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I have moved some history details from lead to the History section. I note that a reference cited in [[Theory of tides]] (http://siam.org/pdf/news/621.pdf) attributes the first recognition of Coriolis effect in tides to [[Colin Maclaurin]] not [[Pierre-Simon Laplace]]. No date is given in the ref so I have not made any changes. --[[User:Kvng|Kvng]] ([[User talk:Kvng|talk]]) 20:35, 2 July 2012 (UTC)
I have moved some history details from lead to the History section. I note that a reference cited in [[Theory of tides]] (http://siam.org/pdf/news/621.pdf) attributes the first recognition of Coriolis effect in tides to [[Colin Maclaurin]] not [[Pierre-Simon Laplace]]. No date is given in the ref so I have not made any changes. --[[User:Kvng|Kvng]] ([[User talk:Kvng|talk]]) 20:35, 2 July 2012 (UTC)

== cyclonic storm ==

I did not read the whole article so maybe my point was clarified in another section. The diagram of winds into the low pressure shows a north wind and south wind deflected in opposite directions. It seems to me that they would both deflect east (in the Northern Hemisphere), but since the rotating Earth has a faster linear speed in the south, the deflection would be geater for a south wind, forcing an overall counterclockwise rotation.

Revision as of 12:22, 8 July 2012

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Vandalism

Blatant vandalism inn the section on Bathtubs/Toilets. "Big floppy donkey dick"

173.79.117.146 (talk) 19:45, 20 February 2012 (UTC)[reply]

It was reverted by a bot within a minute, you're seeing a cached page. Materialscientist (talk) 00:00, 21 February 2012 (UTC)[reply]

Question

What does this mean from the article: Perhaps the most important instance of the Coriolis effect is in the large-scale dynamics of the oceans and the atmosphere. In meteorology and oceanography, it is convenient to postulate a rotating frame of reference wherein the Earth is stationary. In accommodation of that provisional postulation, the otherwise fictitious centrifugal and Coriolis forces are introduced.

Why are the otherwise fictirious forces now real due to a purely abstract analytical formulation (fixed earth and rotating frame). There must be something missing in this explanation such as the motion constraints introduced through the atmospheric friction cause a real force that is like coriolis. the example I can think of is the merry go round. You are constrained to follow a curved path and to do so the seat pushes on you with a real force of opposite sign but equal magnitude as the centrifugal force (i.e. the centripetal acceleratoin required to make you follow th edge of the merry go round) Skimaniac (talk) 04:56, 3 March 2012 (UTC)[reply]

The Coriolis force is an inertial (also called fictitious) force that is only present in rotating frames of reference. Newton's laws only apply in inertial frames. If we wish to use them, unchanged, in a non-inertial (for example rotating) frame we can do so by inventing some new forces. The Coriolis force is one example of such a force.
If the article does not make this clear perhaps you might suggest ways in which it could. Martin Hogbin (talk) 10:13, 3 March 2012 (UTC)[reply]

If only I could. I am quite familiar with the coriolis apparent acceleration in trajectories which is why I have a hard time accepting the common explanation of coriolis for spinning. As I stated earlier, the centripetal and the centrifugal terms are of equal magnitude and opposite sign. the centripetal force is put on the body by some structure or force that enforces the trajectory constraint. Since the air is flowing into the low pressure at the center of the hurricane and the low is somewhat "stuck" to the earth's surface through "friction" (aka viscosity) effects, the low is dragging the pressure field around with the earth's rotation. Since the clouds of the hurricane stay with the earth as seen from an inertial observer from space, viscosity effects are dragging the air around with the earth. I believe the poor explanations arise from writing the dynamics of the air particle in the earth fixed (non-inertial and spinning) frame where the coriolis apparent acceleration properly appears and people see that and blame it on that term. Skimaniac (talk) 18:02, 3 March 2012 (UTC)[reply]

Is this image you used incorrect?

Hi, I'm not entirely sure if this is the right place to post this so please forgive me if it's not. I was just reading up on some facts about coriolis effect and was very interested in this article, but i couldn't get my head around this image. given what i've been reading, is this going the opposite direction that it should be?

http://upload.wikimedia.org/wikipedia/commons/6/69/Coriolis_effect14.png

any responce would be greatly appreciated Dean Deanobrowne (talk) 00:29, 19 March 2012 (UTC)[reply]

The picture shows inertial circles, being the path a particle would follow if there were no forces on it. So no air pressure differential, no drag (friction). As the caption states, the direction is opposite to the case where the air pressure gradient is the driving force as in a depression. −Woodstone (talk) 06:14, 19 March 2012 (UTC)[reply]

 Fixed (I think) [No fix was needed]

