gib65

What's the difference between electric charge and magnetism?

The orbitals are associated with all elements. The specific values for e.g. energy, and which are occupied would be element-specific, but every element has the s orbitals, the p orbitals, etc.

Well, what I'm looking for is a chart showing which orbitals get filled with electrons based on which element you have. Hydrogen, I'm assuming, has its s-orbital filled, and then somewhere higher up the periodic table (helium? lithium?) the p-orbital gets filled.

I'm looking for a diagram that shows the shapes of different orbitals along with what element they correspond to. I've found lots of pictures of orbitals online but very few that label the type of atom (element) they're associated with. Any links would be greatly appreciated.

The situation can never happen. The closer you get to the speed of light the shorter the distance to your destination (length contraction). You will always hit the source of gravity before you reach the speed of light relative to that source.

Ah, length contraction.

What would happen to an object if it were free falling for enough time to allow its velocity to reach the speed of light. It shouldn't be able to go faster than light, right? So what happens if it has some ways left to fall?

Premise 1: 2 papers published in the same year mean they were inspired by a common source.

I never made such a statement. I said that 2 papers published in the same year might mean they were inspired by a common source. The "might" carries through to the conclusion too: Einstein might have been inspired by Planck's quantum hypothesis. Also, "inspired" doesn't have to mean "logically deduced from" - it could just mean "made him think of".

So, Planck's work still had light traveling in waves. Planck did not displace wave theory, but implied the dual nature of light: waves and particles. Now, according to your logic, wouldn't you still need an aether for the waves to travel thru?

This is actually a good point. Planck's hypothesis doesn't resurrect the corpuscular theory of light. It should be noted however, that Einstein did point out the similarities. Planck himself only proposed his hypothesis as a mathematical formality such that the formula for the energy of black body radiation would fit the data. Einstein took the next step and proposed that light really is composed of particles (later dubbed the "photon").

It was for electromagnetic systems. The wave equation would fail otherwise.

But this could work in an ether at absolute rest as well, couldn't it? Otherwise, I can't imagine why Michelson and Morly would have bothered with their experiment, expecting different time delays for their light beams to complete their journey.

This is the premise: because 2 papers were published in the same year, they were inspired by a common source.

This is not a logical deduction, it's just I guess that I feel confident about. Why else would I have put it under "speculation"?

IMO' date=' it's a pretty pointless exercise

[/quote']

 

No one's forcing you to do it.

 

gravity -- the subject of Special Relativity -- and quantum mechanics.

 

Uh... gravity is not the subject of SR - you're thinking of GR.

 

IF there were a connection' date=' then why did Einstein futilely spend the last 50 years of his life trying to unify SR and QM?[/quote']

 

I didn't say there was a connection. I just suggested that Plank's hypothesis of energy quantization resurrected a corpuscular image of light, and with that the implication that there was no need for the ether, and with that the implications of time dilation at high velocities etc.

Is there anything to the sunspot theory of global warming.

Constant c is a consequence of Maxwell's equations that took on new meaning when it was realized that light was an electromagnetic wave.

But they didn't know, at that time, that the speed of light was absolute, did they?

IIRC Einstein had stated that he was unaware of the Michelson-Morley experimental results when he published.

You may be right, but Prof. Richard Wolfson of Middlebury College says that it is unknown whether Einstein knew about the Michelson-Morly experiment or not.

The human brain wants the truth, but it also wants to keep in touch with what its community believes. If it hears X being promulgated repeatedly by its own community, it tends to lean towards accepting X as truth because it recognizes X as the accept code of the community. In other words, truth is valued, but so is staying within agreement of the community.

It's a survival tactique if you ask me. Truth is important for survival, but so is the support of one's own community, and to maintain that support, one needs to stay clear of dissension. So the brain has a natural inclination to fall into belief if it hears a common myth being spread throughout its own community. It's a way of avoiding alienation.

In researching the beginnings of quantum theory, I think I found a connection between Plank’s energy quantization hypothesis and Einstein’s theory of special relativity. It seems as though Einstein was so taken by Plank’s theory, that a whole flurry of insights were spawned in his head and subsequently published – all in 1905. Starting with the concept of energy packets that Plank proposed only as a mathematical formality, Einstein resurrected the corpuscular theory of light, and then went on to explain the photoelectric effect. Special relativity was published in the same year, which leads me to believe it was inspired by the same source – Plank’s energy quantization.

