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Post by JRowe on Mar 15, 2016 8:20:33 GMT
They're good analogies for the principle they're applied to. Picking on details or applying them to different situations is doomed to failure for any analogy. There isn't an analogy in existence that can survive being picked at constantly: that's why they're analogies. They're illustrations to help understand a principle, no more. Constantly demanding that they be 100% accurate is an absurd ask. Please stop ignoring this, it's the basics of how analogies work. The analogues aren't wrong, they're analogies. They act exactly as analogies are meant to. Don't hold them to ridiculous standards. The analogy of spacetime as a blanket under relativity is hardly accurate, it has very little in common with an actual blanket, but it's a good illustration of the one principle being explained. That's all it's meant to be. No one expects analogies to be a completely accurate depiction. The fact you're focusing exclusively on the analogies meant to illustrate the law, rather than targeting the underlying explanation illustrated by it, should make it clear that the actual model is fine.
Air, like water, exerts friction. And air doesn't flow to the vacuum above the Earth because an external force is at play (moving everything down to the Earth's surface), and it's already been pointed out what effect external influences have.
Stop ignoring everything I say. I have already explained the countless issues with using heat as a reliable analogue for the principle under question.
If you take away the external force, what happens depends on the object. Water has surface tension, so there's still a force at play: gravity is essentially a balance, overcoming the force already acting on it. if you put gas into a vacuum, however, it's pretty clear it will expand out and won't stay the exact same volume, as you're claiming it would in the absence of force.
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Post by Nikki on Mar 15, 2016 15:03:11 GMT
There are good analogies and bad ones. You admitted in your first response that water was not a good example since what you described wouldn't work in zero gravity or without a container. In zero gravity surface tension would bring a small and big blob of water together if they touched but like you said it's because of another external force. So clearly this is not a universal law.
You said that for that reason gases might be a better example. As much as you'd like gasses also don't act that way in all situations. They move only if there is external force or energy acting. If you create vacuum in a container here on earth and then open it air will rush in mostly because of all the pressure of the air above it created by its weight i.e. gravity. You also didn't explain why a deflating balloon wouldn't leave a vacuum behind.
From Newton's laws of motion we know that objects will stay stationary or in constant motion unless there are forces working on it.
Consider these case scenarios and please tell me what would happen in each and why:
we have a single molecule of oxygen at rest in the middle of vacuum - will it move?
we have two molecules at rest lets say separated by 1 mm - will they move, why and where?
we have 10 molecules, each one no closer to another than 1mm - will they move, why and where?
we have 10 million molecules in the same setup - will they move, why and where?
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Post by JRowe on Mar 15, 2016 22:05:49 GMT
Once again, water is a good analogy for the example I applied it to. If you persist in applying analogies to areas they're not meant to describe, I'm not sure what it is you expect. Water was an illustration of how more than is required to fill in a low concentration will flow. Do away with the container, you'll still observe that, it's just less noticeable: it is simply ludicrous to suppose that only the precise volume necessary to level out will move, and is plainly not the case. The analogy is great. You are constantly trying to apply it to something it does not, is not meant to, and has never been meant to illustrate. How many times must I say this? Please stop ignoring every word I say. the law isn't relevant when a force, such as surface tension, acts to prevent it. I have said this multiple times. It is universally the presence of something that stops motion that prevents the law from holding. This is nothing new, it's always the case that a law can be prevented by the influence of another entity. Newton, thermodynamics... all of them presuppose the lack of interference. Newton's first law says it openly, the second law of thermodynamics relies on a closed system... Constantly relying on situations where there is a force to prevent motion very plainly does not compare. Gases exert friction. I have said this. Pressure is simply the manifestation of this law with matter: it's pretty clear that accelerating mass will exert a force.
Multiple molecules in vacuum will move to do what they can to fill in the vacuum. I suggest you look up free expansion. I am very tired of repeating myself.
