[llm_trw]

The flashlight is the radio tower, the tree is the tree, and the radio in the car is your eyes. There is no analogy here, it is literally the same EM waves shifted up to where our eyes can see them.

It's like saying that the violins is merely an analogy for how a double base works.

[JumpCrisscross]

> it is literally the same EM waves shifted up to where our eyes can see them

Rubber ducks aren't battleships because they both float. Visible light and radio attenutate in meaningfully-different ways. It's an analogy.

[almostgotcaught]

> Visible light and radio attenutate in meaningfully different ways. It's an analogy.

Lol news to me and my physics degree, Do tell because as far as I'm aware Maxwell's equations don't have an asterisk on them that say "doesn't work below 1 GHz".

[JumpCrisscross]

> as I'm aware Maxwell's equations don't have an asterisk on them that say "doesn't work below 1 GHz"

You don’t see how one being able to attenuate around a hill while another needs line of sight isn’t material to the way we use light and radio waves?

[kuhsaft]

> Do tell because as far as I'm aware Maxwell's equations don't have an asterisk on them that say "doesn't work below 1 GHz".

Did you really just pull out Maxwell's equations?

EM interacts with matter in different ways. Glass hardly attenuates visible light, but wood does. 2.4 Ghz can pass through walls better than 5Ghz.

There's the concept of permittivity wherein Maxwell's equations are defined in free space with vacuum permittivity.

https://en.wikipedia.org/wiki/Vacuum_permittivity#Permittivi...

To accurately model EM waves, you need more than just Maxwell's equations. You require material equations to model interactions of EM with media.

If you want to get really advanced, whereas Maxwell's equations are classical physics, there's Quantum electrodynamics (QED) which can model interactions of EM and matter.

https://en.wikipedia.org/wiki/Quantum_electrodynamics

[almostgotcaught]

> There's the concept of permittivity

> You require material equations to model interactions of EM with media

> Quantum electrodynamics (QED) which can model interactions of EM and matter.

It's amazing how condescending some people on here are; how could you possibly have missed literally in the first sentence of my response

> ... my physics degree

[kuhsaft]

> It's amazing how condescending some people on here are

You literally started your comment with "Lol news to me", then you used your degree as if it made you more knowledgeable than anyone else here. Take a look in the mirror?

> ... Do tell

I did?

The extra information isn't to condescend. It's for other people that want to know more about the science.

[asdefghyk]

RE "....Glass hardly attenuates visible light...." Clear glass blocks about 5% visible light

[kuhsaft]

Depends on the frequency of EM. Fiber optic communications use specific frequencies to minimize attenuation in cables.

https://en.wikipedia.org/wiki/Optical_fiber#Mechanisms_of_at...

Same with communications over coax. Obviously visible light doesn't transmit well over copper, but a spectrum of radio waves do, some better than others.

[Sesse__]

Fiber optics also uses _exceptionally_ clear glass.

If the ocean were as clear as your average long-distance fiber cable, you would see down to the bottom of the Mariana Trench (also in the range of visible light, AFAIK).

[wruza]

You could make Bob Ross a new wig from all the hairs split in this subthread.

[digitalsushi]

a lot of people here have a lot of passions, but sometimes the passions overlap and we rub shoulders. if someone had made a pokemon playing card metaphor we might be in the same general condition - but i think we're better behaved showing each other how smart we must be with radio waves instead of greymon

[acje]

Both are examples of communication by means of frequency modulated and amplitude modulated electromagnetic waves with distortion from a moving three. Also a good example that a large change in quantity is a change in kind. Probably a legit analogy imho.

[JumpCrisscross]

> Probably a legit analogy imho

It’s a terrific analogy. OP is arguing that it isn’t an analogy but an identity. For what should be obvious reasons, it isn’t. And in this case, the difference between analogy and our best model of reality is material.

[dexwiz]

Rubber ducks and battleships both displace water in the same way.

[JumpCrisscross]

> Rubber ducks and battleships both displace water in the same way

Yes. Just like light and radio waves are both EM. A rubber duck remains an analogy for the buoyancy of a battleship. Not "literally the same" thing.

[aeonik]

But if you say that a battleship floats on the water in a similar way to a rubber duck floating in the water... it's actually not similar... they are the same. It's the same water and the same physics. The "only" appreciable difference is scale.

For me, the people saying they are the literal same thing are the same type of people that gave me that "aha" moment that really helped solidify my understanding of RF.

It was pretty mind blowing when I Understood that AM is a change in brightness and FM was a change in color. We just can't see RF, but if we could, that's what it would be.

[swores]

> But if you say that a battleship floats on the water in a similar way to a rubber duck floating in the water... it's actually not similar... they are the same. It's the same water and the same physics. The "only" appreciable difference is scale.

But battleship doesn't equal floating in water, floating in water is a property it has.

If you're saying "the way a battleship floats in water is like how a rubber duck floats in water" then it's not an analogy, it's as you say just describing two versions of the same thing.

But it is an analogy to directly compare the two objects, because "floating on water" is a property of the objects it's not the object you are comparing.

Wikipedia begins its page on analogies with this, sourced from The Oxford Companion to the English Language: "Analogy is a comparison or correspondence between two things (or two groups of things) because of a third element that they are considered to share."

Or Marriam-Webster: "a comparison of two otherwise unlike things based on resemblance of a particular aspect"

Apart from rubber ducks and battleships both having the "third element", or aspect, of "primarily used for floating on water", they are definitely two completely different things. Nobody could look at a rubber duck next to a warship and say "they seem to be the same thing".

The more closely related two things are the more useful and less stretched the analogy available, which is why the analogy about radio waves was so enlightening to so many people in this thread. But it's bang on as the definition of what an analogy is.

[aksss]

Ducks and witches, on the other hand. . .

[treyd]

But RC boats and battleships both have propellers and rudders.

[swores]

It's not saying the violin IS "merely an analogy for how a double base works", just that a violin can be used as a simple analogy to somebody who understands how a violin works but doesn't know what a double bass is.

Comparing similar things is literally what an analogy is, the fact that in these two cases (radio/light and string instruments) the things being compared are very similar it doesn't make them the same thing, nor does it make it not an analogy.

[mistercow]

It is not literally the same. The colors you perceive on the screen in front of you demonstrate why. That banner above is not orange; it’s red and green. You don’t actually have the ability to distinguish a varying frequency between red-orange and yellow-orange, and two amplitude modulated “carriers” at red and green.

That’s the hallmark of an analogy. It gives the general idea, but breaks down if we interrogate it in too much detail.