[Deecart]

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.

[Deecart]

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.

[Deecart]

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.

[Deecart]

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.

[hamdani yusuf (OP)]

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.

[hamdani yusuf (OP)]

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.

[Bored chemist]

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.

[Bored chemist]

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".

[hamdani yusuf (OP)]

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?

[Bored chemist]

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

[hamdani yusuf (OP)]

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.

[alancalverd]

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.

[hamdani yusuf (OP)]

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.

[alancalverd]

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!

[hamdani yusuf (OP)]

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.

[alancalverd]

All good stuff, but the point is that you can measure ε for paraffin wax and it gives you the right answer for refraction!

[hamdani yusuf (OP)]

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.

[hamdani yusuf (OP)]

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.

[Bored chemist]

The correct answer to a video that says "which indicates FTL phenomenon." is "Oh no it doesn't.

[hamdani yusuf (OP)]

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.