Talk:Coriolis effect

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CORIOLIS EFFECT: AN INTELLECTUAL ILLUSION[edit]

AN INTELLECTUAL ILLUSION The alleged Coriolis "effect" is nothing more than the statement of the obvious. If you want to hit a moving target you have to aim where it is going to be when the bullet arrives at the target. Beyond that the article is nothing more, I am sorry to say, than an illusion of being correct. Not unlike for 1500 years the "learned centers of the world" insisted that all the stars rotated around the earth. And both suffer from the same mental illusion and logical mistake.

That is....they take a "human, LIMITED VISUAL PERCEPTION" that is, MOST OFTEN, different than the true complete picture of a reality environment and treat it as having some meaningful effect:

In the rotation of the stars illusion,they placed meaning on the "false" human visual perception that the stars were moving from one side of their limited field of vision, to the other side...that therefore it was a factual reality that the stars were moving in the direction of their perceived motion.

Illusions are based on the assumption that my limited point of view....is conveying to me ALL THE RELEVANT INFORMATION TO MAKE A DECISION ON WHAT THE TRUE REALITY IS. Magicians make use of our willingness to make this kind of unwaranted assumption all the time.

In the star case, however, we fail to take into account, because it is not also readily apparent, that in fact...we are also moving because we are standing on the earth which is revolving. When we do, we quickly come up with the correct description of reality.

In the present intellectual Coriolis exercise...you will note that it does the exact same thing. In fact, it actually acknowledges that that the peceived motion is a false one. The ball actually travels in a straight line, not the curved one we visual percieve under the unique circumstances arbitrarily imposed on our point of view. But, then the theory goes on to TOTALLY IGNORE THE REALITY just stated that we are perceving something that does not exist.

The Coriolis perception then is switched, BY HUMAN INTELLECTUAL THOUGHT, to an ACTUAL CORIOLIS FORCE THAT CHANGES THINGS in accordance with the characteristics of the FALSE HUMAN PERCEPTION first descibed. But, whether it is the balls thrown over the rotating table.....or what air molecules do in the atmosphere as part of a high or low pressure pattern or the stars....they are not aware of our false visual perspective, could care less about it and which has absolutely NO EFFECT ON WHAT THEY DO.

Unfortunately, the acceptance of the Coriolis "visual effect" as a legitimate explaination has stopped any further human effort to search for and explain correctly several things, including the REAL REALITY REASON and very important reason why the atmosphere rotates around high and low pressure areas AND why the rotation is the opposite in the northern and southern hemispheres.

But what is amazing and useful is....once one realizes that the Coriolis ILLUSION does not explain anything except the obvious....and you start searching again....the real answer is as simple and obvious as the true reality: that it is the earth's revolution on its axis that causes our "false visual perception" and in fact the stars, while they have their own motion to deal with....do not rotate around the earth.

But since this forum's rules do not allow original research....I'll leave it at that, except to say that I now have had 75 years of experience with reality including having obtained a PhD level certificate from these "learned centers; and it would be a mistake, I think, to make the assumption that, in the learned centers of the world, these kinds of "universal acceptance" of many basic premises as correct when they are as "obviously false as Coriolis " are a rare occurance or that they only happened a thousand years ago. Rowland2 (talk) 20:02, 23 March 2012 (UTC)

