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I've been building an AM transmitter and it's generated a lot of questions. At the top is the electromagnetic wave. It may seem simple but I've yet to find an answer. As far as I know, light is made up of photons generated when any charge particle accelerates. When people refer to photons as particles, I think of them as more of a solid object so to speak. How do they wave and have wavelengths? The small photon isn't being stretched out or moving up and down potentially miles across. To the best of my knowledge, it's an emergent phenomenon. For example, water molecules don't wave but together you see higher and lower concentrations of molecules that appear to us like waves in even spots. Or is it something different like photons being generated on different points on the antenna? As the electric charge goes across the wire, each point a photon is being generated. The wave would emerge as the photons are jumping off at different points? The only other thing I could look into is quantum theory. One form suggested that was the only way to understand light. At that point, I feel like it's black magic and boogeyman.

What's happening? I never understood the particle-wave duality. The more I look for the truth, the more I realize we don't fully understand it. When I looked down the rabbit hole, the only answer I got was that all the theories we have are just approximations of something deeper. Maybe that's why it's never made sense to me. I don't have a math background so it would be nice to have a simple answer. What is the wave and where does it come from?

Edit: I'm editing this to make my question more clear. basically I don't fully understand light even from all the materials I read online and in books. My basic question is what is the wave? All my rambling above is to try to throw out some theories that make sense in my head. Light exists and is physically real. I was on the Ham radio forums and they suggested I post in here. I'm trying to understand my AM radio antenna more. I wish I could see so to speak the wave peel off from the metal antenna. If you were to blow it up or see it in slow motion. It's a real thing. What does the wave look like? Is it spatial? My question is what is the wave?

All these models just kind of poke around the bush with extreme math. If I were to shrink myself down what would it look like and does it have any dimensions?

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    \$\begingroup\$ The electromagnetic field is waving. \$\endgroup\$
    – Hearth
    Dec 22, 2020 at 2:31
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    \$\begingroup\$ You can think photons or you can think waves. It is best not to think both at the same time. If you are thinking about electromagnetic waves in free space, then there is actually nothing waving (no matter is waving). At any point, in the path of the wave, if you stand still, then you will see a sinusoidal electric field and a sinusoidal magnetic field. I mean that the field is sinusoidal in time. \$\endgroup\$
    – user57037
    Dec 22, 2020 at 2:32
  • \$\begingroup\$ Photons travel in straight lines at the speed of light. Well, actually gravity does pull them off of their perfect straight line path. But this is a small effect normally. When a photon encounters matter, it may be refracted as it travels through the matter. \$\endgroup\$
    – user57037
    Dec 22, 2020 at 2:34
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    \$\begingroup\$ While this is an interesting question, I don't think it is an electrical engineering question. \$\endgroup\$ Dec 22, 2020 at 2:43
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    \$\begingroup\$ Photons do not have "position" as an observable. So it's probably better not to ever think of them as particles. You can get away with the particle idea for special cases. But it's probably better to think of them as spatially extended fields as a function of space-time (neither of those can be taken in isolation) that may interact with an antenna, transferring one or more quanta of energy to the antenna. \$\endgroup\$
    – jonk
    Dec 22, 2020 at 2:44

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Actually, it is not known and it's where the limits of our understanding of physics currently lies (as to show how little we know).

As the Wave-Particule Duality:

Although the use of the wave-particle duality has worked well in physics, the meaning or interpretation has not been satisfactorily resolved.

It seems as though we must use sometimes the one theory and sometimes the other, while at times we may use either. We are faced with a new kind of difficulty. We have two contradictory pictures of reality; separately neither of them fully explains the phenomena of light, but together they do.

You are entering quantum physics, where stuff is really weird. The current most prevalent theory is the Schrodinger (and many others) one with the principle of the observer:

  • As long as the particle is not observed, it behaves as a statistical wave, and as soon as it is observed it becomes a particle with a location.

It is outlined by the famous Schrodinger cat.

This is also outlined by the double split experiment, aka the "experiment that breaks physics".

Because it demonstrates the fundamental limitation of the ability of the observer to predict experimental results, Richard Feynman called it "a phenomenon which is impossible […] to explain in any classical way, and which has in it the heart of quantum mechanics. In reality, it contains the only mystery [of quantum mechanics].

It is confusing and debatable as to what "an observer" actually is and this is where entanglement takes place, is an observer being entangled with the particle? The many-world theory suggests that.

There are many different theories and it is a deep rabbit hole that cannot really be summarized in an answer here. There are a lot of resources on the internet.

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  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – Voltage Spike
    Dec 22, 2020 at 14:33
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As far as I know light is made up of photons generated when any charge particle accelerates. When people refer to photons as particles, I think of them as more of a solid object so to speak.

This is very wrong. Photons are not objects, they are the units of energy contained in an electromagnetic field. For example, a field contains 0, 1, 2, or ... photons worth of energy. For a radio broadcast, each photon of energy is so small it's practically small enough that it can be ignored and the field treated as an analog variable. For shorter wavelengths the photon energy can be large enough that it's measurable, in which case we say that the field has particle-like properties. In either case though the field is the thing that exists, not a bunch of imaginary balls being thrown at you.

