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The Cole Siphon


Guest Aemilius

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Guest Aemilius

Theory Of Indefinite Operation.... Running The Experiment

As this thought experiment begins (seen in the diagram at the moment the left end of the siphon, already filled with fluid, is exposed to atmospheric pressure) gravity will immediately begin to do work on the fluid within the siphon due to the excess of weight on the left by forcing the column of fluid within the left tube of the siphon to begin falling. Fluid will begin to exit the end of the tube on the left from a region of higher pressure (fluid pressure at the the end the tube that terminates in mid air) to a region of lower pressure (atmospheric pressure at the air gap) with a force equal to the difference in weight between the two columns due to a difference in height.

 

Resulting directly from the work being done on the fluid within the siphon by gravity, in forcing the fluid column on the left to begin falling, atmospheric pressure will immediately begin to do work on the fluid in the resevoir. Fluid will begin to enter the immersed end of the tube on the right from a region of higher pressure (fluid pressure in the resevoir) to a region of lower pressure (fluid pressure at the end of the immersed tube) with a force equal to the difference in weight between the two columns due to a difference in height.

 

Once started, the operation of a siphon will continue for as long as a potential difference continues to exist between the weights of the two columns due to a difference in height, and a steady supply of fluid is available. The magnet (static magnetic field) installed around the siphon tube in close proximity to the surface of the fluid in the resevoir will act indefinitely (downward diamagnetic repulsion of the fluid) to maintain a depression on the surface of the fluid. Two distinct fluid levels will then exist side by side in the same resevoir, enabling continuous flow of fluid by allowing for the tube on the left to indefinitely terminate in mid air at a lower level than the level at which the tube on the right emerges from the surface of the fluid in the resevoir while exposed to the same level of atmospheric pressure.

 

As this process continues, the total volume of fluid in the system will not change, and for every drop of fluid that's added to the resevoir by the tube on the left, a drop of fluid will be removed from the resevoir by the tube on the right. Because of that, the lower fluid level in the depression caused by the magnet (static magnetic field) and the fluid in the rest of the resevoir under normal atmospheric pressure will both remain constant as the normal operation of the siphon continues.

 

Under the conditions outlined above the fluid in the system will continue to circulate indefinitely.

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Guest Aemilius

Hey CraigD....

 

CraigD "It’s not a perpetual motion machine...."

 

We're in complete agreement there, it's clearly a siphon.... Not a perpetual motion machine.

CraigD "....because, no matter how it’s done – magnetics, a downward air jet, a simple dam between the left and right sides of reservoir, etc. – mechanical work must be done to keep the surface of the water near the left end of the tube lower than near the right end. It won’t stay in that condition without work...."

 

I'm going to just challenge that as false. To support it you'd have to explain how the permanent magnet (static magnetic field) in this scenario is doing mechanical work to maintain the depression on the surface of the fluid.... No work needs to be done by the permanent magnet (static magnetic field) to keep the surface of the fluid near the left end of the tube lower than it is near the right end. It will stay in that condition without work.

 

CraigD "This work could be done by a motor driving some sort of pump, including something exotic like the “magnetic dimple maker” scheme Aemilius sketched and described above...."

 

I'll challenge that as false too. To support it you'd have to explain how mechanical work similar to the work done by a pump can be done by a permanent magnet (static magnetic field) and/or give an example of how it could do mechanical work similar to something like a pump.... No work can be done by the permanent magnet (static magnetic field) in this scenario that's in any way comparable to the work done by a pump that requires the input of energy (gas, electricity, hydraulic pressure, etc.).

 

Do you still stand by these remarks from post 22 CraigD?

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I'll just go ahead and assert here that the only force needed to do work on this system is gravity in response to an imbalance within the siphon tube that causes a potential difference to exist between the respective weights of the two columns. The magnet can't do work on the system to maintain the depression, but it can act on the system to maintain the depression. In other words.... The depression on the surface of the fluid is simply the diamagnetic fluid's reaction to the static magnetic field.... not work.

 

And I am going to assert here that it is a violation of our rules here for you to simply claim anything just because YOU say so. NOW, show some science to support your assertions!!! Don't just claim there is some alleged imbalance. Show some real numbers for the forces at work and prove your assertion.

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Theory Of Indefinite Operation.... Running The Experiment

As this thought experiment begins (seen in the diagram at the moment the left end of the siphon, already filled with fluid, is exposed to atmosheric pressure) gravity will immediately begin to do work on the fluid within the siphon due to the excess of weight on the left by forcing the column of fluid within the left tube of the siphon to begin falling. Fluid will begin to exit the end of the tube on the left from a region of higher pressure (fluid pressure at the the end the tube that terminates in mid air) to a region of lower pressure (atmospheric pressure at the air gap) with a force equal to the difference in weight between the two columns due to a difference in height.