Perhaps you should re-read the article. The Coriolis force is described as a fictitious force, inertial force, or pseudo-force, essentially for the reasons you state. It does not exist when measurements are made in an inertial frame. It is however a very useful mathematical convenience when working in a rotating frame, such as that of the Earth. It is no doubt possible to calculate the motion of winds and weather systems in a non-rotating reference frame but this would extraordinarily difficult. It is much easy to pretend the Earth's surface is an inertial frame and add the two fictitious forces necessary to make the physics work. Martin Hogbin (talk) 10:14, 24 March 2012 (UTC)
The article is good, and Martin, you are right regarding the description of the force as a fictitious force... ecept in the introduction (second paragraph, I think?). The problem arises because the use of the term "force" depends on the discipline: in Physics (my field), it never is mentioned as a force at all; however, in Engineering, it is useful to treat is as so (same as the centripedal and centrifugal ones). The introduction should be modified so that the definition of the Coriolis effect as a pseudoforce is introduced before treating it as a force - both acceptions are acceptable, but the way it is currently written is not clear enough. Just an opinion, though...::Jordissim (talk) 03:03, 23 May 2012 (UTC)
What's an example of a fictitious centripetal force? —Tamfang (talk) 04:07, 23 May 2012 (UTC)
For one, forces called as such in orbiting movements: they are but (very appropiate) Newtonian approaches to general realtivity solutions dealing with bodies moving in geodesics within gravity wells. Jordissim (talk) 23:22, 28 May 2012 (UTC)
Feel free to clutter up your own writing with unnecessary <br> tags, but please don't add them to mine. —Tamfang (talk) 23:53, 28 May 2012 (UTC)
I sincerely don't understand what's going on here. I sent you a message stating clearly that I didn't want any animosity between two fellow contributors, and least of all with someone I will most certainly cross paths with in the future - yet I'm paid with a polite yet (in my opinion) inappropiate answer. I really would appreciate you telling me why a misplaced <br> tag in a personal Talk page should annoy you at all (I'm pretty new to Wikipedia, and bound to make format mistakes - as anyone else). Yet do mistakes that tiny bother you? I'm sorry, I don't follow. I thought an Encyclopaedia was about content. Different cultures, I guess. If the problem has arisen due to the first paragraph I wrote in my previous entry, I deeply apologize: I admit it was out of line. I've marked the text for deletion. But please, there's no need to be hostile (neither side). Regards, Jordissim (talk) 01:20, 2 June 2012 (UTC)
I ought to have thanked you for the substance of your answer, and I accept the implied rebuke. On the other hand, if you think that's animosity, you must be new to the Net! Since you ask, what offended me was not that you made what amounts to an error of punctuation, but that you presumed to mis-correct the punctuation in a paragraph attributed to me. I welcome true corrections and object to false ones. —Tamfang (talk) 02:02, 2 June 2012 (UTC)
I see what you mean, and I'm sorry. It wasn't done on purpose, I assure you. I won't make that mistake again. Regarding my misunderstaning on animosity, I am actually new on the net, and my deffensiveness has to do with my profession, I'm afraid: people tend to insult or look down on other people's work in a really difficult way to pinpoint, having to read between the lines; and I'm afraid I've become contaminated by that attitude. My world is full of politics and overinflated egoes, unluckily. So again, my apologies. Best regards, Jordissim (talk) 21:31, 2 June 2012 (UTC)
Jordissim, I do not know here you studied physics or what books you read but any physics book on classical mechanics that deals with rotating reference frames will mention the Coriolis and centrifugal (and maybe the Euler) forces. Martin Hogbin (talk) 08:20, 23 May 2012 (UTC)
Well, Martin, if you really think it's important, I studied Physics in Universitat de Barcelona, and got my PhD in high-energy physics from Universitat Autònoma de Barcelona. I also hold an Engineering degree from Universitat Politècnica de Catalunya, and am currently studying a completely unrelated third degree just because I feel like it. I work as a Project Manager in European-funded R&D projects, I am 1'88m, and have brown hair. I fail to see the point, though - how does my biography enter the equation? And yes, of course those forces will be mentioned, but in a whole different manner! All I can tell you is that bibliography is quite different depending on whether you study Engineering or Pure Physics - and terminology is, as well. Since I assume you're a phycisit as well, let me remind you how different the word "metal" is for an astronomer or for a mechanical engineer. I'm not saying the paragraph's content is wrong (did I ever?), I just said that a "force" has a very clear definition in basic Physics, and that it differs from the one in Engineering because the first courses in Physics are theoretical by nature (setting the ground rules for more in-depth subjects), whereas Engineering always takes a pragmatical approach. How can a good article first refer to something as a force, and then as a pseudoforce? It should be the other way round: establishing 1) that something looks and acts like a force, 2) but isn't, yet for most purposes, it is useful to regard is as so. And since you ask for books: "Berkeley Physics Course Vol. 1" (used in the Physics degree), or Paul A. Tippler's "Physics for scientists and engineers", 3rd edition, used in Engineering but not in Physics - in both, the Coriolis aceleration is mentioned, then its effects on a system are introduced as a pseudoforce or a fictitious force, and then the book goes on to treat it as if it were real for purely practical reasons, having already set that in reality it is not so. (Look it up for yourself). See the pattern? That's my point. It has nothing to do with the content, it's got all to do with the order.
Jordissim (talk) 00:29, 24 May 2012 (UTC)

The Coriolis effect is defined as the deflection, it is not caused by a linear force pointing to the right (in North Hemi). Here's a video http://www.youtube.com/watch?v=NpX9oXsbOfw. How does Physics explain this observable phenomenon?. Watchwolf49z (talk) 14:14, 2 November 2012 (UTC)

Jordissim, you seem to be just talking about terminology. I fully understand that CF is a pseudoforce or a fictitious force or, to use my own preferred term, an inertial force but it is common in both physics and engineering to use the term 'Coriolis force'. In my opinion the term 'Coriolis force' is much more common than 'Coriolis effect' so that is what the article should be called. Of course, the article must explain that it is an inertial force. Do we disagree about anything? Martin Hogbin (talk) 08:03, 29 May 2012 (UTC)
Martin, I certainly never doubted you understood the subject. Yet I'm not talking solely about terminology, I'm talking about accurate terminology. As I stated, any good article must assume that the reader has almost no idea on the subject at hand, and therefore it's the editor's job to drive him in the right directions, avoiding misleading twists. My idea, stated before, is to introduce the concept of the Coriolis Force in a comprehensive manner. The steps should be those I wrote right above, and copy here to reintroduce them in the subject at hand (sorry for cluttering the Talk page):
1) Introducing the Coriolis acceleration as a Newtonian "switch" among inertial and non-inertial systems;
2) Stating its effects on a system as a derived pseudoforce or a fictitious force - named as you feel like it;
3) Treat it then, and only then, as if it were real for purely practical reasons, having already set that it's but a useful simplification.
That's all. It's a question of setting a clear, direct(ed) approach to the subject, following a step-by-step method that clarifies things with the bonus of being in line with history of science.
Yet I'm not a native English speaker, and styles tend to vary depending on the country. I'm used to European Commission deliverables (a nightmarish world) and to scientific magazines in Europe, so again, it might be a matter of cultural differences. Regards, Jordissim (talk) 01:20, 2 June 2012 (UTC)

I'm deferring from a general discussion of the subject to suggest improvements to the text. The article is titled "Coriolis effect" and should focus on that. There may be a need for a separate article titled "Coriolis force". However, even for someone who has done a little study on the matter, the introductory text is extremely confusing. I would propose replacing all references to "Coriolis force" to "Coriolis effect" and either creating a paragraph to explain pseudo-forces or a whole separate article. Perhaps un-scientific, but it is fair to say this effect is a specific combination of electromagnetic and gravitation forces, any alternative explaination would require the introduction of a third (and yet to be discovered) force of nature. Starting with F = m a, it doesn't matter how small the force is, when mass is even smaller (and we are talking about individual molecules here) we are left with a large acceleration. It's not an illusion that tornadoes are almost exclusively cyclonic. Watchwolf49z (talk) 15:29, 28 October 2012 (UTC)