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Post by Nikki on Mar 15, 2016 22:41:55 GMT
"Water was an illustration of how more than is required to fill in a low concentration will flow" - in the presence of gravity. We established that already, right? "Do away with the container, you'll still observe that, it's just less noticeable" - you will not notice any waves going back. Do you have an answer for my balloon question? "it is simply ludicrous to suppose that only the precise volume necessary to level out will move" - levels have only a meaning in the presence of gravity and containers. "the law isn't relevant when a force, such as surface tension, acts to prevent it." - you misunderstood. In vacuum nothing is preventing the water levels to equalize, also nothing is making them do so so they won't. We established that, right? I gave an example with surface tension when they still might equalize. The surface tension is going to be the force that will make the equalization possible, not prevent it.
So you predict that two molecules or more will suddenly start moving away from one another, right? Compelled why what force? When they move away do they then change direction and move back to fill the void they've just left?
In reality just the opposite happens - depending on how precise you want to be. When you have two neutral molecules motionless next to each other, they will stay motionless just like Newton's law predicts. However, the molecules have mass and they do have tiny gravitational fields so over extended period of time they will start moving towards each other. This tiny gravitational field will get more noticeable the more molecules you have so with millions of molecules the collapse will happen faster. There are millions of gas clouds out there. If they are big enough they will collapse into stars, not disperse.
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Post by JRowe on Mar 15, 2016 23:11:00 GMT
Please stop ignoring every word I say. Stop insisting analogies must be a 100% accurate depiction of every aspect of a model, stop ignoring the fact gases have friction and so your balloon example remains irrelevant as pointed out several times already, and stop relying on examples with an external force at play that would prevent a law. Once again, I refer you to free expansion: a fact you have repeatedly ignored. I am sick of having to repeat myself. You have not once addressed a single one of my points.
Let's suppose you have two boxes joined by a lone tunnel. That tunnel has a divider. Now, one box is filled with gas, one is a vacuum. Gravity is irrelevant: orient the boxes however you want. Have the filled box on the bottom, if you want. Now remove the divider. Will the gas stay where it is, or will it fill the lower concentration/vacuum? The latter, clearly. this is observed, scientific fact. Where does the force come from to do this? The answer is the same as the answer to your such question. A gas expands to fill vacuum. I don't understand why you would deny this. You cannot simply deny it when it's inconvenient for your argument.
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Post by Nikki on Mar 16, 2016 0:42:51 GMT
Maybe the problem is that you are not very clear in your explanations. I never got that you meant the friction to explain the balloon example. So the friction does not prevent the air from flowing out but it’s responsible for preventing the vacuum from forming. Do you have any details to add why that would be?
"stop relying on examples with an external force at play that would prevent a law” - I did the opposite with the water example. What I’m saying is that gravity, an external force is the only thing that makes your example work. What forces am I saying prevent water from equalizing in zero gravity?
"You have not once addressed a single one of my points. “ - which points would you like me to address?
OK, I’ll address your boxes if you address my two molecules in detail. I want to know what forces cause two molecules to disperse.
What happens in the two boxes example will depend on how much energy the gas has. If the gas has a lot of energy, meaning the molecules randomly move around, some of them will find their way through the tunnel to the other chamber. The molecules will travel from one chamber to another and back randomly but after a while you will stop noticing any difference since the same amount will flow out as will flow in. If the gas bass no energy lifting the divider will not change anything. The molecules had no energy to move with the divider and they still don’t the energy to move without it. The energy and the force it creates is the only thing that makes the expansion work.
Now, you describe the two molecules for me in a similar detail giving reasons for every move and action.
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Post by Nikki on Mar 16, 2016 13:01:20 GMT
"stop relying on examples with an external force at play that would prevent a law” - I kept thinking about this because it didn’t make sense to me. In all my examples I do the OPPOSITE. I take AWAY the forces to show that without them your ‘universal’ law stops working. Can you give me an example where I introduced forces to counteract your law?
