How is that momentum transferred? When a marble rolls past a stationary one, the stationary one doesn't just start moving. Do the charges have little sticks that the prod each other with?
How does that current and potential get into the middle capacitor? And what what is current times potential, if it isn't energy?
which explains clearly that it is a theory dictating where energy flows, not experiments.
Much like bsfeechannel, they don't point to experiments, because they cannot.
Mmh I'm not quite sure why you renamed potential energy into 'backpack', but if I were to explain electricity to children, I would consider it. Ispotentiala forbidden word now?
I'm curious how you see energy moving in vacuum. Is vacuum filling/emptying backpacks too? And giving to electrons/protons?
As mentioned above electrons will repel other electrons (force will drop with distance) So this repulsion force works across a fairly large gap like the dielectric in a capacitor or even 1m in air.
But it's not particularly important where and how it goes.
As mentioned above electrons will repel other electrons (force will drop with distance) So this repulsion force works across a fairly large gap like the dielectric in a capacitor or even 1m in air.
If that is so, then that's a big problem.
...
(once again this all ignore the magnetic field, which is actually needed to receive signals from Mars...)
How is that momentum transferred? When a marble rolls past a stationary one, the stationary one doesn't just start moving. Do the charges have little sticks that the prod each other with?
How does that current and potential get into the middle capacitor? And what what is current times potential, if it isn't energy?
For electrostatics, the electric field fill the universe (just like gravity does). And the location of charges in that field define the electric field, just like how the location of masses define the gravitational field.
In a wire, where charges can move freely, changes drift to where they see the local field leading them, like marbles rolling down into a valley under gravity. They don't need to 'know' that there is a battery that is 10cm away to know which way to go, they just mindlessly follow the slope of the local electric field. Exactly like how water finds it's way to the outlet of a lake or dam. And as they move, their location also contributes to the electric field. Because charges are able to freely move within the wire, and their location defines the electric field, the electric field quickly becomes flat inside conductors when modest currents are flowing. The charges are not dissipating much energy, they are "doing minimal work" in the physics sense (force x distance).
At the edges and outside of the wires, where the charges can't freely move is where all the tension in the electric field occurs - that is where the fields have the most 'slope'. It is on that slope where you can extract energy from the fields. If you release a charge on such a slope it will know which way want to go - a negative charge will head in the "most positive" direction, and a positive charge will head in the "most negative" direction. If you were able to put an extra charge into a wire not much will happen - it will just drift along on the current.
You attach one end of a resistor to a just the positive wire, but leave the other end free. A small amount of charge will flow into it, but very quickly the whole resistor will have an flat electric field, just as flat as the wire. Anywhere you measure with a voltmeter on the either resistor or the wire will measure 0V. The resistor isn't releasing any of the field's energy, just moving where the field's energy is in space.
But when you attach one end of the resistor to a positive wire. and the other end to the negative wire, then you can extract energy from the field. All the semi-mobile charges in the resistor will see the "so many volts per meter" slope of the field and start moving in that direction. Those charges don't need to know how the electric field gets there, just that the field is there, and it has to follow it. This converts electrical energy into momentum of the charge.
Because the slope in the resistor is so high compared to that inside the wire, they really want to move fast. This gives the thermal heating (or light from the light bulb). That energy isn't coming from the electrons moving in the wire, but the slope in the electric field that is through the resistor, that is what accelerates the charge.
The wire supplies a steady supply of low-energy electrons to be accelerated in the resistor, and removes the low energy electrons that appear at the resistor's other end. The charge is accelerated using the energy supplied by the field, not the wire.
All this time, (assuming resistance of the wires is low compared to the resistor the wires) the electric field on the inside of the wires is flat, and the charges in the wire only transfers minimal energy. The wires set the shape of the electric field, and supplies charge, but the energy flows in the fields.
Batteries also change the shape of the electric field. They generate (and try to maintain) an electric field between their terminals. Batteries are sold as X volt batteries. The first thing you care about for a battery is the strength of the electric field it generates between its terminals. The total energy it can supply is a secondary consideration (along with size or cost). When you connect a battery to a wire, because the wire's charges are mobile the electric field around that wire changes to match that of the battery's terminal. And sure, some charge movement is required for this, but if you could look at how much charge moved how far to build up the electric field it is minimal. (That is unless somebody has put a large capacitor in there somewhere...)
which explains clearly that it is a theory dictating where energy flows, not experiments.
Much like bsfeechannel, they don't point to experiments, because they cannot.
It's theory explaining experiments. That's what a theory is for. I told you several pages ago that the idea that energy was transmitted in wires was already debunked in the 19th century based on experimental data. I even described what experiments they were.
Mmh I'm not quite sure why you renamed potential energy into 'backpack', but if I were to explain electricity to children, I would consider it. Ispotentiala forbidden word now?
I'm curious how you see energy moving in vacuum. Is vacuum filling/emptying backpacks too? And giving to electrons/protons?
What is remarkable of Derek's experiment is that it tosses in the bin all the alternatives to the Poynting theorem--a kind of discussion that only entertain physicists--especially S=VJ, so cherished by the hydraulic analogy lovers.