The Coriolis effect has nothing to do with electromagnetism, nor with gravity. It is solely a result of inertia. And the Coriolis force on something is proportional to its mass, so no matter how light or heavy, the perceived acceleration does not vary.−Woodstone (talk) 17:59, 28 October 2012 (UTC)
My issue is with the introductory paragraph, it is confusing to the casual reader. Read the first sentence, this is not how a majority of English speaking people define "Coriolis Force". Whatever it is that spins storms the same way in a hemisphere is what most people think is the effect. The body of the article is a great place to explain how it's wrong, for those who care. You use "Coriolis Force" without quotes, do you disagree with changing this to Coriolis effect through the article? Keeping in mind our goal (effective prose), both types of inertia are involved, and it causes an effect, namely spinning storms the same direction. This is the information people are looking for here. Bottom line, the definition here is inconsistant with that published by NOAA and WMO, and stands here unreferenced. If you'll review the "peer-review" archives, you'll see why I might believe the text is biased, and inappropriate for the introduction. I'm coming in from the cold here, as it were, and what I read has nothing to do with what was taught when I was in school. Gravity causes pressure, and without pressure you have no weather ... which means you're talking about something else entirely. Watchwolf49z (talk) 12:14, 30 October 2012 (UTC)
The Coriolis effect is the deflection of air moving across latitude, to the right on the Northern Hemisphere and to the left on the Southern Hemisphere (1). It is named after the French mathematician Gaspard Gustave de Coriolis (1792-1843), who studied the transfer of energy in rotating systems like waterwheels. (Ross, 1995). “Coriolis force” is a misnomer, it is an effect of a sphere’s rotation about it’s axis, and is not a force of nature (original research, my bad).[ (1) = http://oceanservice.noaa.gov/education/kits/currents/05currents1.html]
This is a vastly superior definition solely because it is fully referenced, and is in more compliance with the rules of Standard Written English. Watchwolf49z (talk) 14:35, 30 October 2012 (UTC)
That is an inferior definition, because it is specific to the case of weather systems on earth. The Coriolis effect is far more general than that. As for gravity and forces, in modern physics the Coriolis effects is just as much a force (or not) as gravity. Both act on all objects with a force that's precisely proportional to mass, and are treated on equal footing by Einstein's general relativity. It is only from the Newtonian point of view that there is a distinction between gravitational force and "pseudoforces". I don't have a strong feeling about how to handle that for this article, but it should be done carefully and correctly. Waleswatcher (talk) 17:27, 1 December 2012 (UTC)

Comment by Watchwolf49z copied from Waleswatcher's talk page[edit]

Thank you for your input, I'm assuming allowance for a brief "general discussion" here on your talk page. I'd like to direct your attention to the animation in the upper right side of the Coriolis effect article. If the upper animation is being viewed from the center of gravity, then the black dot should be showing a slight deflection, and not an absolutely straight line at any non-equitorial position. If you agree with me that this animation is in error, all's good. If you disagree, then I'll chase down the rigid math proof and post it to my sandbox. I'm afraid that we may be stuck with Weather science referencing, not many other disciplines use the effect.

The cause is due to the torque component of the acceleration from gravity at any non-equitorial position, so that when another force is applied, even if it is completely linear, the resultant force on the object will still have this rather small amount of torque. The deflection is the Work done by the torque. As another example, a bullet only experiences the Coriolis effect while in the gun barrel, once the bullet exits the applied force is removed, the bullet flies straight as viewed from the center of gravity. There's an article titled Coriolis field that seems to address your comments about Relativity. There seems to be enough scientific papers concerning the effect in Quantinum Mechanics to create a new article.

If I may be so bold, there has to be a physical reason for the predominance of cyclonic motion. Somehow, optical illusions just doesn't work for me. Watchwolf49z (talk) 14:29, 2 December 2012 (UTC)