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Post by JRowe on Mar 16, 2016 16:44:54 GMT
Gas exerts friction: the flow out of a balloon is slowed. A vacuum wouldn't form for that reason alone: all of the air can't vacate the balloon in one instant. Besides, a balloon would be the analogue of the case (bringing back the original divider/box of water analogy) of the divider only being lifted a crack: there's very little room for the air to escape, and so it does so slowly meaning any caused imbalance would be minor.
How many times must I bring up surface tension for you to acknowledge it? You're not introducing it, I never said you applied a brand new source, but the fact is all your objections rely on its presence.
Once again, I suggest you look up free expansion. All molecules possess kinetic energy, save those at absolute zero (which physically can never be reached). This kinetic energy is the source of motion. I'm not claiming to know they're exact course, but it's trivially obvious they'll ultimately end up moving away from one another. Any gas put into vacuum will spread out, in the absence of external forces.
If you want the points you have ignored, free expansion and surface tension would be the clearest examples.
Here is another illustration I would very much like you to not ignore. The closest analogue to the behaviour of aether would be if a vacuum appeared in a room full of gas. We know that the gas will fill in the vacuum: and we know that it will try to do so from all sides. If we model the vacuum as a cube, that's six sides that air will rush in from, all with the goal of filling in a low concentration, a vacuum, of the same size. More air than is needed will go in. That's the scientific basis. Intuitively, it's clear that the vacuum won't fill in with zero consequences: there'll be wind going outwards as a result. Of course, gas has friction so the analogy isn't perfect (it's an analogy: it's not meant to be) but it plainly demonstrates the principle.
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Post by Nikki on Mar 16, 2016 19:12:06 GMT
In the ballon example I didn't specify how large the opening is. It could be as large as in your water example. Water also has friction and much greater than that of gas yet in your example that doesn't prevent it from creating a deficit in one of the chambers.
I'm not clear why you keep mentioning the surface tension. Is it because you think that it prevents the water to equalize in zero gravity? Surface tension is present in every environment. It's present here on earth but it doesn't prevent the water from flowing in your example. Why would it prevent it in zero gravity? Surface tension might actually have the opposite effect from what you're saying. If you bring the two blobs of water close enough it might actually attract them and join them. Imagine mercury droplets joining. So it's far from preventing your scenario to work in zero gravity. It's the ONLY thing that will make it work. I said that before a few times.
"All molecules possess kinetic energy" - OK, we can make this energy arbitrarily small but OK. And it's precisely that energy that was introduced into the system from the outside that makes the free expansion possible. Without this energy there would be no free expansion, right? That's why I asked my question a while back - does ether posses similar kinetic energy that would enable it to expand - to which I believe you said no.
Molecules have no goals. They move wherever there is room. So in this scenario they would be moving in and out of the void or flying through it until it becomes crowded. If it becomes as crowded as the surrounding area the molecules are still going to be moving into it but the same amount will be leaving so we won't notice a difference. Like you said, gases have friction so this situation would likely create currents/wind. But I assume those are irrelevant to the analogy since ether doesn't have friction, right?
Now why are you ignoring the two molecules scenario and explanation why you think they would disperse in vacuum?
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Post by JRowe on Mar 16, 2016 21:46:49 GMT
If you're talking about a balloon, it's pretty clear how large the opening would need to be. If you propose just cutting a balloon open, then the air would rush out, but you run into the problem of this being the precise opposite situation. At no point have I said gas wouldn't create a lack, but in the small opening case no such thing would happen, and in the large opening case you're trying to alter the concentration of a huge space with a much smaller one: any rebound force would be negligible. Scale's important.
Surface tension keeps water together. It prevents it spreading. It's the different between a liquid and a gas. If you think it makes my model work, you clearly have no understanding of what I propose. An object kept together by an external force is governed by a separate force, and so generally applicable laws are irrelevant. I have no idea why you would think drops of water joining is even remotely relevant.
Why would aether need energy? It is not a mass. I see you are at last acknowledging the existence of free expansion. How then can you still deny the law of things tending towards equilibrium?
