Denspressure vs Reality

I explained every one but you totally ignored them and went into a rant.
I can't help it if you rant on and refuse to grasp what I'm telling you.

No you didn't.
You made up excuses then claimed you had already explained them.
I pointed out why the closest you had come to an explanation didn't work.
That isn't a rant.

You choose anything you like and we will deal with it before we move on.
One question and one answer.
If that answer is not enough ask me to elaborate but keep to the initial question.
I'll happily elaborate on one question at a time.
If I can't elaborate any more and you refuse or cannot grasp it, then the discussion ceases and that's that for that question.

Really? So if it gets to the point where you just baselessly things and can't justify it the discussion ceases, no admission that your model doesn't work?
That hardly seems like a fair discussion.

but fine, lets try:

I have a glass dish.
Attached to this dish (at the bottom) is a flexible tube, which is then attached to a rigid glass tube 1m long.

Initially, this is all vertical so you have:
DISH
Flex Tube
Gladd Tube

I pour in mercury to fill it up to half way up the dish. There are no visible air bubbles anywhere.
Why does the mercury get pushed to the bottom of the tube?

Quote from: Edge_Loop on December 04, 2017, 12:48:05 AM

Quote from: sceptimatic on December 04, 2017, 12:32:49 AM

Quote from: Edge_Loop on December 04, 2017, 12:12:45 AM

Quote from: sceptimatic on December 03, 2017, 11:59:27 PM

Quote from: Edge_Loop on December 03, 2017, 11:52:04 PM

This thread is a jumble of one line come backs and rants, I have not noticed any experiments described (not that there aren't any, but if there are they are swamped by the bulshit on here).

If there are experiments we can try then why did you just divert when people asked you to describe experiments they could try for themselves?

I agree it's a mess.
Maybe I should be answering questions without debate.
Someone mentioned it before I think.

I did (and possibly others). If you want to describe your idea exclusively to those that agree with it (and the way you present your idea and your own admission show this to be the case) then it being presented on a forum dedicated to debate is probably not the right approach.

Maybe but then again I didn't start the topic and the topic states "denpressure vs reality" so does that mean we debate what reality is supposed to be but leave out everything that isn't mainstreams ideals of what reality is?

We might as well not debate anything then, right?
There has to be a right and a wrong in a debate but knowing a right and a wrong for everyone kills a debate stone dead because it becomes undebatable.
Arguing what is right and wrong is where debates are.

A debate on who's cat is the blackest.
Mainstream says their cat is the blackest and a true black. I disagree and think my cat is.
Mainstream scientists come up with a blackcatometer to prove how pure their black cat is and show me a picture of their black cats fur under this tool.
I ask to see it but find out it's a secret or I'm not authorised.

Now I'm told to prove mine.
I have my own eyes and a microscope. No good and I should not be debating because I have no proof.
Bingo, game over because the deck will never be stacked in my favour.
What do I have left to rely on?
The individual inquisitive minds of those that are not convinced of a fair deal. How many come forward to vent that?
Very few because most people know it's best to just accept the stacked deck even if they know it's not a proof.
Quietly they can question and they probably do.


So, although I do agree that my denpressure would be better in a place where questions can be asked of it and I can answer, it would have to be strictly moderated so it didn't become a debate or a tit for tat fest of arguing.
In the meantime when topics are put up to bait and debate, I'll stand my ground regardless of mass intent to bully me out of it.

I have not seen a single post here that isn't flawed and based on bias and belief rather than evidence and proof.

At this point no one occupies the higher ground.

And I suppose you have some evidence for your somewhat sweeping statement?

No, that was clearly hyperbole to forwards the opinion I was expressing to Scepti regarding this thread getting OTT and unproductive.

Quote from: sceptimatic on December 04, 2017, 01:39:57 AM

You choose anything you like and we will deal with it before we move on.
One question and one answer.
If that answer is not enough ask me to elaborate but keep to the initial question.
I'll happily elaborate on one question at a time.
If I can't elaborate any more and you refuse or cannot grasp it, then the discussion ceases and that's that for that question.

Really? So if it gets to the point where you just baselessly things and can't justify it the discussion ceases, no admission that your model doesn't work?
That hardly seems like a fair discussion.

but fine, lets try:

I have a glass dish.
Attached to this dish (at the bottom) is a flexible tube, which is then attached to a rigid glass tube 1m long.