The real issue with this thread and others like it, is that the wrong language is being used to discuss the topic under consideration--a natural language, like English.
Such language is too imprecise, and subject to too much misinterpretation.
To be successful, the language used needs instead to be mathematical, such as shown in this video:
(The video even comes with an accidental mistake as a bonus!)
A photon is the elementary particle dual of an electromagnetic wave. Light is an electromagnetic wave.
A photon is the elementary particle dual of an electromagnetic wave. Light is an electromagnetic wave.A photon is the fundamental (quasi) particle.
Photons emit em radiation, from the main central helical body of the photon.
Radio waves are em radiation.
EM radiation is a slab of E by H energy current. When i say slab, i mean there is no rolling E to H to E etc. Hertz was wrong.
A photon is the elementary particle dual of an electromagnetic wave. Light is an electromagnetic wave.A photon is the fundamental (quasi) particle.
Photons emit em radiation, from the main central helical body of the photon.
Radio waves are em radiation.
EM radiation is a slab of E by H energy current. When i say slab, i mean there is no rolling E to H to E etc. Hertz was wrong.Radio waves, as first demonstrated by Hertz, are macroscopic phenomena.
Photons are microscopic.
The standard derivations of E and H in the "far field" (radiation region) have been demonstrated in RF engineering over and over, to the point that they are no longer discussed. It works.
In passing from the microscopic quantum domain to the macroscopic classical domain (such as Maxwell), the macroscopic quantities are the "expectation values" (q.v.) of the quantum mechanical description.
Fourier analysis shows that any periodic waveform can be represented as a series of sinusoidal waveforms, or an integral over a continuous frequency range of sinusoids.
When building a transmitter, you will find that a sinusoidal carrier is a useful and efficient generator of radio waves.
Even Marconi's evanescent waves from ratty spark waveforms contained a sinusoidal carrier, due to the resonance of the antenna system.
Sounds mostly correct to me. But I don't see how electrons are shoved by the electric field, with a stick perhaps? And how do they 'see' it, with tiny eyes?
"I am not sure how Hertz got a sinusoidal shape from his ordinary spark."
This is the same method Marconi used, exciting a resonant circuit (in Hertz' case, a "Hertzian dipole" resonant antenna) to generate an evanescent waveform: a sine wave multiplied by a decaying exponential (as the circuit loss dissipates energy from the resonant circuit). I believe the first practical transmitter to generate a true "continuous wave" was the Poulsen arc, later improved into the "Federal Arc", where a carbon arc's negative resistance placed across a resonant circuit. Later, Alexandersson built a 200 kHz high-power alternator for GE. Both were made obsolete by the vacuum tube.
https://farside.ph.utexas.edu/teaching/em/lectures/node94.html for the math behind the Hertzian dipole.
See my reply no. 362 above.
Interesting.
Anyhow, if Hertz intentionally or accidentally made a sinusoidal radio wave, then what reasoning was used by everyone to say that a radio wave is a photon(s).
Radio waves, as first demonstrated by Hertz, are macroscopic phenomena.
Photons are microscopic.
The standard derivations of E and H in the "far field" (radiation region) have been demonstrated in RF engineering over and over, to the point that they are no longer discussed. It works.
In passing from the microscopic quantum domain to the macroscopic classical domain (such as Maxwell), the macroscopic quantities are the "expectation values" (q.v.) of the quantum mechanical description.
See my reply no. 362 above.QuoteInteresting.
Anyhow, if Hertz intentionally or accidentally made a sinusoidal radio wave, then what reasoning was used by everyone to say that a radio wave is a photon(s).Radio waves, as first demonstrated by Hertz, are macroscopic phenomena.
Photons are microscopic.
The standard derivations of E and H in the "far field" (radiation region) have been demonstrated in RF engineering over and over, to the point that they are no longer discussed. It works.
In passing from the microscopic quantum domain to the macroscopic classical domain (such as Maxwell), the macroscopic quantities are the "expectation values" (q.v.) of the quantum mechanical description.
How kum a microscopic photon can be mistaken for a macroscopic em something.
In physics, statistical mechanics is a mathematical framework that applies statistical methods and probability theory to large assemblies of microscopic entities. It does not assume or postulate any natural laws, but explains the macroscopic behavior of nature from the behavior of such ensembles.
Interesting.
Anyhow, if Hertz intentionally or accidentally made a sinusoidal radio wave, then what reasoning was used by everyone to say that a radio wave is a photon(s).
See my reply no. 362 above.
Radio waves, as first demonstrated by Hertz, are macroscopic phenomena.
Photons are microscopic.
The standard derivations of E and H in the "far field" (radiation region) have been demonstrated in RF engineering over and over, to the point that they are no longer discussed. It works.
In passing from the microscopic quantum domain to the macroscopic classical domain (such as Maxwell), the macroscopic quantities are the "expectation values" (q.v.) of the quantum mechanical description.
How kum a microscopic photon can be mistaken for a macroscopic em something.
A whole bunch of them make a macroscopic wave. Many a pickle makes a muckle. In formal language, an ensemble.