How do they wave and have wavelengths?

They don't. An electric field oscillates, which creates an oscillating magnetic field, which creates an oscillating electric field, and so. This field contains energy, whose units are in photons.

I wish I could see so to speak the wave peel off from the metal antenna. If you were to blow it up or see it in slow motion. It's a real thing. What does the wave look like?

You can solve for the actual electric (or magnetic) field amplitudes of simple antenna and then render them. Some random examples of antenna fields on Youtube (selected purely based on visuals):

https://www.youtube.com/watch?v=UOVwjKi4B6Y

https://www.youtube.com/watch?v=hfkTNbT9WjM

But basically, they look like you would expect. The field oscillates as the excitation spreads outward from the antenna, with the spatial distribution reflecting the gain of the specific antenna configuration.

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  • \$\begingroup\$ So you're saying the field exists? Is it this invisible 3D field we are walking through? Like a swimming through water we can't feel or see? Problem with that is light behaves like a particle too. It's not really a wave either. So the field theory doesn't make sense to me. \$\endgroup\$
    – Derpy
    Dec 23, 2020 at 1:54
  • \$\begingroup\$ @Derpy You're doubting that the electric and magnetic fields exist? Have you used an electrical device? Stuck something to a magnet? Shouldn't take you long with either to convince yourself they are very real. "Light behaves as a particle" -> see first paragraph above for what that means. \$\endgroup\$ Dec 23, 2020 at 1:57
  • \$\begingroup\$ Do they exist? Richard Feynman had a talk with someone and questioned everything. It kind of clicked for me. At least that we know we don't know. A few science videos explain to me that they don't exist. We just pretend they do. It's just a model. I could probably link you the video. \$\endgroup\$
    – Derpy
    Dec 23, 2020 at 2:04
  • \$\begingroup\$ So if the fields exist then my next question would be what is the field made out of? What's in between charged particles? My understanding is this just a model to explain the attraction of particles. A couple of reputable science videos I've been watching say they really don't know \$\endgroup\$
    – Derpy
    Dec 23, 2020 at 2:06
  • \$\begingroup\$ @Derpy I think broader philosophical questions about what it means to be real are off topic here. From an (on topic) engineering perspective they do exist because you can use and manipulate them (e.g. go pick up a magnet and some iron filings). If you want to know the underlying physics of how fields propagate through space you'll need to read up on quantum electrodynamics and linear algebra. \$\endgroup\$ Dec 23, 2020 at 2:14
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A basic problem with your question is the embedded assumption that simple answers regarding certain properties of the universe exist, or exist in some form comprehendible to human brains without (or even with) a math background.

At least one physicist said something like "stop talking and just calculate" (the probabilities).

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  • \$\begingroup\$ It's a real object and it exists. It lives in space. It's a real thing. So it must only have one answer. Looking at math seems backwards. I don't need to know the velocity of an unladen swallow to understand what it does and is. I feel like it should come after. It's just a way to calculate something we understand. \$\endgroup\$
    – Derpy
    Dec 23, 2020 at 1:59
  • \$\begingroup\$ At the very least thank you for your help. It gets me closer to understanding what the wave actually is. \$\endgroup\$
    – Derpy
    Dec 23, 2020 at 3:34
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As far as I know light is made up of photons generated when any charge particle accelerates. When people refer to photons as particles, I think of them as more of a solid object so to speak.

That's not how you should think of them. It may help to think of light as something other than either a particle or a wave - and unless you're willing to address your math shortcomings, you'd better leave it at that. Just keep in mind that how you want to interact with/measure light determines whether or not it makes more sense to treat it as a wave or a particle. Each is a model for how light interacts with the universe, and as the old saying goes, "All models are wrong. Some are useful."

How do they wave and have wavelengths?

When dealing with light as photons, you need to keep a few things in mind. First and foremost, they aren't little bullets or ping-pong balls. If you must think of them that way, they are fuzzy particles, whose locations are only describable in terms of probability. Not only that, but they are "aware" of the behavior of other photons. Photons are "particle-like" only when you measure the energy which is transferred to whatever detector is being used, and in that sense thinking of a localized impact can be very useful. But in general, when you take a large number of these impacts into account, they behave as if their probability of happening duplicates what would happen if they were waves.

The simplest answer to this question is, "Because quantum." In some circumstances that's an expression of ridicule, indicating that the speaker doesn't know what he or she is talking about and is desperately trying to hide the fact. In this case, it's the literal truth. Once you get down to very fine scales, the universe gets irredeemably weird by the standards of regular experience, and you'll just have to accept that fact.

To put it another way, photons don't wave and don't have wavelengths - except when it is convenient to treat them as if they do.

I'm sure that none of this makes sense, as it goes against all the intuitions and common sense which you have developed in living your life. If you want to have a go at understanding photon/wave duality, you are going to have to accept that, for very small scales, everything you know is wrong. Some of the time.

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