 

 

Resulting directly from the work being done on the fluid within the siphon by gravity, in forcing the fluid column on the left to begin falling, atmospheric pressure will immediately begin to do work on the fluid in the resevoir. Fluid will begin to enter the immersed end of the tube on the right from a region of higher pressure (fluid pressure in the resevoir) to a region of lower pressure (fluid pressure at the end of the immersed tube) with a force equal to the difference in weight between the two columns due to a difference in height.

 

Once started, the operation of a siphon will continue for as long as a potential difference continues to exist between the weights of the two columns due to a difference in height, and there's a steady supply of fluid is available. The magnet (static magnetic field) installed around the siphon tube in close proximity to the surface of the fluid in the resevoir will act indefinitely (downward diamagnetic repulsion of the fluid) to maintain a depression on the surface of the fluid. Two distinct fluid levels will then exist side by side in the same resevoir, enabling continuous flow of fluid by allowing for the tube on the left to terminate in mid air at a lower level than the level at which the tube on the right emerges from the surface of the fluid in the resevoir while exposed to the same level of atmospheric pressure.

 

As this process continues, the total volume of fluid in the system will not change, and for every drop of fluid that's added to the resevoir by the tube on the left, a drop of fluid will be removed from the resevoir by the tube on the right. Because of that, the lower fluid level in the depression on the surface of the fluid caused by the static magnetic field and the fluid in the rest of the resevoir under normal atmospheric pressure will both remain constant during the normal operation of this siphon.

 

Under the conditions outlined above the fluid in the system will circulate indefinitely.

 

 

I know you claim it is not but I think you are trying to describe a perpetual motion machine, here's why...

 

If as you say the magnetic flied would maintain the dimple then the water would flow freely for as long as the magnetic field stayed on, I say stayed on because I doubt a static magnetic flied would have the effects you suggest, can you show me some support for this?

 

If as you claim the magnetic field would make a dimple in the fluid would it not also prevent a free flow in the siphon?

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Guest Aemilius

C1ay "And I am going to assert here that it is a violation of our rules here for you to simply claim anything just because YOU say so. NOW, show some science to support your assertions!!! Don't just claim there is some alleged imbalance. Show some real numbers for the forces at work and prove your assertion."

 

Right, don't just take my word for it....

 

CraigD "Since the end of the left tube is lower than where the right tube enters the water, per the

simplified, approximate hydrostatic pressure equation, there will be pressure difference,

where is the height difference, the density of the fluid and the acceleration of gravity. So fluid will flow from the right end of the tube to the left end. Because the tube is higher in places than the water surface, this is called a siphon. As long as there’s a height difference, there will continue to be pressure, and right-to-left flow."

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Guest Aemilius

Hey Moontanman....

 

Moontanman "If as you say the magnetic flied would maintain the dimple then the water would flow freely for as long as the magnetic field stayed on...."

 

That's exactly what I'm saying, and a 5 Tesla permanent magnet will "stay on" for a very, very long time. I'm also saying that once installed, the permanent magnet (static magnetic field) would act indefinitely to maintain the depression on the surface of the fluid in the resevoir without doing any work on the system. CraigD has said that work must be done to maintain the depression. Obviously, I'm waiting for his response to post 36. If he can't show either one of these.... how the permanent magnet (static magnetic field) is doing work in this scenario to maintain the depression.... why any other force would be needed to do work on the system for the siphon to operate normally.... then my Theory of Indefinite Operation stands. If he can show either one of those it falls.

 

Moontanman "....I say stayed on because I doubt a static magnetic flied would have the effects you suggest, can you show me some support for this?"

 

The diamagnetic effect is well known and I think there's good supporting evidence. For example.... a 10 gram mouse has been levitated by reseachers (I think it was a 17 Tesla superconducting magnet). So a little conjecture....