If I could get inside Einstein head, I think I would find these thoughts:

“Hmm… Light is corpuscular, after all. Well, that does away with the ether. As a wave, light would need a medium like the ether, but as a stream of particles… That puts that problem to rest, except for the Michelson-Morley experiment, and the implication that falls out of it – namely, that the speed of light is absolute. That is a quandary… but without the ether, it might work… so long as…” and the rest is history.

Maybe this is no secret. Maybe it’s common knowledge among physicists how Einstein’s train of thought linked Plank’s energy quantization to special relativity. But it isn’t to me, so I’m putting this out there for others to either confirm or show me how far out to lunch I am. Any thoughts?

Counter-question first: Why are you asking these questions and what do you need/want the answers for?

Because this sometimes happens to me when I smoke marijuana. If it's really intense, I start feeling cold. There's also the increased heart rate and retention of water, and so I sometimes get paranoid that my body is going into shock in response to these changes. I usually tell myself that it's just paranoia and I should just not worry, but it's hard to convince myself of this when I have absolutely no knowledge of physiology.

the two most important criteria for determining a shock ... are low blood pressure and increased pulse.

That sounds like an oxymoron. Doesn't an increase in pulse increase blood pressure?

I think googling for a good reliable webpage might be better than asking such questions on an internet forum.

Doing this too.

Is shivering or a sense of coldness a symptom of shock?

My question is tow-fold:

1) What are some typical stressors on the body that can cause it to go into shock?

2) What are the typical symptoms of shock?

The Bohm model doesn't offer deterministic prediction, it just postulates that such a thing might be possible, and offers a plausible theoretical explanation for how QM might be completely deterministic, with no need for "wave-particle" nonsense, either. Stuff like the double-slit experiment does not disprove it in the least, but most agree that Bell's Inequality does.

Does the Bohm Interpretation shed any light on how the pilot wave "guides" the particle? I'm just wondering how we're supposed to conceptualize the pilot wave. Does it have any "inner workings" that work out where the particle will hit the screen (or what any other of its properties will be)?

I read the wiki article and it does not say that particles have no wave-particle duality characteristics. Also, look at the criticisms against the Bohm interpretation as listed on wikipedia.

Thus' date=' in this theory all fundamental entities, such as electrons, are [i']point-like particles that occupy precisely defined regions of space at all times.[/i] When one performs a double-slit experiment (see wave-particle duality), one is concerned with noting the positions on a screen at which electrons arrive individually, one at a time. Over time, the positions at which the electrons are detected build up a pattern characteristic of wave interference. The usual Copenhagen interpretation is puzzling in that a single entity, the electron, is said to exhibit characteristics of both particle and wave. The Bohm interpretation accounts for the same phenomena by saying that both a particle and a wave do exist. The particle aspect is present because each electron traverses one slit or another, but never both. The wave aspect is present because the electron's pilot wave traverses both slits.

The italicized texts (mine) are what lead me to take the Bohm interpretation as dismissing wave/particle duality.

But that's beside the point. I'm just wondering where Bohm (or whoever suggested it) gets off saying they've done away with non-determinism.

Is anyone familiar with the Bohm Interpretation of quantum mechanics. It's the interpretation that says particles don't exhibit wave-like properties at all, that they remain point-like all along, but that there is a "pilot wave" that accompanies and guides their position and trajectory.

According to the wikipedia article, the Bohm Interpretation is deterministic - presumably because the pilot wave determines exactly the position where the particle will be found. But this seems to be somewhat of a vacuous claim. It doesn't exactly elaborate on how the pilot wave determines where the particle will be found, and thus no predictions can be made. Insofar as measuring the particle's position is concerned, the Bohm Interpretation offers no more power of prediction than the Copenhagen or any other interpretation. So why, all of a sudden, are we abandoning the idea of randomness for determinism just because there is a pilot wave distinct from the actual particle?

I don't follow that either. I think that that's the point---no one can tell what state a specific electron will be in before an experiment is done. To say that the many worlds interpretaiton is deterministic is akin to saying that you know WHICH universe (of the many) that you are living in.

 

 

 

I think that I agree. Where did you read that it was deterministic?

The wikipedia article (I know, not that great of a source). It says:

MWI allows quantum mechanics to become a realist' date=' deterministic, local theory making it more akin to classical physics (including the theory of relativity).

[/quote']

 

What about this decoherence view, that its a matter of interactions with the environment? The way the wikipedia article puts it is that a quantum system will decohere when it somehow "interacts" (not clearly defined) with something in its environment, leaving a portion of the waveform to collapse into a more classical state, and the rest to dissipate into the environment.

