Consider the lowly photon ...

<b>[Shando] "What are the ways it could lose energy?"</b>

A real physical particle can lose energy by slowing down. Or by moving closer to the center of a force field (without gaining relative speed). Or by radiating EM (or other) energy. And that is about it.

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I suppose it could also lose energy by shedding some mass. But then it becomes possible to claim it is no longer the same particle. Not sure about this one. A star does it, and we continue thinking of it as the same particle. An atomic nucleus does it, and we stop thinking of it as the same particle.

So, photons cannot be real physical particles?

We can treat EM energy, mathematically, as if it is. (Math is cool that way.) But then we have to avoid explaining the physical basis for the wave-like properties if it is not waves. Or say that it can be both. And which one it is, right now, depends on how you look at it.

And then wonder about issues like I brought up. If one photon loses some frequency now and another photon near by does not lose some frequency for several microseconds (or maybe seconds, or hours?), would we not notice?

No two photons will have exactly the same history, so such random variations among individuals must happen.

Maybe a better way to look at energy is to consider a one joule energy packet. One joule of energy is almost too small to notice in the every day world. One joule of energy can be located anywhere on the electromagnetic spectrum. If we put the packet at a frequency of ~10E11hz it will warm a very tiny mass a very little. If placed at ~10E14hz it will light a small area for a second. If placed at 10E20hz it will kill a horse. That is a result of force as the energy never changes. The packet of energy has force related to the frequency and that force causes different effects related to frequency.

I think I have found my problem: I didn't understand that when you start talking about the waviness of light, you stop thinking about photons. Photons only apply to light as particles.

I was thinking that a photon could consist of a "wavelet" with a beginning and an end, consisting of a finite number of cycles. I was led to this idea by the concept that a photon is a quantum of energy, proportional to, if not equal to, hf (plancks constant times frequency). If a particle isn't a wave how does it have a frequency?

It is a good question. Since the experts do not agree with each other, we do not really have a good answer. But we do have answers. We always have answers. And sometimes that is a serious problem.

Waves have properties like frequency, amplitude and the INability to collide with each other.
Particles have properties like mass, size and the ability to collide with each other.
Waves do not have mass and particles do not have frequency. Or do they?

Light is said to have some properties from both lists. Frequency of course. But it also seems to have an energy "size". This is not the same as a physical size, which is a particle property that the photon does NOT have.

Some "known to be particle" objects, such as the proton, also have a property or two know to be associated with waves. Usually referred to as the 'quantum mechanical wave nature' of the proton.

But the particle properties of light and the wave properties of particles are typically not defined or identified with as much clarity and certainty as was the case in the days of classical physics. This does not make the "new fangled" things wrong. But it can make them confusing. And it strongly suggests that at least some of what we know about these little tiny parts of nature is at least partly wrong.

The possibility that we have made no incorrect interpretations of the data we have collected over the decades is fairly small. We can't see the little dudes, so we have to study them indirectly. We can isolate them as individuals, but it is difficult and expensive so often we study a lot of them at once and make assumptions from that data which we then apply to individuals. And it works. Most of the time.

Some people 'solve' this confusion problem by using the word photon to mean a "group" or "collection" of waves. Tom was sort of into this idea. I prefer to think of light as waves when I am looking at wave properites, and as particles when I am looking at particle properties.

Of course, if it turns out that there actually is an LCM the particle idea goes out the window. Or if it turns out that there actually is not an LCM the wave idea goes bye bye.

So when will we know who is right? Probably not until we develop technology that allows us to detect things much smaller than we can right now.

Thanks LB, I shall sleep better tonight.

Larry,
I have developed a lot of perspectives by assuming light and EM radiation travel as beams with waves. I dont see any reason they should travel as particles. It is said that light has zero mass in motion. It is upon impoact that motion ceases and any particle nature would occur. That there is impact may suggest particle nature, however a wave will 'splash' down with slight impact since waves have altitude. Only a waveless beam will contact a mass without creating this minor level of impact. In that case the beam will penetrate the mass.

Beyond this I never understood the measurement given to photons. It doesnt seem to relate to wave length in any way.

Paul Schroeder

paul schroeder