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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
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IanB:

--- Quote from: TimFox on May 12, 2022, 02:56:13 am ---I have seen photons reflect from surfaces (dead ends) when doing photography.

--- End quote ---

I was struck by the observation that the coating on a camera lens is in fact a quarter-wave impedance matching transformer (it prevents unwanted reflections off the lens surfaces).
aetherist:

--- Quote from: TimFox on May 12, 2022, 02:56:13 am ---I have seen photons reflect from surfaces (dead ends) when doing photography.
--- End quote ---
Yes free photons can indeed reflect from a deadend, ie a photon inside a glass prism can reflect off the end of the glass, ie some do reflect while some don’t (in which case they exit the prism).
Internal reflexion has i think a different cause to external reflexion.
However, i have trouble re how some light can be reflected internally when the incidence is exactly perpendicular (i think this angle is called 00 deg).
External reflexion for 00 deg is i think explainable, but internal reflexion is a worry (for my theory).
The standard explanation for IR involves i think absorption of the photon, & re-emission.  I am sceptical that absorption is the answer.
Anyhow a free photon (an eagle) is a slightly different bird to an elekton (an emu).
Free photon reflexion is i think different to elekton reflexion.  In fact i don’t think that elektons can reflect at all.

I should not call a photon in glass a free photon, but i call it a free photon koz free photons propagate in a straight line, & a photon in glass propagates in a straight line, even tho it is constrained rather than free, ie it is slowed due to drag from the presence of mass (glass), but that drag is evenly distributed all round. I should have called it a gannet or duck rather than an eagle. The photon is sometimes a flying duck (ie a free photon) or a swimming duck (elekton) or a diving duck (no name), or a duck that has bitten its own tail (free electron), or a duck that is orbiting a nucleus (orbiting elektron).

The 6th kind of photon is the neutrino, this is 2 photons that have merged by virtue of sharing their axis (ie photons have a helical main body, with an axis), the 2 photons sitting a half cycle apart, in which case their em fields cancel in the nearfield, in which case a neutrino is very slippery (compared to an ordinary single photon which has a non-zero em field in the nearfield).

https://en.wikipedia.org/wiki/Total_internal_reflection
U might notice that in relation to reflexion wiki mentions an evanescent wave going parallel to the surface of glass.
My elekton is an evanescent photon going parallel to a wire.
Berni:
Signal reflection is not electrons bouncing back from the end of a wire like a ball bounces off a wall.

It is more like how waves on the surface of water bounce back from a wall. The magnetic field around the wire keeps pushing electrons along, but once they hit a dead end on the wire they bunch up closer together (this effect is very tiny since packing them only slightly closer massively increases the number of electrons and quickly builds up the required voltage to resist it). At some point they bunch up enough to create enough backwards pressure due to the voltage build up that the magnetic field is reduced down to 0. Yet at this point the electrons are still bunched up creating voltage, so they shove electrons back out of that dead end, creating current and a accompanying magnetic field that then drives the reflected wave back from where it came from.

The voltage and current (or electric and magnetic field) can be thought much like surface height and horizontal velocity in water waves. One affects the other causing them to travel around and interact in all the usual ways. The wave is what travels, not the particles themselves.

The one big difference between water flowing trough pipes and electrons flowing trough wires is that they get there "momentum" mostly from the magnetic field rather than the mass of the particle itself. The electrons move very little in wires and they have very little mass. However this magnetic field is not local to just that one electron, same for the electric field created around the electron. So as a result they can affect other electrons over a significant distance. This is what makes transmission lines act the way they do, also what makes it different than water flowing trough pipes.
SilverSolder:

--- Quote from: aetherist on May 12, 2022, 07:09:59 am ---
--- Quote from: TimFox on May 12, 2022, 02:56:13 am ---I have seen photons reflect from surfaces (dead ends) when doing photography.
--- End quote ---
Yes free photons can indeed reflect from a deadend, ie a photon inside a glass prism can reflect off the end of the glass, ie some do reflect while some don’t (in which case they exit the prism).
Internal reflexion has i think a different cause to external reflexion.
However, i have trouble re how some light can be reflected internally when the incidence is exactly perpendicular (i think this angle is called 00 deg).
External reflexion for 00 deg is i think explainable, but internal reflexion is a worry (for my theory).
The standard explanation for IR involves i think absorption of the photon, & re-emission.  I am sceptical that absorption is the answer.
Anyhow a free photon (an eagle) is a slightly different bird to an electon (an emu).
Free photon reflexion is i think different to electon reflexion.  In fact i don’t think that electons can reflect at all.

I should not call a photon in glass a free photon, but i call it a free photon koz free photons propagate in a straight line, & a photon in glass propagates in a straight line, even tho it is constrained rather than free, ie it is slowed due to drag from the presence of mass (glass), but that drag is evenly distributed all round. I should have called it a gannet or duck rather than an eagle. The photon is sometimes a flying duck (ie a free photon) or a swimming duck (electon) or a diving duck (no name), or a duck that has bitten its own tail (free electron), or a duck that is orbiting a nucleus (orbiting electron).

The 6th kind of photon is the neutrino, this is 2 photons that have merged by virtue of sharing their axis (ie photons have a helical main body, with an axis), the 2 photons sitting a half cycle apart, in which case their em fields cancel in the nearfield, in which case a neutrino is very slippery (compared to an ordinary single photon which has a non-zero em field in the nearfield).

https://en.wikipedia.org/wiki/Total_internal_reflection
U might notice that in relation to reflexion wiki mentions an evanescent wave going parallel to the surface of glass.
My electon is an evanescent photon going parallel to a wire.

--- End quote ---

There is always going to be some diffusion, however miniscule it may be...   - in the real world, we don't have perfect reflectors?
penfold:

--- Quote from: adx on May 11, 2022, 08:13:47 am ---
--- Quote from: penfold on May 10, 2022, 09:45:27 am ---..
Anyway, interesting point you (adx) made previously about the hydraulic analogy... I did wonder, much earlier on, whether Derek was simply setting us up for a video entitled "The big misconception about hydraulics". Extending the "rubber hoses in air" (the hoses being somewhat compliant and able to transmit a pressure wave), I wondered what would happen if the hydraulic circuit were constructed, rather than with tube in air, with cavities, channels, or tunnels within a soft and gelatinous medium (low-durometer silicone rubber perhaps). [...]

--- End quote ---

That's certainly an interesting thought. I was trying to work out how a fluid analogy of a transformer would work some time back, and worked something out based on sort of similar principles - but hadn't thought of making a hydraulic circuit with "radiation". My mind boggles at the opportunities (none of them business!). Little embedded air bubbles to visualise it? Would mercury be too heavy? Advertising opportunities on YouTube maybe (as SiliconeAether?), high speed cameras, sounds like a fun thing to do.

--- End quote ---

Yeah... the fluid transformer analogy has me stumped a little bit, at least I just can't imagine it quite. A capacitor could easily work like a bladder pump (used in groundwater and deep bore-hole sampling) and I'm imagining some transmission line coupling similar to a peristaltic pump due to a wave of pressure fluctuations, giving some transmission line characteristics. With a jelly-like medium, I like the way it separates the E-field-like and H-field-like components (we can have a permanent displacement, but no continuous velocity)... but can't quite think of a good H-field equivalent, possibly on a geological timeframe with lava flows or shorter times in weather systems... time to revise some fluid dynamics.

Mercury could be a good fluid to use... in small quantities, I'm sure it wouldn't sink through gelatine, and being conductive it would be easy to measure spikes in pressure from it jumping up in risers/vents at strategic points. But... yeah... it's utterly useless I guess, maybe it's a good analogy of a non-real view of electricity without DC magnetism, otherwise, just food for thought (though... maybe hold the mercury in the jelly).

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