 

Is the state in which it decoheres still considered random? And what does it mean for the wave to "dissipate" into the environment?

I haven't followed through with this thread in a while, but I'd like to pick it up again. I'm researching the Many-World Interpretation, and I've got a question.

For those of you who might not be familiar with Everett's work (the founder of the Many-Worlds Interpretation, or the "Correlation Interpretation" as he initially called it), here is a snippet from wikipedia:

Everett's Ph.D. work provided such an alternative interpretation. Everett noted that for a composite system (for example that formed by a particle interacting with a measuring apparatus' date=' or more generally by a subject (the "observer") observing an object (the "observed" system) the statement that a subsystem (i.e. the observer or the observed) has a well-defined state is meaningless -- in modern parlance the subsystem states have become entangled -- we can only specify the state of one subsystem relative to the state of the other subsystem, i.e. the state of the observer and the observed are correlated. This led Everett to derive from the unitary, deterministic dynamics alone (i.e. without assuming wavefunction collapse) the notion of a relativity of states of one subsystem relative to another

[/quote']

 

So my question is this: It is said that the Many-Worlds Interpretation is unlike other interpretations of QM in that it is deterministic. I don't follow that. Even if the observer is correlated with the measurement he makes, there is no accounting for how that correlation was established. Why should his observations be correlated with the specific measurement he made? It seems just as random as the "collapse" of the Copenhagen Interpretation.

There's not a unique mapping, though. Like some physics calculations (especially in thermo), answers can be path dependent — it's not just a matter of where you end up, it matters how you got there. I think units is also "path dependent" and you're focusing on the endpoint and ignoring the path, as it were. The endpoint does not contain the information about how you got there.

Yeah, maybe you're right. Still, it would be nice to come up with a way of inventing abstract interpretations of the intermediate steps - as long as we always kept in mind that we were simply making something up in order to have something conceptual to hold onto. This might be a weak point, though, and I don't know if there'd be much interest in "making up ideas" by more serious practitioners - although I would still maintain that it could help novices or laymen to ease into science and mathematics more smoothly.

I don't know - might just be a pipe dream.

Next question: who discovered quantum entanglement? Or was it "discovered" at all? I mean, I can imagine that quantum entanglement is just a logical consequence of other well-known facts about particle physics. I can see the production of an electron with one value for spin and a positron with the opposite value for spin being produced by a J/psi particle being well-known already. And if spin is one of these "uncertain" variables, then gleening knowledge about the spin of one, say the electron, will give you instant knowledge of the spin of the other, leading to the EPR paradox. No experiment or accidental discovery needs to be done in order to come to this conclusion.

But I'm not sure. Was quantum entanglement discovered - or at least, officially confirmed through some kind of formal experiment - or was it just deduced from other well-known facts about quantum mechanics?

Just a few quick notes in reply here. 1) RE bolded part in your quote above: Energy and momentum are not necessarily linked. Potential energy doesn't have momentum in it, chemical energy stored in gasoline or ATP doesn't have momentum in it, the electrical energy stored in a battery doesn't have momentum in it, and yet all of these still use the same units.

 

2) Following your methodology there in your last paragraph, say I come up with a quantity that has units of mass*(length squared)/(time squared), however I got there, again how do I know if that is a unit of energy or a unit of torque? Just as was said above, two very, very different quantities, but the same unit.

 

Lastly, I am not too sure what is really wrong with the current methodology. Take F=ma, force is defined as mass times acceleration, so force is defined to have units of mass*length/(time squared). Or Work dW=F*dl, Work=force times a distance, so work has to be mass*(length squared)/(time squared). Etc., etc. The units come from the definitions of the terms, and are what they are. Again, from your way, it looks to me like putting the horse before the cart, because just because a set of units come out to a certain form, doesn't mean that that combination is meaningful.

Hmmm... all good points, but something inside me tells me that this represents a philosophical problem - not an answer. I mean, what you say makes good sense, but at the same time, all our formuli in science are said to map directly onto physical phenomena and serve as a formal expression of them. If this is true, then the same should be true for the operation each variable performs on the others, which should map onto the relations each unit bares to the others. For example, when it comes to velocity, we could say that each second is being allocated equal portions of the total distance. That is, in a *very crude* sense, time is dividing up distance among itself, and that's what "produces" the phenomenon of velocity.