 

A 5 Tesla permanent magnet is currently under development, that's why I chose it for the strength of the permanent magnet (static magnetic field) in the thought experiment.... it currently exists. I reason (loosely) that if a 17 Tesla magnet can levitate a 10 gram mouse, consisting of let's say 60 percent, or 6 cubic centimeters of water, the primary diamagnetic substance in the mouse accounting for the effect, then a 5 Tesla permanent magnet like the one I referred to could reasonably be expected to be capable of displacing around 2 or 3 grams, or 2 or 3 cubic centimeters of water at the surface. Naturally, a larger effect would be desirable, so I was also thinking perhaps some solution of bismuth chloride (bismuth is roughly twenty times more diamagnetic than water) may enhance the weak magnetic susceptibility of the water and increase both the diamagnetic effect and the size of the depression. I wouldn't project what that difference might be, it might have to be determined by actual experiments. Hope that makes sense, let me know.

 

Moontanman "If as you claim the magnetic field would make a dimple in the fluid would it not also prevent a free flow in the siphon?"

 

That's a good question.... naturally I can't be sure, but I don't think it will prevent flow. That might have to be determined by actual experiments too.

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Hey Moontanman....

 

Moontanman "If as you say the magnetic flied would maintain the dimple then the water would flow freely for as long as the magnetic field stayed on...."

 

That's exactly what I'm saying, and a 5 Tesla permanent magnet will "stay on" for a very, very long time. I'm also saying that once installed, the permanent magnet (static magnetic field) would act indefinitely to maintain the depression on the surface of the fluid in the resevoir without doing any work on the system. CraigD has said that work must be done to maintain the dimple. Obviously, I'm waiting for his response to post 36. If he can't show either one of these.... how the permanent magnet (static magnetic field) is doing work in this scenario to maintain the dimple.... why any other force would be needed to do work on the system for the siphon to operate normally.... then my "Theory of Indefinite Operation" stands. If he can show either of those it falls.

 

Moontanman "....I say stayed on because I doubt a static magnetic flied would have the effects you suggest, can you show me some support for this?"

 

The diamagnetic effect is well known and I think there's good supporting evidence. For example.... a 10 gram mouse has been levitated by reseachers (I think it was a 17 Tesla superconducting magnet). So a little conjecture....

 

A 5 Tesla permanent magnet is currently under development, that's why I chose it for the strength of the permanent magnet (static magnetic field) in the thought experiment.... it currently exists. I reason (loosely) that if a 17 Tesla magnet can levitate a 10 gram mouse, consisting of let's say 60 percent, or 6 cubic centimeters of water, the primary diamagnetic substance in the mouse accounting for the effect, that a 5 Tesla permanent magnet like the one I referred to could reasonably be expected to be capable of displacing around 2 or 3 grams, or 2 or 3 cubic centimeters of water at the surface. Naturally, a larger effect would be desirable, so I was also thinking perhaps some solution of bismuth chloride (bismuth is roughly twenty times more diamagnetic than water) may enhance the weak magnetic susceptibility of the water and increase both the diamagnetic effect and the size of the dimple. I wouldn't project what that difference might be, it might have to be determined by actual experiments. Hope that makes sense, let me know.

 

Moontanman "If as you claim the magnetic field would make a dimple in the fluid would it not also prevent a free flow in the siphon?"

 

That's a good question.... naturally I can't be sure, but I don't think it will prevent flow. That might have to be determined by actual experiments too.

 

 

I look forward to seeing your experiment, the solution of bismuth makes sense, how large is the bore of your proposed siphon? I will make a prediction, the magnet will either have no effect, or if it does it will stop the flow in the siphon instead of allowing it to flow.

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Moontanman "....how large is the bore of your proposed siphon?"

 

I'm not sure. I think maybe I better just focus on establishing the theory first. I only thought of this about two or three weeks ago so, hopefully, you'll forgive me for not having worked out all the myriad engineering details yet. If I become reasonably convinced of viability I'll start to think in those terms.

 

Moontanman "Oh yeah, one more question, do magnetic fields scale up linearly?"

 

Maybe CraigD can answer that.... I'm just a High School dropout man!

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I've done a bit of looking into it, if your fluid is a super conductor then maybe it will hold a plug of the fluid but it would not allow flow, it looks to me that such materials are not just levitated but actually held fast by the magnetic field. JMHO

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Oscillating fields? Superconducting fluids? Plugs that won't flow? That must be some really good bud man! I just want to read what CraigD has to say about post 36.... later.

 

Oh yeah, the experiments.... I have a feeling it might be a while before I can just order a 5 Tesla permanent magnet from Edmund Scientific.

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C1ay "And I am going to assert here that it is a violation of our rules here for you to simply claim anything just because YOU say so. NOW, show some science to support your assertions!!! Don't just claim there is some alleged imbalance. Show some real numbers for the forces at work and prove your assertion."

 

Right, don't just take my word for it....

