[alancalverd]

So far, nobody has produced a better geometric construction than Huygens for predicting diffraction.  If it ain't busted, don't fix it.

The problem with epicycles is that they purported to be an explanation, not a predictive construction, and implied a mechanical structure for which there was no evidence. We still use a sort of epicycle mathematics to make remarkably accurate tide tables but they are under continuous revision as everyone realises that there are nth order effects that are easier to measure than to calculate..   

[hamdani yusuf (OP)]

So far, nobody has produced a better geometric construction than Huygens for predicting diffraction.  If it ain't busted, don't fix it.

The problem with epicycles is that they purported to be an explanation, not a predictive construction, and implied a mechanical structure for which there was no evidence. We still use a sort of epicycle mathematics to make remarkably accurate tide tables but they are under continuous revision as everyone realises that there are nth order effects that are easier to measure than to calculate..   

How does it produce reflection?

[alancalverd]

Every point at which the wavefront is reflected is treated as the source of the reflected wavelets.

Remember, as always, that Huygens is a geometric construction that mimics what happens, not an explanation of how it happens.

[hamdani yusuf (OP)]

Every point at which the wavefront is reflected is treated as the source of the reflected wavelets.

Remember, as always, that Huygens is a geometric construction that mimics what happens, not an explanation of how it happens.

Can it explain reflection by a polarizer?
My experiment shows that incoming microwave is almost completely reflected by the polarizer, despite the gap between conductors in the polarizer grid are much larger than the diameter of the conductors themselves.

[alancalverd]

Can it explain reflection by a polarizer?

Once again, it is a geometric construction, not an explanation.

[hamdani yusuf (OP)]

Can it explain reflection by a polarizer?

Once again, it is a geometric construction, not an explanation.

How do you geometrically construct the result of reflection by a polarizer?

[hamdani yusuf (OP)]

I asked Google Bard about the difference between diffraction and interference of light. IMO, the answer is better than many other sources I quoted in earlier posts.

what are the differences between diffraction and interference of light?

Diffraction and interference are both wave phenomena that occur when light passes through an opening or around an obstacle. However, there are some key differences between the two.

Diffraction is the bending of waves around an obstacle or through an opening. This occurs because waves can interfere with themselves, and when they do, they can create new patterns of light and dark. Diffraction is a property of all waves, including light, sound, and water waves.
Interference is the superposition of two or more waves. When two waves interfere, they can either add together to create a brighter wave (constructive interference) or cancel each other out to create a darker wave (destructive interference). Interference is a property of waves that have the same frequency and wavelength.

Diffraction   
Bending of waves around an obstacle or through an opening   
Property of all waves   
Creates new patterns of light and dark   

Interference
Superposition of two or more waves
Property of waves that have the same frequency and wavelength
Can create brighter or darker waves

[hamdani yusuf (OP)]

Property of all waves

This answer made me ask follow up question. Does diffraction occur in guitar string wave?

Yes, diffraction occurs in guitar string waves. When a guitar string is plucked, it vibrates and produces a wave that travels along the string. This wave is a longitudinal wave, which means that the particles of the string move back and forth in the same direction that the wave is traveling.

As the wave travels along the string, it diffracts around the bridge and nut, which are the two points where the string is attached to the guitar. This diffraction causes the wave to spread out and create a wider pattern of vibration.

The amount of diffraction that occurs depends on the wavelength of the wave and the size of the opening that the wave is passing through. The shorter the wavelength and the smaller the opening, the more diffraction will occur.

Diffraction is an important phenomenon that affects the sound of a guitar. It helps to create the wide, rich sound that is characteristic of a guitar.

I was interested about the waving guitar string, not the sound caused by vibration of the string. Thus I modified the question. Does diffraction occur in guitar string wave in vacuum?

No, diffraction does not occur in guitar string waves in a vacuum. Diffraction is the bending of waves around an obstacle or through an opening. This occurs because waves can interfere with themselves, and when they do, they can create new patterns of light and dark. However, sound waves, such as the waves created by a guitar string, cannot travel through a vacuum. Sound waves require a medium to travel through, such as air or water. Without a medium, sound waves cannot propagate and therefore cannot diffract.

However, if the guitar string were in a medium, such as air, then diffraction would occur. For example, if the guitar string were plucked in a room, the sound waves would diffract around the walls of the room and create a pattern of sound waves in the room. This pattern would be similar to the interference pattern created by light waves.

