to explain light through photons.
Here's a pinned comment by the author.
Clarification: In my quantum animations, that is not multiple photons taking different paths. It is a single photon taking multiple paths simultaneously. We're releasing only one photon at a time. Adding those phasor arrows together gives us the probability of receiving a single photon at any given moment.
Minor Correction: I show the paths leaving the source at the same time and arriving at the detector at different times, when it should actually be the other way around. Paths that take more time should be leaving the source earlier in order to arrive at the detector at the same time as the others. The reason we can add the phasor arrows together is because the paths arrive at the detector at the same time.
This video explains refraction as the result of path integral of each individual photon. Although it doesn't explain the mechanism for how the media can change the speed of light in them.
Regarding the minor correction, if a photon's paths were leaving the source at different time, they would be leaving from different positions in case the source is moving.
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This video explains refraction as the result of path integral of each individual photon. Although it doesn't explain the mechanism for how the media can change the speed of light in them.
Usual problem. You need Maxwell to determine the speed of propagation of light as a wave, and Planck to describe the interaction of a photon with a receptor. No big deal.
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This video explains refraction as the result of path integral of each individual photon. Although it doesn't explain the mechanism for how the media can change the speed of light in them.
Usual problem. You need Maxwell to determine the speed of propagation of light as a wave, and Planck to describe the interaction of a photon with a receptor. No big deal.
Maxwell's equation doesn't describe the relationship between permittivity of a medium and its internal microstructure. It's obtained empirically.
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True. But it also applies in vacuo where there is no microstructure. Hence c is considered to be a fundamental constant.
It would be possible in theory to calculate ε and μ for real materials, but what's the point? It is done for artificial metamaterials.
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The point is, having an accurate and precise model of the physical reality gives us the ability to predict and design systems that we need to achieve our goals more effectively and efficiently. Trial and error can often give useful results, but we should be able to achieve it more efficiently.
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The point is, having an accurate and precise model of the physical reality gives us the ability to predict and design systems that we need to achieve our goals more effectively and efficiently. Trial and error can often give useful results, but we should be able to achieve it more efficiently.
Thank you Captain Obvious.
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The point is, having an accurate and precise model of the physical reality gives us the ability to predict and design systems that we need to achieve our goals more effectively and efficiently.
You are using a computer which could not have been made without accurate models.
So you should know that such models already exist.
Have you not been payting attention?
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You are using a computer which could not have been made without accurate models.
So you should know that such models already exist.
Do you know what models that they are using?
Are they the same as what we usually find in common physics textbooks or online sources?
What can you say about different explanations for refraction of light which were posted in the earlier part of this thread?
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Are they the same as what we usually find in common physics textbooks or online sources?
Yes.
Where did you think the engineers learned them from?
Ancient scrolls?
Mystic spell passed down from master to apprentice?
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Are they the same as what we usually find in common physics textbooks or online sources?
Yes.
Where did you think the engineers learned them from?
Ancient scrolls?
Mystic spell passed down from master to apprentice?
Which one is it?
Do you know that they are contradicting one another?
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Do you know that they are contradicting one another?
If I ask you to provide examples am I going to have to remind you about "lies we tell to children" again?
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Do you know that they are contradicting one another?
If I ask you to provide examples am I going to have to remind you about "lies we tell to children" again?
A bad thing about lies is that they need more lies to cover them up.
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If you rely on contradictory models you won't be able to make anything that works. This computer works, so I assume it was built with the use of models that do not contradict one another.
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Do you know that they are contradicting one another?
If I ask you to provide examples am I going to have to remind you about "lies we tell to children" again?
A bad thing about lies is that they need more lies to cover them up.
Or, as with LWTTC, the truth , but later on when they understand.
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If you rely on contradictory models you won't be able to make anything that works. This computer works, so I assume it was built with the use of models that do not contradict one another.
Computer designers can make computer works without knowing why light changes its speed and direction during refraction.
Do you realize that Apollo mission used Newton's model?
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Computer designers can make computer works without knowing why light changes its speed and direction during refraction.
Except if they use optical fiber couplers, which I certainly have done.
Do you realize that Apollo mission used Newton's model?
Up to a point, except that all the solid state devices rely on quantum phenomena, not continuum mechanics, and Newton wasn't too explicit about the combustion of liquid hydrogen or re-entry ablation. His theory of television seems a little shaky too.
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Computer designers can make computer works without knowing why light changes its speed and direction during refraction.
No.
The design of modern computers relies on modeling the "bits of wire" as transmission lines.
This sort
https://en.wikipedia.org/wiki/Transmission_line
rather than
https://en.wikipedia.org/wiki/Electric_power_transmission
And such models depend on knowing the speed at which the signals travel along the lines.
And that depends on the refractive index (and dispersion) of the insulating materials at the frequencies involved.
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Let's assume that someone knows the correct answer to why light changes its speed and direction during refraction. What prevents them from revealing it to the public?
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Let's assume that someone knows the correct answer to why light changes its speed and direction during refraction. What prevents them from revealing it to the public?