Something doesn't need to have a goal to obey a natural law. I don't understand how you can seriously deny low concentrations are filled in. You've already referred to pressure as an example: where does that come from? Why would pressure push high concentrations towards low? They flow in. Yes, gases have friction, but friction isn't required. Consider actually thinking about the model as proposed rather than doing as I have repeatedly asked you not to do and treating analogies as though they're 100% accurate. When a high concentration shifts, a low concentration is left in its wake because there is no realistic way for only the precise amount required to fill in the low concentration to move: more than is necessary flows (less, and a low concentration would be left). As a result, a low concentration is left behind, which in turn must be filled in, and the same principle applies. Friction would dampen this effect. The lack of it ensures this motion continues. Wind is simply how we observe the effect with matter: once again, stop trying to apply analogies to situations they're not meant to describe.
In what way have I ignored the two molecules situation? I generalized: gave a stronger statement. It's simply easier to understand what's happening in that situation. I'm interested in helping you understand, not in getting needlessly distracted by overanalysing analogies that are only ever meant to be analogies. I have explained on multiple occasions why gases in vacuum spread out. You have already acknowledged that free expansion exists. What more is there that needs to be said?
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Post by Nikki on Mar 16, 2016 22:36:59 GMT
"At no point have I said gas wouldn't create a lack" - so then you are saying that if the opening was large enough the balloon would deflate and then reinflate (partially?)
"Surface tension keeps water together. It prevents it spreading." - yet in your example (and everyday experience) it spreads just fine. Why does it prevent from spreading in zero gravity?
"why you would think drops of water joining is even remotely relevant" - first I didn't say drops of water. I said blobs. It's relevant because that's how one volume could join another in zero gravity.
"I see you are at last acknowledging the existence of free expansion." - I never said I didn't in gases. I always said that they expand because of the energy that they absorbed. However energetic gases expanding hardly makes it a universal law. You are trying to apply a phenomenon that makes things spread because of energy to something that doesn't have energy.
"how you can seriously deny low concentrations are filled in" - I give you numerous examples when they don't. You gave me only two - gases and heat. based on that somehow it becomes a universal law that applies to anything, even things not remotely similar to gas or heat.
"there is no realistic way for only the precise amount required to fill in" - precise how, to the atom? Of course not. Precise enough so we wouldn't notice or even measure? Of course yes.
You ignored it because you just summarized all the case scenarios I asked about that they would simply fill the void but didn't answer how. In my case scenarios the molecules are stationary. How would they fill the void, what would make them move?
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Post by JRowe on Mar 17, 2016 10:24:58 GMT
The opening would have to be so large that inflation/deflation wouldn't mean anything. And again, scale is important: please don't just ignore half my response.
How many times do I have to repeat myself? Gravity acts as a balance of sort: it acts against the surface tension. Forces may be balanced by other forces. Remove gravity, and surface tension dominates. We're not talking about any situation remotely close to how blobs of water would join. It's still utterly irrelevant. We're not talking about volumes joining anyway, we're talking about concentrations levelling out: which happens with, say, gases which have no surface tension.
A law observed universally makes it a universal law. the fact is, you've been unable to provide a single exception that hasn't been reliant on an external force interfering, which you have repeatedly been called out on.
"precise how, to the atom? Of course not. Precise enough so we wouldn't notice or even measure? Of course yes." So, you completely agree with what I'm saying, you're just arguing for the sake of it.
How would any stationary gas fill a void? No, they can't literally fill vacuum because there's not enough of them, but they would try. Free expansion, as you have already conceded, would cause them to spread. You don't get to ignore it simply because it's inconvenient for you here. Why do you believe the same principle fails to hold?
I notice you also ignore the realistic outline of the flow of aether. Things tend to equilibrium. This is scientific fact.
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Post by Nikki on Mar 17, 2016 13:38:15 GMT
"The opening would have to be so large that inflation/deflation wouldn't mean anything. And again, scale is important” - but in your water example it’s precisely a large opening that makes it work. What scale would make the balloon reinflate? Is scale curtail to your water example, what is it?
