exchemist

Ah yes, theologians who are also scientists might well do, but in their capacity as scientists I presume, rather than in their capacity as theologians. Or does Polkinghorne for example employ the concept of energy in his theology?

Eh? Can you provide an example of a theologian expressing a view on "how energy functions"?

This is a Gish Gallop. There is a whole series of points and assertions here that are not connected. If you were serious about your ideas you would pick one point at a time, and follow it through rigorously in all its implications. By hurling a series of different ideas, all at once, you make it impossible to respond properly. Gish used to do this deliberately, as a rhetorical technique to make his opponents appear unable to reply coherently and thus score a "victory" in the eyes of uninformed listeners. What is the point in trying to do that here on a science forum? I will pick one easy point to respond to. A photon, or a "light ray" if you want to be classical about it, is reflected from a frosted glass surface according to the angle at which it strikes a particular point on the surface. Since the surface is not flat, that angle depends on exactly where on the surface it strikes. This explanation does not depend on whether one assumes a wave or a corpuscular model for light. I suggest you stop flailing around and focus on the photo-electric effect alone, since that is regarded as the definitive evidence for the quantisation of light. And don't get hung up on the word "particle". Light is shown to be quantised. Nobody argues it behaves like a little steel ball.

The reaction is 2H₂ + O₂ <-> 2H₂O, with a heat of combustion of 142MJ/kg of hydrogen. So for every kg you burn, you get 142megajoules (=39.4kWh) of heat out. If you want to recover the hydrogen to use again, as you propose, you have to run this reaction backwards. That's what electrolysis of water does, for example. But that requires you to put in 142MJ of energy per kg of hydrogen produced. So you get back to exactly where you started, with no net energy gain. (Conservation of energy means you cannot get something for nothing.) This is why, when people propose using hydrogen as fuel, what they envisage is using hydrogen as an energy storage medium. A cylinder of hydrogen is a lot lighter than a battery with the same energy content. But you need to make the hydrogen in the first place, which requires energy input, e.g. from renewably produced electricity, just as you do to charge up a battery. Though you can also make hydrogen by thermal cracking of natural gas: CH₄ + heat -> 2H₂ + C, in which case you get hydrogen from fossil fuel and produce a lot of solid carbon as a byproduct. This is not widely commercialised yet. I'm not sure what one does with all the carbon. I suppose one could make it into bricks as a building material, or something. The one thing you must not do with it of course is burn it!

From across the Atlantic it certainly looks like it. The thing that frightens me the most is that one of the major political parties, commanding >40% of the vote, has given up on the democratic system. To have that proportion of people being constantly told that the last election was stolen, when it quite obviously wasn't, looks like a prelude to ignoring their outcome in future. What then? Civil war? Autocracy? Yikes!

Yup, that's what I meant by the QM analogue of motion: perhaps I should have spelled out that I meant the QM representation of what would in classical physics involve motion. I realise of course there are no trajectories in QM, even though there are still properties associated with motion (e.g. momentum).

Yes. My understanding is that you need the QM analogue of periodic motion to get quantisation. So the notional "particle" is reflected repeatedly from the ends of the box, or in rotating systems, e.g molecules, it revolves repeatedly, in both cases as a result of some form of constraint on the motion. With no constraint you get a continuum without quantisation, e.g as in ionisation limits in spectra.

Atkins wasn't yet a prof when I was there. He was a fellow at one of the colleges, Lincoln, I think, where he had a bit of a reputation as a tartar to his undergraduates. But he was a charismatic lecturer, amazingly, on quantum chemistry, the most abstract and mathematical supplementary option available on the course. My maths and QM tutor told me Atkins would get really worked up and nervous before he went on to give a lecture, just like any actor before curtain up. He had a certain bone-dry wit, which he somehow managed to introduce somewhere in every lecture. But we digress.............

Re entanglement, yes, I suppose bond formation could be an example of a process by which two unentangled entities become entangled. Good one. Re absorption, I think referring to the link I posted on transition dipole moments may help. My understanding is that during the process, (speaking in crude, semiclassical terms) the electron's state becomes coupled to the electric vector and oscillates between the ground and excited states. The energy of the photon will oscillate between the photon and the electron, too. Whether this process finishes in the excited state with absorption of the photon, or in the ground state with continuation of the photon seems to be a matter of the transition probability. (If I'm remembering Peter Atkins' lectures correctly, 45 years on, which I may not be.) As I understand it (from those lectures), absorption is the limiting case of the process that that causes dispersion (in the sense of change of refractive index with frequency) at frequency ranges not too far from an absorption band. This is often described by a coupling of the electric vector of the light to the electrons in the medium, which " borrow" energy from it and give it back, altering the phase velocity of the light in the process. The dispersion of glass, for example is due to an absorption in the UV being not too far away from the frequencies of visible light. Glass with higher refractive index has a UV absorption closer to the visible than lower refractive index varieties. The light needs to be in a frequency range close enough to the absorption transition to to begin to mix the excited state into the electrons' state, temporarily, as the light passes.