Watchwolf49z, the upper panel of that figure is illustrating geodesic motion in an inertial frame. There is no gravity, it's simply illustrating Newton's first law. So no, I do not agree with you that there should be a deflection. I suspect you are misunderstanding what the animation is supposed to show. As for weather, the primary discipline here is physics, not meteorology. The Coriolis effect is a basic phenomenon in physics, that has applications in many fields - one of which is meteorology. Quantum mechanics has nothing to do with it, and I'm not sure what you are referring to regarding the bullet example. Waleswatcher (talk) 14:53, 2 December 2012 (UTC)
I'll be weeks chasing down the proof, and be forewarned, it will include gravity. Clearly you disagree with my statement and any further discussion will have to center on such a proof. If my math is wrong, then I am wrong. Watchwolf49z (talk) 15:44, 2 December 2012 (UTC)
If your "proof" includes gravity (in the Newtonian sense at least) then it's irrelevant to that animation. Again, I think you are mistaken about what the animation is illustrating. It's intended to show nothing or or less than geodesic motion (i.e. motion in the absence of any Newtonian forces, including gravity). The point is that geodesics in inertial frames are straight lines (no defection, that's the top panel), but those same geodesics are curved in a rotating frame (that's the bottom panel). Waleswatcher (talk) 16:25, 2 December 2012 (UTC)
The animation as a whole is demonstrating the Coriolis Force. The black dot scribes a spiral segment in the lower animation, as though a force was acting on it, when in fact the force is acting on the observer. It also demonstrates that the Coriolis Force has no effect on the system. No matter the frame of reference, measured forces on the black dot will always be zero. Let me rephrase my original question: If we give a red dot the initial velocity downward (being red dots are subject to the centripedal forces of the disk), would it show a deflection in the top animation? Watchwolf49z (talk) 04:37, 4 December 2012 (UTC)
"No matter the frame of reference, measured forces on the black dot will always be zero." If you measure the force by measuring the trajectory of the particle x(t) and then computing the second derivative of x with respect to time, multiplying that by the mass of the particle gives you F (in other words, F=ma). In a rotating frame, the acceleration is non-zero, and so is F. If instead you measure the acceleration by an accelerometer attached to the object, you will indeed get zero. But the same is true for an accelerometer attached to an object in free fall in a gravitational field. So if Coriolis or centrifugal forces aren't "real" forces for that reason, neither is gravity. As for your question, I don't understand it - the red dot is just a dot marking a point on that disk/reference frame, so what do you mean by give it a an initial velocity? Waleswatcher (talk) 06:52, 12 December 2012 (UTC)
Watchwolf49z, this is the talk page for discussion on how to improve this article not for discussion of the Coriolis force itself. As Waleswatcher says, the animation in the article is perfectly correct and shows exactly what he describes. Gravity is not included in the animation and is not relevant to a discussion of Coriolis force. I suggest that you read a good text book on classical mechanics. Martin Hogbin (talk) 08:38, 12 December 2012 (UTC)
I think I’ve found what I’m looking for, and it says I’m mostly wrong. Looks like Navier–Stokes equations are involved, so any proof will be non-rigid. There’s also no torque component involved, so statements to that effect are humbly withdrawn. John Marshall, R. Alan Plumb; Atmosphere, Ocean and Climate Dynamics; Academic Press; n.d. (© = inquiring); provides a clear and step-wise derivation of the equation of motion for fluids. George Haltimer, Frank Martin; Atmosphere, Dynamical and Physical Meteorology; McGraw-Hill; 1957 (© = Public domain); begins with this equation as (in a stationary frame of reference) daVa/dt = b + ga + F where Va = velocity, t = time, b = pressure force, ga = gravity and F = friction. From here, Haltimer/Frank explains the how and why the two pseudoforces are created from gravity (= relative gravitation + Coriolis force + centrifugal force) giving the equation of motion in a rotating frame of reference. These are set to zero for the work calculations which cuts down on the triple integrals to be resolved. It’s important to note that the two constructs are not needed to achieve a correct solution, they just eliminate some of the “nightmarish algebraic calculations”. Watchwolf49z (talk) 16:12, 15 December 2012 (UTC)
@Watchwolf49z - For clarification, are you now agreeing with the statements that the Coriolis force/effect is not limited to weather systems and systems involving gravity, but is in fact a result of taking into account the rotation of the non-inertial frame? If not, what specific information in those two references do you feel needs to be included that isn't already in the article? --FyzixFighter (talk) 17:51, 17 December 2012 (UTC)
I'm glad you asked that question. I knew right away this was what I was looking for since it fits so nicely with what is already in the article. What's written now is a fine lead-up to the concepts I posted above. I'd like to see an new section towards the bottom discussing these effects in gravity, maybe try and connect it to a vortex. Watchwolf49z (talk) 01:24, 18 December 2012 (UTC)

Proposed Changes[edit]

Aside from the above discussion, there are still a number of small housekeeping tasks in this article. Keeping to the "carefully and correctly" advice, my plan is to start with changes that should be agreeable to everyone. It's important to start out with a positive working relationship, so when disagreements arise (and they will), we'll have a solid foundation to provide what Wikipedia needs of this article. It cannot be ignored that scholarly literature regularly speaks to how confusing this subject is, even at the highest levels of academia.

These proposals are posted for comment, and if none are given or they are positive, the article itself will be changed after a week. The discussion will remain OPEN, as sometimes seeing the change in the article will expose it's weaknesses, and it's need for further editing.