 

CraigD "Since the end of the left tube is lower than where the right tube enters the water, per the

simplified, approximate hydrostatic pressure equation, there will be pressure difference,

where is the height difference, the density of the fluid and the acceleration of gravity. So fluid will flow from the right end of the tube to the left end. Because the tube is higher in places than the water surface, this is called a siphon. As long as there’s a height difference, there will continue to be pressure, and right-to-left flow."

 

Wrong answer!!! I expect to see some detailed proof of your assertion here, not a repost of someone else's post that describes one aspect of your assertion. It's no one's responsibility here to disprove your assertion, it's yours alone to prove it and the rules clearly state it. Do not think you can simply come here and play by whatever rules you like. Get busy posting some supporting science.

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C1ay "I expect to see some detailed proof of your assertion here, not a repost of someone else's post that describes one aspect of your assertion. It's no one's responsibility here to disprove your assertion, it's yours alone to prove it and the rules clearly state it. Do not think you can simply come here and play by whatever rules you like. Get busy posting some supporting science."

 

Well you won't get it, not yet anyway. Your expectations of, and demands for, detailed proof of anything is beyond the scope of the discussion. This is a thought experiment (which I've mentioned several times now). Casual assertions can be made or challenged anytime about the common knowledge general principle(s) involved....

 

Wikipedia - "A thought experiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences. Given the structure of the experiment, it may or may not be possible to actually perform it, and, in the case that it is possible for it to be performed, there need be no intention of any kind to actually perform the experiment in question. The common goal of a thought experiment is to explore the potential

consequences of the principle(s) in question."

 

See? It's all about the general principle(s) in a thought experiment.... It's not about detailed mathematical proof or evidence, or whether one of the diagrams looks like a barometer, or capillary action, or cohesive forces, or how sensitive the system is to the balance of forces, or deciding if it's more like balancing a brick on its end or standing a razor blade on its edge, or viscosity, or the myriad of other engineering issues.... It's the general principle(s) of the siphon and magnetism being explored and discussed, that's all it is, an informal discussion. So you can demand all the detailed mathematical proof you want to but the previously/repeatedly stated parameters of the discussion as a thought experiment don't require me to answer any of them, even if they directly address the general principles being discussed, and you're free to do the same.

 

I'll just update you on the current status of the thread from my point of view (with the thought experiment perspective in mind). I presented a theory about how the principle of the siphon and the principle of magnetism might be combined to form a novel hypothetical arrangement, so there are really only two relevant general principles to be addressed in the thought experiment....

 

1. The siphon.... Does the diagram show a siphon that could reasonably be expected to operate normally? CraigD, who seems to have successfully grokked the intent of the thread, essentially recognized the diagram as a sound graphical representation of a siphon of normal configuration and showed how and why the forces at play would cause the movement of fluid (in post 22) saying....

 

CraigD "So fluid will flow from the right end of the tube to the left end. Because the tube is higher in places than the water surface, this is called a siphon. As long as there’s a height difference, there will continue to be pressure, and right-to-left flow."

 

We agree on that and so there's really nothing more to say about it (unless you'd like to add something).

 

2. The magnetism.... Would the permanent magnet (a stationary static magnetic field) actually have to do work on the system to maintain the depression on the surface of the diamagnetic fluid in the resevoir? In the same post as the one where he essentially recognizes the diagram as a sound graphical representation of a siphon, he goes on to say that....

 

CraigD "....no matter how it’s done – magnetics, a downward air jet, a simple dam between the left and right sides of reservoir, etc. – mechanical work must be done to keep the surface of the water near the left end of the tube lower than near the right end. It won’t stay in that condition without work...."

 

On this we disagree, so I challenged him on it saying (among other things)....

 

Aemilius "A force must move an object to do work on it right? For example, my refrigerator magnet's force isn't moving anything, and it does no work on anything. By the same token, the magnet causing the depression on the surface of the diamagnetic fluid in the resevoir doesn't move anything, and it does no work on anything."

 

So, like a friendly game of chess, it's CraigD's move now to explain, if he can, how and why he thinks the permanent magnet (a stationary static magnetic field) could be seen as doing any kind of work on this system, or, barring that, how and why some other force would be required to do work on the system for it to operate normally. Whether or not the discussion continues depends entirely on his next move, if any.

 

My feeling is that if he concedes that the permanent magnet does no work, as I contend, then he must find some other force that would be required to do work on the system for it to operate normally or my theory stands.... If, on the other hand, he can show how the permanent magnet (a stationary static magnetic field) would be doing work on the system, or that some other force would be required to do work on the system for it to operate normally my theory falls.... it's just as simple as that.