(edit conflict) Thanks for letting us know about this—here is indeed exactly the right place to post about difficulties with understanding the article. Because of the diagram's location and the incompleteness of the first part of the caption, it may not be entirely clear that it's intended to illustrate airflows around high-pressure areas. I presume Deanobrowne was might be having difficulty because he quite reasonably assumed it was supposed to be illustrating airflows around depressions. If Woodstone's explanation and the amendment I have made to the article hasn't cleared up the problem, a follow-up on Deanobrowne's part would be welcome.
David Wilson (talk · cont) 06:38, 19 March 2012 (UTC)[reply]
The picture shows the theoretical trajectory of a particle under no force other than inertial (fictitious). A high pressure area would exert a real (not fictitious) force. Reverted the "fix".−Woodstone (talk) 07:01, 19 March 2012 (UTC)[reply]
Yes. Apologies for the blunder and the bogus "fix". I had somehow got the nonsensical notion into my head that circular flow couldn't occur without a pressure gradient. A more careful reading of the article's section on inertial flow, or your above explanation, ought to have been enough to dispel it, but I only skimmed them without properly taking them in. Perhaps it might be worth adding a slightly fuller explanation of why the flows have the directions they do to the section on inertial flow, although it's probably also worth waiting until Deanobrowne has explained why he thinks they should be in the opposite directions.
David Wilson (talk · cont) 10:40, 19 March 2012 (UTC)[reply]
My apologies. And thank you for clearing this up with me. I'm very new to this and I just needed to keep reading over it. I think i'm confusing it with hurricanes. For instance even though, in the north, the flow is thrown into a clockwise direction, would a hurricane be forced into counter-clockwise? Im sorry if this is already explained

Deanobrowne (talk) 15:00, 23 March 2012 (UTC)[reply]

Deanobrowne, have a look at the diagram above the one you asked about:
As air moves toward the center of a low pressure system from all directions, it is deflected to the right. The result is counterclockwise flow, counterintuitively following a trajectory which curves to the left. Rracecarr (talk) 20:11, 26 March 2012 (UTC)[reply]

CORIOLIS EFFECT: AN INTELLECTUAL ILLUSION

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)[reply]

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)[reply]
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)[reply]
What's an example of a fictitious centripetal force? —Tamfang (talk) 04:07, 23 May 2012 (UTC)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]
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)[reply]

The Euler force

The lead currently says, 'When Newton's laws are transformed to a rotating frame of reference, the Coriolis and centrifugal forces appear'. In general, there is also the Euler force, unless the reference frame is rotating with constant angular velocity. I cannot think of any way to add this neatly. Any ideas? Martin Hogbin (talk) 10:18, 24 March 2012 (UTC)[reply]

How about, ' 'When Newton's laws are transformed to a uniformly rotating frame of reference, the Coriolis and centrifugal forces appear.'? Martin Hogbin (talk) 09:19, 25 March 2012 (UTC)[reply]
Good. Done. Rracecarr (talk) 19:56, 26 March 2012 (UTC)[reply]

Second paragraph suggested modifications

So how about this for the second paragraph? I think the terms are introduced in a more orderly fashion. What do you think? "Newton's laws of motion govern the motion of an object in a (non-accelerating) inertial frame of reference. When Newton's laws are transformed to a uniformly rotating frame of reference, there's a need to introduce additional accelerations, and thus, forces, in order to allow the application of Newton's laws to the system. Those are the Coriolis and the centrifugal forces, and are termed either as inertial, fictitious or pseudo forces[1] due to the fact that they are correction factors that do not exist in a non-accelerating or inertial reference frame, and are added ad hoc in order to make the equations work from the Newtonian perspective of an observer within the rotating non-inertial frame, as opposed to the straight line perceived by an external, inertial observer. Both forces are proportional to the mass of the object. The Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to its square. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object's speed in the rotating frame. The centrifugal force acts outwards in the radial direction and is proportional to the distance of the body from the axis of the rotating frame." Jordissim (talk) 00:37, 16 June 2012 (UTC)[reply]

The statement about "need to introduce ... forces" is rather weak. The transformation generates them outright. They are not correction factors, but direct consequences of the transformation. −Woodstone (talk) 09:41, 16 June 2012 (UTC)[reply]
Ok, then. Even though I don't fully agree with you -you're right if you think a mathematical transformation has a physical meaning, which I don't, since I believe the Universe doesn't do maths (that's an off-topic not to be treated here)-, I think the structure I proposed is better than the one in place. So, how would you change the phrases you don't like? Any ideas? I'm not very good at writing, and when I tried incorporating your point I didn't like the result -due to my lack of skill, basically... Jordissim (talk) 23:10, 18 June 2012 (UTC)[reply]

History

I have moved some history details from lead to the History section. I note that a reference cited in Theory of tides (http://siam.org/pdf/news/621.pdf) attributes the first recognition of Coriolis effect in tides to Colin Maclaurin not Pierre-Simon Laplace. No date is given in the ref so I have not made any changes. --Kvng (talk) 20:35, 2 July 2012 (UTC)[reply]

cyclonic storm

I did not read the whole article so maybe my point was clarified in another section. The diagram of winds into the low pressure shows a north wind and south wind deflected in opposite directions. It seems to me that they would both deflect east (in the Northern Hemisphere), but since the rotating Earth has a faster linear speed in the south, the deflection would be geater for a south wind, forcing an overall counterclockwise rotation.

  1. ^ Bhatia, V.B. (1997). Classical Mechanics: With introduction to Nonlinear Oscillations and Chaos. Narosa Publishing House. p. 201. ISBN 81-7319-105-0.
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