  • The term "anticlockwise" appears here and there. I propose this be changed to "counter-clockwise" throughout. This change would provide consistent terminology in the article.
Done Watchwolf49z (talk) 16:06, 29 December 2012 (UTC)
  • In the History section, change the sentences `By the early 20th century the effect was known as the "acceleration of Coriolis".[6] By 1919 it was referred to as "Coriolis' force"[7] and by 1920 as "Coriolis force".[8]` to `The effect was known in the early 20th century as the "acceleration of Coriolis"[6], and by 1920 as "Coriolis force".[8]`. We'd be giving up the apostrophe for a cleaner sentence. Watchwolf49z (talk) 16:35, 22 December 2012 (UTC)
Done Watchwolf49z (talk) 16:06, 29 December 2012 (UTC)
  • We have a mixture of formats for units of measure. I propose all be giving as "mks units (Imperial units)" throughout.
Done ... except in the bathtub section and tossed ball section. Changes there go past the intent of this proposal. Watchwolf49z (talk) 16:47, 5 January 2013 (UTC)
One suggestion - rather than manually inserting the conversions to imperial units, perhaps template:convert would be a better alternative. I noticed that it's already being used in some of the same parts of the article where you put in some imperial units. Just a suggestion, though. --FyzixFighter (talk) 05:28, 7 January 2013 (UTC)
Agreed, it's just easier to type the numbers in ... I do see the advantage to using the template, just need to learn the attributes &c. Watchwolf49z (talk) 17:55, 12 January 2013 (UTC)
ReDone using convert template throughout, except the "o'clock" units. Watchwolf49z (talk) 16:07, 26 January 2013 (UTC)
  • The first sentence in the “Causes” section uses the phrase “exists only”. This is only true for the Coriolis force, and the Coriolis effect as used in Physics. However, the Coriolis effect exists in all reference frames as used in weather science. I propose changing “exists only” with “is best viewed” giving The Coriolis effect is best viewed when one uses a rotating reference frame. Watchwolf49z (talk) 15:00, 29 December 2012 (UTC)
Let's not start to obscure the facts again. In a non-rotating frame, there is no acceleration perpendicular to the flow of particles. Not in physics, not in meteorology. −Woodstone (talk) 15:54, 29 December 2012 (UTC)
Withdrawn Watchwolf49z (talk) 16:06, 30 December 2012 (UTC)
The intent of this change is to make the statement more consistent to the definition being used in this article. If you have a reference, then we can change the definition and leave this alone. Please use the preceding section for challenges to the citations and notability of usages involving gravity. Watchwolf49z (talk) 23:46, 29 December 2012 (UTC)
I'm agreeing with Woodstone here. I also don't see how changing that statement is more consistent with the definition being used in the rest of the article. Where are the other statements that you see being not consistent with that first line in "Causes"? Also, do you have a reference that the definition for the Coriolis force/effect in weather sciences is different than it is in the rest of physics? Those references you cited above do not (imo) support such a view. In the absolute frame (eq 11-6 in Haltimer & Martin), there is no Coriolis force/effect - just gravity, pressure, and friction. The Marshall & Plumb reference also repeats several times that the Coriolis force is a result of describing motion in the rotating frame (bottom of page 172 and top of page 173). For example in its GFD lab V it states: "Notice that the puck is 'deflected to the right' by the Coriolis force when viewed in the rotating frame..." and later "Viewed from the laboratory the puck moves backwards and forwards along a straight line...When viewed in the rotating frame, however, the particle is continuously deflected to the right... This is the 'deflecting force' of Coriolis." And again on pg 186: "The deflection 'to the right' by the Coriolis force is indeed a consequence of the rotation of the frame of reference: the trajectory in the inertial frame is a straight line!" That is not to say that cyclones don't spin - but an observer in space that is not rotating with the earth will not see unexplained deflection perpendicular to the direction of motion and can explain the fluid dynamics in weather systems with just gravity, pressure, and friction. It is only when we attempt to describe weather in the relative, rotating frame of the earth that we need to include the Coriolis and centrifugal forces in order to "take into account the effect of observing acceleration in a rotating frame of reference." (pg 160, Haltiner & Martin). --FyzixFighter (talk) 04:45, 30 December 2012 (UTC)
(ec)
I also disagree strongly with this proposed change, and I can't see how either of the two references Watchwolf49z has cited can be read as supporting either it or his assertion that "the Coriolis effect exists in all reference frames as used in weather science". Haltiner and Martin never use the term "Coriolis effect" at all, and Marshall and Plumb use it only three times, but never define precisely what they mean by it.
Although it's not entirely clear to me from this article's or Marshall and Plumb's exposition precisely what the term is intended to refer to, I have always presumed it referred to that part of a body's displacement relative to some chosen reference frame which is attributable to its Coriolis acceleration in that frame. But both Watchwolf49z's sources—just like all others—tell us that the Coriolis acceleration is uniformly zero in a non-rotating frame, and consequently there can be no displacement attributable to it in such a frame.
I agree that the wording of the first sentence in the Causes section could probably be improved, but I strongly disagree that this can be achieved by replacing "exists only" with "is best viewed". I would prefer it to be replaced with something like "only occurs" or "is only non-zero" . The latter substitution presumes that the term "Coriolis effect" is intended to have some at least vaguely quantitative, rather than a purely qualitative, connotation, but then Marshall and Plumb do imply just this on page 143 where they refer to it as being "weak" near the equator.
I suppose one could take the view that the Coriolis effect does actually exist in a non-rotating reference frame but just always happens to have a constant magnitude of precisely zero, but I know of no reliable source which actually does so, and I don't believe that the article's doing so would improve it.
David Wilson (talk · cont) 07:34, 30 December 2012 (UTC)
I have no problem with vectors of zero magnitude and yet still have direction, like dF/dt. Turns out Coriolis effect mass flow meters use an oscillating frame of reference (http://www.omega.com/literature/transactions/volume4/t9904-10-mass.html), which gives a zero force twice per oscillation. I think it would improve this article if the general statements were stated generally, and let the specific applications state their own frame of reference. For example, physics uses a rotating frame, meteorology uses a Newtonian frame, mass flow meters use an oscillating frame and so on. Watchwolf49z (talk) 16:12, 1 January 2013 (UTC)
How are you defining "Newtonian frame" and how is it different from a rotating frame? Is there a source that says if and how meteorology uses such a frame? --FyzixFighter (talk) 02:15, 2 January 2013 (UTC)
The definition of a Newtonian frame is left to the reader to choose. Any would be fine as long as rain is observed. I can’t source that statement, no one’s ever researched otherwise. Watchwolf49z (talk) 17:38, 3 January 2013 (UTC)