"Gravity acts as a balance of sort” - are you saying that the force of gravity is equal to surface tension? Different liquids have different surface tension. Does gravity balance each one differently?
free expansion is not a law, much less a universal one. Seriously, look it up. It only applies to gasses with an input of energy. And even with gases it’s not a law. You’re making it into a law and I’m trying to understand how it even applies since there are so many counter examples.
"you've been unable to provide a single exception that hasn't been reliant on an external force interfering” - you haven’t been able to provide a single example that wouldn’t require an external force or source of energy that results in a force.
"precise how, to the atom? Of course not. Precise enough so we wouldn't notice or even measure? Of course yes." So, you completely agree with what I'm saying, you're just arguing for the sake of it. - if by this you mean that when you say ‘a precise volume’ you mean it precise to the atom then I completely agree. A precise volume to the atom would not fill in the existing void.
"Free expansion, as you have already conceded, would cause them to spread.” - it’s clear that gas will expand when there is energy in the system. In my example the gas particles have no energy yet you claim they would gain it once confronted with vacuum. Please explain how that would happen instead of avoiding the answer.
"Why do you believe the same principle fails to hold?” - yes, the principle is wholly dependent on the amount of energy the gas has.
"Things tend to equilibrium. This is scientific fact.” - no, there is no equilibrium without a force causing it.
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Post by JRowe on Mar 17, 2016 14:23:48 GMT
In the balloon example, a small opening means the flow of pressure is smaller, the exact same as in the water example. A large opening means the flow is faster. This means the flow is faster. In the water example, the relative sizes of the inside and outside mean it's easier to observe the rebound: this isn't the case with a balloon. So, under your logic, how would air escape a balloon if there is no reason for the high concentration to flow out?
Gravity is not equal to surface tension, but it acts against the force.
Every law is only relevant in certain situations: I could provide counter examples to Newton's first law, by your logic, as acceleration clearly exists. Every single counter example you have supplied relies on a force that damps motion. This has been pointed out to you multiple times, please stop ignoring it, it is impossible to have a discussion when one person keeps avoiding every single point. Free expansion is not a law: it is the application of one. Nonetheless, it is clearly a fact.
I am not interested in absurd scenarios. it is physically impossible for a molecule to have no energy. Further, masses exert a force when they accelerate, I don't see how that's meant to be an argument. It's part of the definition of a force.
Given your only attempt at a counter example has been to suppose an impossible state of affairs, and that you are apparently complaining that Newton's second law holds, I think it's fairly clear that things do indeed tend to equilibrium.
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Post by Nikki on Mar 17, 2016 14:52:52 GMT
So let's summarize your universal law of free expansion: Generally it's supposed mean that high concentrations/densities expand into low concentrations/densities.
The law is responsible for liquids to flow and level off on earth. In zero gravity it's thwarted by the mighty surface tension. If it weren't for the surface tension liquids would still level off in zero gravity. What level that would be is however unclear since the concept of 'level' doesn't make sense in zero gravity.
The law is responsible for energetic gases to fill areas of low concentration or voids in earths gravity. On the edge of the atmosphere however the weaker gravity actually prevents the gas to expand into the vacuum. The law starts working again once we move farther out to zero gravity.
Generally dense things don't expand into the thin air because of the surface tension - except when they do.
Since we observe these things this law is clearly universal and can be applied to anything at all.
In addition it has an accompanying phenomenon when things free expand too much which is then followed by a free contraction. Even though this wasn't observed outside liquids in containers on earth this is still a universal law.
Did I get everything right?
A few follow up questions. If you take a glass container, fill it half with water and then seal it wouldn't you expect the free expansion to expand the water into the air part and equalize? For the sake of speed, please think before you start talking about gravity and surface tension.
Why do we often see the opposite happening when low density things go into high density environments like air going into water?
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