This is all subject to interpretation of course, and there's actually a very good chance I'm out to lunch on this, but it's just one of those things that I can't justify yet I have a very strong sense that there has to be a meaningful relation between, not just the individual variables and the overall formuli, but each component of the formuli anyway you chop it up. Therefore, the same should be true of the units.

Obviously, this is not a scientific fact - and it's scarcely philosophy since I can't prove it... there's just that feeling.

Some unit combinations have special names and/or physical interpretation and others do not; kg-m/s are units of momentum. Others might depend on the context of how terms are defined or grouped in a formula. If you took gravitational potential energy, for example, PE = mgh, and arranged it to be PE/g = mh, you'd get units of kg-m, which would make sense if you were figuring PE for a given height on different planets (though why you'd be doing that is another question altogether)

 

Also note that a kg-m^2/s^2 is equivalent to a unit of energy or of torque, and they are conceptually different things. Units don't tell the whole story.

So, are you saying that some composite units have no meaning at all - other than how they were derived mathematically? That's a little dissappointing to me. I'd like to think that if a group of composite units are derived from a legitemate formula (i.e. it actually represents something real in the nature world), then any which way you slice it up also represents something real. For example, we know the formula for calculating kinetic energy is E=1/2mv^2. From that, we can extract mv which is the formula for momentum. Taking the units for each of those formuli, we can say that if kgxm^2/s^2 is a composite set of units for energy, then kgxm/s is a composite set of units for momentum. How this is is the question I'm asking myself. It tells us that somehow momentum is involved in the phenomenon of energy. But the only way to explain this is through the math. I'd like to derive a methodology for explaining it conceptually. I'd like to be able to explain how to make the connection between kgxm/s and momentum, and also show how that relates to the connection between kgxm^2/s^2 and kinetic energy, which itself is something that I'd like to be able to show through some kind of methodology.

I don't know if the above is clear. All I'm saying is that we've got tons of experts who can understand the math, and we also have experts, most of which are from the latter group, who understand what the individual variables (mass, distance, time, etc.) mean conceptually as well as what the formuli mean as a whole (momentum, kinetic energy, etc.), but I don't know of any experts or methodologies that can attest to the conceptual meaning any of the intermediate components of these formuli, such as kgxm or even m^2 or s^2, such that it can be shown exactly how the elementary phenomena (mass, distance, time, etc.) contribute to the composite phenomena (momentum, kinetic energy, etc.) from a conceptual perspective. It's almost as though we understand that there is a firm correspondence between the individual variables and a set of phenomena we can conceptualize (mass, distance, time, etc.), and there is an equally firm correspondence between the overall formuli and the a set of phenomena we can conceptualize for them (momentum, kinetic energy, etc.), but the road from the former to the latter relies solely on the rules of algebra - any conceptual understanding along that road has to be posponed until we get to the end.

I feel it's possible to invent a methodology to take any step in the mathematical derivation from individual variables to the overall formuli such that a conceptual model of the physical phenomena which that step represents can be uncovered. This methodology should work independently of the path one takes from the individual variables to the overal formuli - for example, from the derivation of mass, distance, and time to kinetic energy, one can either derive velocity first, square it, and then multiply by 1/2 the mass - or - square distance independently of time (which also gets squared) and then devide the former by the latter to get something other than velocity (velocity squared - which drives my point home - what on Earth is velocity squared???). I feel that if such a methodology can be put into practice, it would advance science, mathematics, and the understanding of the average layman by quantum leaps. Average people would find it so much easier to understand mathematical concepts. All too often, after inquiring into certain scientific topic - which they might genuinely be interested in - they get discourage by the load of mathematical jargon. They get lost in the numbers and symbols, and soon give up on their persuit of scientific knowledge. I feel that if such a methodology can be introduced into the school systems - probably at the university level - the reach of science would span so much more of the general population, and that would be a good thing.

Sorry - got overly passionate there... but I meant what I said .

When you have to multiply two quantities with different units together, how do you interpret the meaning of the combined units?

Take the formula for momentum, p=mv, for example - you have (say) kg times m/s. I know how to interpret m/s - for every second that passes by, so many meters are traversed. But what does kgxm mean? For every second, there are so many kilogram-meters. But what is a "kilogram-meter"?

The position and momentum probability distributions are Fourier transforms of each other (as are energy and time). The uncertainty principle falls straight out of that.

I would think so, but what does the math mean (apart from the antagonism between position and momentum)? What I'm asking is, in conveying what the math means, did Heisenberg offer an "early" interpretation, and then a "later" intepretation (either by Heisenberg again, or someone else)?