It doesn't seem to notice that its answer contradicts its previous claim.

[varsigma]

Two distinct phenomena shouldn't be confused just because they often come together. As long as they can occur separately, the distinction should be kept clear.

I think, in the age of quantum information science, that it doesn't pay to get too attached to a particular view or picture.
It shouldn't be something that becomes . . . precious to you.

For instance, the Aharonov-Bohm effect. Is this distinct from an interference effect? A diffraction effect? Is it something  else?

I know a guy (who probably knows a guy) who appears to believe it's about whether you can put things in bottles--a test of physicality. He's looking for one bottle to rule them all. pfft.

p.s. ChatGPT, or Bard, is bound to contradict itself, it isn't able to understand what that is.

[hamdani yusuf (OP)]

For instance, the Aharonov-Bohm effect. Is this distinct from an interference effect? A diffraction effect? Is it something  else?

https://en.m.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect

The Aharonov?Bohm effect, sometimes called the Ehrenberg?Siday?Aharonov?Bohm effect, is a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential (φ, A), despite being confined to a region in which both the magnetic field B and electric field E are zero.[1] The underlying mechanism is the coupling of the electromagnetic potential with the complex phase of a charged particle's wave function, and the Aharonov?Bohm effect is accordingly illustrated by interference experiments.

The experiment shows an additional effect on top of diffraction and interference effects.
Basically, we can add other effects as well, such as reflection and polarization to our designed experiments. But they should not confuse us about the definitions and boundaries of each effects.

[hamdani yusuf (OP)]

I think, in the age of quantum information science, that it doesn't pay to get too attached to a particular view or picture.
It shouldn't be something that becomes . . . precious to you.

Machine learning is said to be statistics on steroids. The more frequent a false information is trained to the AI model, the harder it gets to correct it later. Hence there's an incentive to feed them the correct information in the first place.

[hamdani yusuf (OP)]

p.s. ChatGPT, or Bard, is bound to contradict itself, it isn't able to understand what that is.

There's a technique called self reflection, which has been shown to significantly improve answers of AI models.

[alancalverd]

When a guitar string is plucked, it vibrates and produces a wave that travels along the string. This wave is a longitudinal wave, which means that the particles of the string move back and forth in the same direction that the wave is traveling.

Wrong, obviously. Not a good starting point for an essay.

[alancalverd]

There's a technique called self reflection, which has been shown to significantly improve answers of AI models.

However much you polish a turd, you end up with a turd.

[hamdani yusuf (OP)]

There's a technique called self reflection, which has been shown to significantly improve answers of AI models.

However much you polish a turd, you end up with a turd.

Have you read the research paper on it? It shows statistically significant improvement. What's your explanation?

[alancalverd]

My daughter-in-law is a civil engineer with an interest in sewage. I'll ask her about the statistics of turds, both raw and polished.

[paul cotter]

That's an interesting snippet of off topic information. Your good daughter in law must then be familiar with sir Joseph Bazelgette. It' a small world in terms of degrees of separation. PS I hope your ticker is behaving itself-you must feel like fish out of water with your license suspended. And Hamdani, apologies for any resultant distraction.

[alancalverd]

If you are ever in London, I can highly recommend a visit to Bazalgette's Crossness Pumping Station - amazing Victorian engineering and decorative ironwork and tiles worthy of a cathedral, being restored by brilliant and talented enthusiasts. I took a guided tour last summer beginning with a walk around City public toilets and the history of Cockney poo since the Romans, a lecture on the Great Stink (1858, not the current government) then a boat trip along the Thames to the Station and Museum of Toilets. Marvellous day out!

Interesting that Bazalgette's descendants now produce TV shows like Big Brother - they must have sh1t in their DNA!

[hamdani yusuf (OP)]

My daughter-in-law is a civil engineer with an interest in sewage. I'll ask her about the statistics of turds, both raw and polished.

Plants can turn turds into fruits.

[hamdani yusuf (OP)]

When a guitar string is plucked, it vibrates and produces a wave that travels along the string. This wave is a longitudinal wave, which means that the particles of the string move back and forth in the same direction that the wave is traveling.

Wrong, obviously. Not a good starting point for an essay.

The AI model only learned from selected curated text sources. It can't cross check with real experimental observations where it can play around with.
Perhaps the data it was trained with don't adequately explain about wave propagation on a string, which is why when I asked about it, I get an explanation about sound wave instead.