Nothing.
But they have not.
So your premise is incorrect by reductio ad absurdum
We can conclude that nobody "knows the correct answer to why light changes its speed and direction during refraction".
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It might just be something to do with ε and μ, but, like Maxwell, I'm just guessing.
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Let's assume that someone knows the correct answer to why light changes its speed and direction during refraction. What prevents them from revealing it to the public?
Nothing.
But they have not.
So your premise is incorrect by reductio ad absurdum
We can conclude that nobody "knows the correct answer to why light changes its speed and direction during refraction".
Then it's an opportunity for us to be the first to know, by doing research on this topic.
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It might just be something to do with ε and μ, but, like Maxwell, I'm just guessing.
They are empirical values, which makes them more like measurable effects instead of the cause.
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Let's assume that someone knows the correct answer to why light changes its speed and direction during refraction. What prevents them from revealing it to the public?
Nothing.
But they have not.
So your premise is incorrect by reductio ad absurdum
We can conclude that nobody "knows the correct answer to why light changes its speed and direction during refraction".
Then it's an opportunity for us to be the first to know, by doing research on this topic.
No.
It's grounds to ask what the guy who said we could make the assumption was thinking.
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It might just be something to do with ε and μ, but, like Maxwell, I'm just guessing.
They are empirical values, which makes them more like measurable effects instead of the cause.
They are, in principle, calculable.
The actual cause is arithmetically complex but fundamentally, this sort of thing.
https://www.motioncontroltips.com/four-laws-of-electromagnetism-you-should-know/
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This video tries to answer the question based on Feynman's lecture.
You can't explain prisms without understanding springs | Optics puzzles part 3
How the index of refraction arises, and why it depends on color.
Sections:
0:00 - The standard explanation
3:14 - The plan
5:09 - Phase kicks
8:25 - What causes light?
13:20 - Adding waves
16:40 - Modeling the charge oscillation
20:59 - The driven harmonic oscillator
26:57 - End notes
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X-rays "faster" than the speed of light, and more refractive index questions | Optics puzzles part 4
Timestamps:
0:00 - Why slowing implies bending
3:36 - Recap for how slowing happens
5:08 - Birefringence
6:19 - The barber pole
8:20 - When the refractive index is less than 1
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https://en.m.wikipedia.org/wiki/Sellmeier_equation
The Sellmeier equation is an empirical relationship between refractive index and wavelength for a particular transparent medium. The equation is used to determine the dispersion of light in the medium.
(https://upload.wikimedia.org/wikipedia/en/thumb/4/4f/Sellmeier-equation.svg/345px-Sellmeier-equation.svg.png)
Refractive index vs. wavelength for BK7 glass, showing measured points (blue crosses) and the Sellmeier equation (red line)
The X-ray should be on the left in the diagram.
The equation is pretty good at predicting the refractive index. Unfortunately, the article doesn't show it's theoretical derivation.
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For characterization of glasses the equation consisting of three terms is commonly used:(https://wikimedia.org/api/rest_v1/media/math/render/svg/0034c16a3f6f5a905e376c8ffa37dffbd2ad8c77)
As an example, the coefficients for a common borosilicate crown glass known as BK7 are shown below:
Coefficient Value
B1 1.03961212
B2 0.231792344
B3 1.01046945
C1 6.00069867?10−3 μm2
C2 2.00179144?10−2 μm2
C3 1.03560653?102 μm2
https://en.m.wikipedia.org/wiki/Sellmeier_equation
Out of curiosity, I plotted the equation into Wolfram Alpha. When x is not specified, the curve doesn't seem like anything shown in Wikipedia article.
https://www.wolframalpha.com/input?i=plot+sqrt%281%2B1.04*x%5E2%2F%28x%5E2-0.006%29%2B0.23*x%5E2%2F%28x%5E2-0.02%29%2B1.01*x%5E2%2F%28x%5E2-104%29%29+
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=77687.0;attach=34172)
When x is specified between 0.2 and 2, the curve looks more like in the article.
https://www.wolframalpha.com/input?i=plot+sqrt%281%2B1.04*x%5E2%2F%28x%5E2-0.006%29%2B0.23*x%5E2%2F%28x%5E2-0.02%29%2B1.01*x%5E2%2F%28x%5E2-104%29%29+from+0.2+to+2
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=77687.0;attach=34174)
Extrapolation for X-ray should cover shorter wavelength.
https://www.wolframalpha.com/input?i=plot+sqrt%281%2B1.04*x%5E2%2F%28x%5E2-0.006%29%2B0.23*x%5E2%2F%28x%5E2-0.02%29%2B1.01*x%5E2%2F%28x%5E2-104%29%29+from+0+to+0.2
(https://www.thenakedscientists.com/forum/index.php?action=dlattach;topic=77687.0;attach=34176)
It should occur close to the origin of the graph, corresponding up to 0.01 micrometer wavelength.
Roughly, X-rays have a wavelength ranging from 10 nanometers to 10 picometers
https://en.wikipedia.org/wiki/X-ray