If I were to read "Newtonian frame", although I don't recall encountering it very often, I would assume it meant a frame where Newton's laws of motion apply, or in other words a classical inertial frame. Using a non-inertial frame, eg a rotating frame, Newton's laws of motion do not hold unless we bootstrap them with "fictitious" forces. From the two sources you mentioned above, I would say that meteorology does not work in a "Newtonian frame" how I have chosen to define it, but in a rotating frame. All this is to say, I think the sources we've seen indicate that the Coriolis effect of physics and meteorology are the same with physics using a general rotating frame and meteorology using the specific rotating frame of the planet. If we did meteorology in an inertial frame where we saw the earth spinning, the Coriolis effect/acceleration/force would not be observed or needed. So perhaps let me be a little bit more direct - in your statement above ("...physics uses a rotating frame, meteorology uses a Newtonian frame, mass flow meters use an oscillating frame and so on") what does the "Newtonian" of "Newtonian frame" mean to you? --FyzixFighter (talk) 19:06, 3 January 2013 (UTC)
How about that, we’re in complete and total agreement as to the definition of Newtonian frame ... go figure. The equation I posted in the previous section in stated in an inertial frame of reference, specifically one that is stationary to the stars as an approximation for the purposes of this discussion. The next step in the derivation gives us daVa/dt = b + ( gr + fCoriolis + fCentrifugal ) + F . This also stated in an inertial frame of reference, as there is nothing inherit to vector addition that changes this frame. That’s a notable example of Coriolis force/acceleration/effect existing in a non-rotating frame of reference. I ask again, why is imperative that Coriolis force/acceleration/effect not exist in such a frame? Watchwolf49z (talk) 18:38, 5 January 2013 (UTC)
Which line in the derivation (page number or equation number) is that - I'm having a little bit of a problem finding it? What I do see is after giving the equation of motion in the inertial frame (eq 11-6) where no Coriolis force is needed, it then proceeds to give the equation for dV/dt (the velocity in the rotating frame) (eq 11-7) and it is here that the real forces have to be supplemented with the Coriolis and centrifugal force in order for F/m=dV/dt to be true when V is given with respect to a rotating frame. But in the non-rotating, inertial frame only the real forces (pressure b, gravitation ga, and friction F) appear in the equation of motion. The Coriolis force only appears when we express our force balance in terms of relative, rather than absolute velocities. The Coriolis force is a consequence of the rotation of the frame of reference; when the frame of reference is not rotating, there is no Coriolis force. That's what the sources tell us (see also the opening paragraph of section 1.5 in ref 18). --FyzixFighter (talk) 03:33, 6 January 2013 (UTC)
I’m not clear on the answer to my question. Perhaps you could elaborate some on your talk page. Watchwolf49z (talk) 17:55, 12 January 2013 (UTC)
Perhaps I should clarify, “Aside from” means “at the exclusion of” information concerning the equations of motion for fluids in these proposals. “Agreeable to everyone” means that disagreement, even if politely, courteously and briefly stated, would veto the proposal. Watchwolf49z (talk) 16:06, 30 December 2012 (UTC)
  • This is a continuation of the above, AND inherits the stated disagreements (and veto). I propose changing the sentence to The Coriolis effect is only non-zero in a rotating reference frame. The issue is usage in English, where "when they are viewed" is not the exact same thing as "only exists". Now, if it's absolutely imperative the syntax be changed from from the definition, then so be it. Just remember that any unreferenced material ... in the article ... is subject to future challenge and removal per Wikipedia policy. Watchwolf49z (talk) 16:06, 30 December 2012 (UTC)
I think that I favor saying "The Coriolis effect only occurs in..." as another editor above suggested since it's not clear from any text I've seen how you actually quantify the Coriolis effect (as opposed to quantifying the Coriolis acceleration and force). IMO, that's more in-line with the sources we have. Do we have any sources that contradict this? --FyzixFighter (talk) 02:15, 2 January 2013 (UTC)
The equation for the deflection can be deduced from the equations of the observed and observer. It’s a lot of analytical geometry, but it can be done. The derivative of this equation establishes existence in a non-rotating frame. The proof of this is in any first year calculus book. I think we both know this proposal is going to be withdrawn. I’m sure the reference to the statement in the article explains why the derivative is discontinuous here as well. Watchwolf49z (talk) 17:38, 3 January 2013 (UTC)
Withdrawn - Hallelujah Watchwolf49z (talk) 16:47, 5 January 2013 (UTC)
  • In the Rossby number section, a baseball example would be more accessible to the intended reader. I propose replacing the garden material with (and my arithmetic should be checked): A baseball pitcher may throw the ball at U = 45 m/s (100 mph) for a distance of L = 18 m (60 ft). The Rossby number in this case would be 32,000. Needless to say, one does not worry about which hemisphere one is in when playing baseball.Watchwolf49z (talk) 18:38, 5 January 2013 (UTC)
Done Watchwolf49z (talk) 16:22, 12 January 2013 (UTC)
Done Watchwolf49z (talk) 16:22, 12 January 2013 (UTC)
  • Draining in bathtubs and toilets - It looks like the paragraphs got mixed up. The information in the second paragraph is far more notable than in the first. I find it reads just as well both ways, although reversing the paragraphs doesn’t create a contrast. The information flows into each other quite well. I propose reversing the order of these two paragraphs and deleting the phrase "In contrast to the above". Watchwolf49z (talk) 17:55, 12 January 2013 (UTC)
Done Watchwolf49z (talk) 19:32, 19 January 2013 (UTC)
  • Distant Stars - This is currently unreferenced. I have the feeling it can be found in all the archives, and someone will need to track it down. On the other hand, I’m not seeing how this is notable. Astronomers just point their polar axis toward Polaris, stars then track a straight line across the eyepiece. I propose deleting this section entirely, based on lack of notability. Watchwolf49z (talk) 17:55, 12 January 2013 (UTC)
This section was inserted after an edit war with an editor with a rather confused mixup with orbital equations. It represents the most pure case, where nothing really moves; there is only rotation. Let's keep it. −Woodstone (talk) 19:04, 12 January 2013 (UTC)
Do you remember how long ago? That's where the reference is I'll bet. Throw up the footnote and it'll be good, far and away more notable than fruit flies. Watchwolf49z (talk) 19:57, 12 January 2013 (UTC)
The current version was entered on 2011-09-30. There is no reference on talk, but it is a straightforward application of the general formula, so none is needed. But isn't it insightful to realise that the curved path of Sun during the day is mostly due to the combined Coriolis and Centrifugal forces?−Woodstone (talk) 04:53, 13 January 2013 (UTC)
Yeah, this would be an edit war alright. After reading WP:OR, I'm left with the impression that this section would cause us to be denied "Good article" grade. Perhaps if the insight was more explicitly stated the reader could understand which secondary source this illustrates. I just don't know, as long as one of us thinks it's notable, then it belongs in the article. Watchwolf49z (talk) 15:14, 14 January 2013 (UTC)
Withdrawn. Watchwolf49z (talk) 19:32, 19 January 2013 (UTC)