 

C1ay "Personal attacks and insults against other members WILL NOT BE TOLERATED. You have been warned. I'd advise you read the rules here."

 

A thousand apologies are yours! I'm pretty sure Moontanman recognized that remark for what it was.... a humorous quip. We've traded several in the past and I'm sure we'll trade several more in the future, though from now on I'll be sure to get your permission first!

 

So that's it.... unless you have something more you'd like to try and smack me around about. By the way, why are you the only one jumping up and down about all this kind of stuff?

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I think the best way to understand this thought experiment is to purposefully avoid the details of how its critical “water dimple” is made, simply assuming it can be done, and consider the essential mechanics of the system. We can do this in a simplified, but precise and correct, way.

 

Let’s begin with the system in the state sketched.

 

Let’s assume the size and difference in height of the surface on the right side and the bottom of the tube (which determine the force acting on the water in the tube) and the frictional forces in the tube are exactly sufficient for its rate of flow to be 1 m3/s.

 

So, after 1 s of operation, the dimple will contain 1 m3/s. of water

 

Now for the dimple to retain its shape, whatever is producing it must exert sufficient force over sufficient distance to displace some or all of the water below that 1 m3/s. of water of water to restore the dimple to its previous shape. This force, times the distance over which it acts, is the amount of work the system must performs in 1 second – that is, it is its power.

 

For the same of being able to use specific quantities in this example, let’s assume that the cross sectional area of the tube is 1 m2, the difference in height of the surface on the right side and the bottom of the tube is 1 m, and, to keep our numbers short and simple, that the acceleration of gravity is exactly 9.8 m/s/s, , and the density of the fluid (let’s just assume it’s pure water) 1000 kg/m3. The system, then, has moved a 1000 kg volume of water a height of 1 m in 1 s, so its power, [imath]m \cdot g \cdot h / t = 980 \,\mbox{W}[/imath], plus the power to overcome its friction (which is too hard to calculate, and only distracts from this discussion).

 

If less than this power is put into the system, the dimple will fill with water until the tube’s height difference is zero, and the siphon will stop.

 

The key point where this description doesn’t match yours, Aemilius, is where you state:

a 5 Tesla permanent magnet will "stay on" for a very, very long time. I'm also saying that once installed, the permanent magnet (static magnetic field) would act indefinitely to maintain the depression on the surface of the fluid in the resevoir without doing any work on the system.

I think the trouble come from you introducing the intuitive, common-sense concept “maintain”, bringing with it the assumption that maintaining a thing, like a dimple in water, requires no energy (the potential to perform work). This concept and assumption doesn’t “play by the rules” of classical physics – that is, they aren’t in its allowed vocabulary, which begins with only the fundamental quantities Distance, Mass, and Time. If you rework the concept of “maintaining” the dimple in the terms and rules of classical physics, as I have above, you’ll discover the “maintaining doesn’t require doing work” assumption is false, by calculating the minimum amount of work (not the precise, because I avoided the complicated calculations involving friction, but they’re not needed, as we only need to show the quantity is greater than zero, not precisely calculate it) “maintaining the dimple” (which all call “retaining its shape”) requires.

 

As I stated in the start of this post, I think it’s best to put out or our minds the complicated affair of how the dimple is formed, and keep in mind the basic mechanical rule that, no matter what system performs the same mechanical work, that work is the same, as defined by simple definition such as the [imath]m g h[/imath] for gravitational potential energy I used above. Magnetic fields, air jets, or flying nanoscopic robot tankers, it doesn’t matter – they must use at least energy equal to the mechanical work, plus their frictional losses.

 

Trouble may also come from including in the phrase “static magnetic field”, perhaps with the assumption that its a requirement of the presence of a permanent magnet. Because we often describe magnetic fields as a collection the force they would exert on imaginary, arbitrarily small charged test particles, it’s easy to assume that the paradox of a unchanging magnetic field that does work – exerts a force on charged particles while moving them a distance in the direction given by magnetic field lines – is a real paradox. It’s not: when real particles are substituted for imaginary test ones, magnetic fields change as they move them, and energy is required by the system. In the case of permanent magnets, the energy usually comes from the kinetic energy of the particles themselves: as they enter the strong part of the magnetic field, they deform it, they are then forced in a direction with vector components opposite their velocity, and the magnetic field returns to its “static” shape. In such interactions, the magnetic fields produces by permanent magnets aren’t unchanging, or “static”.

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