I really think you need to consider more anti-psychotic treatment. I'm no doctor, but some of what you are posting seems to me to have the hallmarks of mental disturbance, e.g. the irrelevant and implausible statement about people withholding money to starve you.

That's something I didn't know. I had not been aware of any process that starts with two unentangled QM entities and then entangles them. Have you an example?

I think the problem is there are good reasons to expect such transuranic elements to be unstable and to decay fairly rapidly. So no matter how much was produced it would not last and would not be around to observe for long.

Entanglement isn't a process, it's a state.

Yeth of courthe.

No. 7.3.1 calculates line width from the lifetime of the excited state, not from the duration of the transition process. And the other example you quote is again based on working out the lifetime of the excited state, from the decay curve as the population of them decays away. This is quite distinct from the duration of the transition process, i.e. the time it takes for an electron to emit a photon and change from the excited state to the ground state. The latter is not referred to in either example. No, this notion of "leaps" became obsolete in about 1930. The process is not mysterious. It has a duration: loosely speaking, the electric vector of the photon perturbs the wave function of the electron by changing the potential it experiences, causing it to gain energy and angular momentum, absorbing the photon as it does so. This is modelled by the time-dependent version of the wave equation, though admittedly it was 45 years ago I did this stuff at university, so I may not have all the details right any more. There is a bit about it in this short description of transition dipole moments: https://en.wikipedia.org/wiki/Transition_dipole_moment And they are not "orbits" but "orbitals", the difference in nomenclature being intended to recognise that electrons do not follow fixed Newtonian orbits, but are described by "clouds" of what is more or less the square root of probability density.

The link accords with my understanding and makes no reference to the time taken for the transition to take place. So I'm afraid it sheds no light on this odd remark of Whiffen's about the duration of the transition.

There is no such thing as a "scientific burden of proof." Science deals in reproducible evidence, not in proof. The rest of your post appears to be nonsense.

A friend at work once went for a medical and returned to say, with a grin, he'd been told he was 1kg short of being "technically obese". We all thought "technically obese" was a wonderful expression.

This passage is curious as it seems to say "yes, repeat no". I can't at the moment see how if the uncertainty in energy results from the brevity, as it were, of the excited state, he can then also say it depends "in a sense" on the time the transition itself takes. Unless what he has in mind that the lifetime of the excited state is so short that the duration of the transition process is comparable with it. But that is not going to be the case in general. Does he say anything else that sheds light on this odd "in a sense" comment?

Just to clarify, my understanding has always been that it is the lifetimes of the participating states that determine the uncertainty in energy of the transition, rather than the time it takes for the transition between states to occur. So, as I understand it, states with a short lifetime have large uncertainties in energy, whereas long-lived states have small uncertainties in energy. Is that what you mean, or are you saying it is the duration of the transition process itself that is the issue? Untrue. The transition takes place within the atom or molecule that is absorbing or emitting. Uncertainty broadening is nothing to do with uncertainty as to which atom or molecule in an ensemble is going to absorb or emit. In principle it applies even to single, isolated atoms or molecules - though it would be fairly hard to measure in such a case, admittedly. You may possibly be confusing this with pressure broadening, which is another line-broadening phenomenon, due to collisions between atoms or molecules shortening the lifetimes and/or perturbing the energies of their states.

There is no distortion.

Surely if it is a square root there should be both +ve and -ve solutions, shouldn't there?

OK if you've apologised for the use of pretend I must have missed it, but fair enough.

The issue I have been disputing in this thread is the claim that a religious person has to "pretend", in some way, in order to do science. Palin, although certainly an ocean-going ignoramus, is not relevant to that. I do realise that some of the assumptions and attitudes in the thread are influenced by the US experience, in which one particular variety of redneck Protestantism seems to make all the running where perceptions of religion are concerned. The danger of that is people can end up with a completely false picture of how religions more generally, and the various denominations within them, actually regard the natural world, cf. @Markus Hanke's contribution regarding Buddhism, and what I have had to say about mainstream Christianity. (I could have added the European Lutherans and Calvinists to my list as well.) From what I can gather, biblical literalism is largely a c.19th invention, a byproduct of the Protestant sola scriptura principle, taken to excess by certain groups.

Yes of course, thanks, that makes sense. So it's a cubic relation. That would make the energy harvesting potential extremely strongly dependent on the wind strength that the device experiences in practice. So one would need to read the claims of power output very carefully with that in mind.