An Aside[edit]

I'd like to find out what everybody thinks of the idea of moving Tossed ball on a rotating carousel sun-section from Special Cases into it's own section, and then putting this new section just after History section. The reason is to get a simple and more detailed example to the readers' eyes before we go into the formula and causes. I've chosen this particular example because it is fairly common in the literature, and footnoting a reference would be almost a "pick-em" decision. Does anyone have a favorite, or can I just throw one up that substantiates the statements in the article? Watchwolf49z (talk) 16:19, 24 January 2013 (UTC)

  • An IP editor tagged the Bullet sub-section for a citation. This is already given in the Causes section as Littlewood (1953). I propose just adding the footnote and clear the tag. Watchwolf49z (talk) 16:07, 26 January 2013 (UTC)
Done Watchwolf49z (talk) 17:39, 2 February 2013 (UTC)
  • In the Bathtub section, we have the parenthetical phrase once per day at the poles, once every 2 days at 30 degrees of latitude. I was just in Miami, I rotated once per day. I propose just deleting the whole phrase as not relevant to the statement. Watchwolf49z (talk) 16:07, 26 January 2013 (UTC)
This refers to the factor sin φ, which appears in the horizontal component of the rotation at latitude φ. There is no Coriolis force on the equator. But agree to omit in this context. −Woodstone (talk) 22:26, 26 January 2013 (UTC)
Done Watchwolf49z (talk) 17:39, 2 February 2013 (UTC)

I've undid a couple edits, the IP edit is obvious, the other was because it was duplicated in the references. I'm okay with this duplication and agree that the Persson (1998) is a good selection for "Further Reading". Watchwolf49z (talk) 17:39, 2 February 2013 (UTC)

Thank you, Woodstone ... there's a bit of dialog from last week on his talk page. I'm still thinking of bringing in Waleswatcher in on this, GK can't just call anyone he pleases a vandal. Watchwolf49z (talk) 13:37, 3 February 2013 (UTC)
Please check you minds whether an empty link is worthy of explaining the coriolis force. Vandal might not be the best characteristic of an empty mind. Gabriel Kielland (talk) 20:49, 3 February 2013 (UTC)
Two points:
  • Copies of articles once pointed to by dead links can often be found by using the Wayback Machine, as in fact was the case for this particular "empty link".
  • While you're entitled to remove dead links from an external links section, there is no requirement—as far as I know—that this must be done immediately. A preferable alternative, in my opinion, is to tag the link with a Dead link template. This should increase the chances that someone who might be a little more enterprising than you are will be able to track down a live link to a copy of the original resource.
David Wilson (talk · cont) 12:49, 4 February 2013 (UTC)
  • The Littleton (1953) reference has an addition statement. I propose moving it into the article itself in the Bullet section. Watchwolf49z (talk) 17:39, 2 February 2013 (UTC)
  • There wasn't any discussion about moving Tossed ball on a rotating carousel sun-section up in the article. I propose that now, let's see what it looks like. Watchwolf49z (talk) 17:39, 2 February 2013 (UTC)

I undid the IP edit, 1835 is the correct date of publication (see `further reading` section). However, the added `de` might be technically correct, as in Gaspard-Gustave de Coriolis, I don't know enough Italian to know the difference. Watchwolf49z (talk) 20:57, 4 February 2013 (UTC)


I'm sorry that my comment isn't constructive in that it doesn't offer an alternative, but it seems to me that this article is confusing in that it mixes the effects of an object moving over a rotating body when it is NOT BOUND to that rotating body (e.g. throwing an object to someone on a turntable) with the effects of an object moving over a rotating body when it IS BOUND to that body (e.g. weather systems on earth, figure skater spin, office chair spin). THe former of these is simply a frame of reference effect, which is pretty simple; the latter is conservation of angular momentum (and the coriolis effect). What's more the deflection in trajectory is opposite for the two effects. ??

PhilDWhite (talk) 21:34, 6 February 2013 (UTC)

Yes, the article is incomplete. You are certainly welcome to help, there's still quite a bit that can be said in this matter. The physics presented is sound, but the meteorology is somewhat lacking. All I ask is be quick to revert your own edits if someone voices an objection. = Watchwolf49z (talk) 16:22, 8 February 2013 (UTC)
@PhilDWhite - do you have a source that makes this distinction? At least in the case of weather systems, the two sources mentioned previously (Marshall et al. and Haltimer et al.), which talk about this in the meteorology context, seem to derive the Coriolis force/effect based on the transformation from the non-rotating to the rotating frame, which to me would seem to be true for both bound and unbound objects. From my reading, I don't see this distinction made in the literature, but perhaps there's a source out there that does?
I do not believe that there is such a distinction. Martin Hogbin (talk) 13:41, 20 February 2013 (UTC)
If the objects aren't bound to the sphere, wouldn't they fly off into space? Weather occurs in atmospheres which by definition is a fluid bound by gravity. = Watchwolf49z (talk) 15:17, 21 February 2013 (UTC)
Yes, so what? Martin Hogbin (talk) 16:58, 21 February 2013 (UTC)
Well ... it would improve the article if this was made more clear? = Watchwolf49z (talk) 18:03, 21 February 2013 (UTC)
What exactly needs to be made clear? We need to make clear that is one Coriolis force, which is an inertial force found only on rotating frames of reference, but it can appear in a variety of circumstances. Do you agree? Martin Hogbin (talk) 18:22, 21 February 2013 (UTC)
By the way, why do you mark your comments as minor edits they are just normal edits and if you mark them as minor some interested parties may miss them. Martin Hogbin (talk) 18:23, 21 February 2013 (UTC)
Well, that would depend on precisely what assumptions you're making, which aren't spelt out precisely enough to give a definite answer to the question. If you're assuming that the force of gravity on a body at rest on the surface of the Earth were somehow suddenly turned off, a more apt description for its initial motion would be "float off" rather than "fly off". In the rotating frame of the Earth the only appreciable force or pseudoforce initially acting on the body would be the centrifugal, which would produce an acceleration of only about 3.3cm/sec2 at the equator. After 10 seconds a body starting from rest on the equator would have risen only about 1.5 m and be travelling at only about 1.1km/hr, almost vertically upwards relative to the surface of the Earth, and the Coriolis force on it would still be negligible. After 100 seconds it would still have risen only about 16.5 m and be travelling at about 11km/hr. At that speed, air resistance would be enough to start reducing its upward acceleration somewhat. Nevertheless, it would eventually pick up sufficient speed for the Coriolis force to produce a noticeable and gradually increasing drift to the west.
But as long as we're going to make counterfactual hypotheses—i.e. that a body is not subject to gravity—why should we assume that it starts from rest on the surface of the Earth? Suppose instead that it's propelled westward down the centre of a perfectly evacuated toroidal tube encircling the Earth's equator. Suppose that the centre of the tube is at a distance r from the centre of the Earth, and that the body is propelled at speed ω r, where ω is the angular velocity of the Earth's rotation. In the rotating frame of the Earth The body is subject to a vertically upward centrifugal force of ω2 r and a vertically downward Coriolis force of 2 ω2 r. The resultant downward pseudoforce of ω2 r is exactly enough to prevent the body from "flying off" to the upper surface of the tube, and will keep it moving at speed ω r along the tube's centre. With respect to the distinction you are trying to draw between bodies "bound to the sphere" and ones "not bound" to the sphere, would this body count as belonging to the former or the latter category? And, more to the point, why would it belong to either one, rather than the other?
While I don't want to deny categorically that any such distinction can be drawn, I have to say that, like Martin Hogbin, I haven't the foggiest idea what it is that you're trying to make "more clear". Unless you're really able to make it more clear on this talk page, I don't think it would be possible for you to do so in the article itself.
David Wilson (talk · cont) 03:32, 22 February 2013 (UTC)
P.S. To forestall any quibbles that my toroidal tube example wouldn't work because of the Earth's motion around the Sun—or various other practical difficulties—I should acknowledge that yes, I realise that this would be so, and that I have simply ignored them.
David Wilson (talk · cont) 03:53, 22 February 2013 (UTC)

Intuitive explanation of the Coriolis effect[edit]

I made an edit 2/17/2014 by adding a paragraph to the intuitive explanation of the Coriolis effect. It was removed 6 days later by tentinator. I would like to be given a reason for its removal. The explanation I gave is intuitive, accurate, and easy to understand. A Thousand Clowns (talk) 02:30, 24 February 2014 (UTC)

The intuitive explanation is awful! I cannot understand it. There's a lot of jargon in it. The bottom line is that your rotational velocity of the earth declines as you move to the poles and vice versa. Thus, if you start at the equator, (which has the highest rotational velocity), because of conservation of momentum, as you move north (or south) you retain the eastward momentum you had at the equator. Meanwhile, the Earth beneath you is slowing down, so you will move to the east relative to the ground. When proceeding toward the equator, you have a small rotational velocity, thus as you move the Earth's surface under you appears to speed up, and you will move west relative to Earth's surface. If there's no objections, I will attempt to rewrite this section presently. Warren Platts (talk) 15:57, 30 March 2014 (UTC)
Many have gone before you to try for a better intuitive explanation. Note that it should not only explain the effect on North/South movements, but also for East/West, which is equally large (and preferably also for up/down). −Woodstone (talk) 16:52, 31 March 2014 (UTC)

Contradiction regarding vortex circulation in schematic figures[edit]

The photo showing the vortex over iceland says the vortex spins 'counter-clockwise', whereas the figure of the earth below, showing the vortex circulation patterns, shows vortices spinning clockwise on the northern hemisphere. One of the two must be wrong, apparently. — Preceding unsigned comment added by 131.188.166.21 (talk) 14:26, 14 April 2014 (UTC)

Both are correct. They occur in different circumstances. The first shows airflow caused by air pressure differences, the second the trajectory of a floating object in absense of driving forces. −Woodstone (talk) 16:16, 14 April 2014 (UTC)