Initially, this is all vertical so you have:
DISH
Flex Tube
Gladd Tube

I pour in mercury to fill it up to half way up the dish. There are no visible air bubbles anywhere.
Why does the mercury get pushed to the bottom of the tube?

I'm not quite sure what you're saying.
Can you make it clearer?

Quote from: Nightsky on December 04, 2017, 12:42:24 AM

World manufacturing is wrong and sponge Bob no pants is right!
Let me tell you, you are a hypocritical joke of a man.
Why?
Because of how you contradict your own words and how you constantly refuse to tell us about how you observed your magical molecules!

Dance about all you want weakling but the reality is, it's all low pressure we are dealing with, with your so called vacuums.

Low pressure has been explained perfectly well by me.
Now either try and understand it from my side or use your  mind to explain your side without the aid of pictures and ready plated up writings.

Liar liar sponge ball pants on fire. Show me where you have explained how you observed your magic molecules.....and dont say with a shop bought microscope!
You have no idea the equipment required to see molecules do you?
That’s why you are a dishonest liar. You have never seen molecules magic or otherwise.
It’s all just in your imagination.

I'm not quite sure what you're saying.
Can you make it clearer?

I have a dish with a hole at the bottom, somewhat like a funnel.
Attached to that, I have a flexible piece of tubing (important for later).
Attached to that I have a piece of glass tubing with one end closed.

A very much not to scale cross section would look something like this:


So why does the mercury stay at the bottom, rather than say rise to the top of the container, or have an air gap at the end?

Quote from: sceptimatic on December 04, 2017, 04:06:04 AM

I'm not quite sure what you're saying.
Can you make it clearer?

I have a dish with a hole at the bottom, somewhat like a funnel.
Attached to that, I have a flexible piece of tubing (important for later).
Attached to that I have a piece of glass tubing with one end closed.

A very much not to scale cross section would look something like this:


So why does the mercury stay at the bottom, rather than say rise to the top of the container, or have an air gap at the end?

By the way is tenacious your middle name?

I know you all hate those letters NASA, and imagine they are the Devil’s spawn, but they do have some cool stuff like the biggest vacuum chamber in the world.
https://www.nasa.gov/multimedia/imagegallery/image_feature_1281.html

It’s been shown before, and refuted by some people but it’s worth a re-run while ‘sponge ball no pants’ looks for his mysterious molecules. I know he will hate this as will every flat earth believer who wil scrabble around making up all sorts of excuses and inventing a slew of shill inspired CGI and conspiracy claims. Enjoy.

What’s really ironic is mr Sponge ball no pants, puts great virtue in ‘seeing is believing’...so see and believe. It’s a two for one as is shows a near perfect vacuum here on earth and proves gravity.

Quote from: sceptimatic on December 04, 2017, 04:06:04 AM

I'm not quite sure what you're saying.
Can you make it clearer?

I have a dish with a hole at the bottom, somewhat like a funnel.
Attached to that, I have a flexible piece of tubing (important for later).
Attached to that I have a piece of glass tubing with one end closed.

A very much not to scale cross section would look something like this:


So why does the mercury stay at the bottom, rather than say rise to the top of the container, or have an air gap at the end?

The mercury is more dense than the atmosphere and so, it displaces that atmosphere.
There's no air bubble in the tube because the mercury  in it has taken up the space the air was in.

I know you all hate those letters NASA, and imagine they are the Devil’s spawn, but they do have some cool stuff like the biggest vacuum chamber in the world.
https://www.nasa.gov/multimedia/imagegallery/image_feature_1281.html

It’s been shown before, and refuted by some people but it’s worth a re-run while ‘sponge ball no pants’ looks for his mysterious molecules. I know he will hate this as will every flat earth believer who wil scrabble around making up all sorts of excuses and inventing a slew of shill inspired CGI and conspiracy claims. Enjoy.

What’s really ironic is mr Sponge ball no pants, puts great virtue in ‘seeing is believing’...so see and believe. It’s a two for one as is shows a near perfect vacuum here on earth and proves gravity.

And this is why you'll always be naive.

The mercury is more dense than the atmosphere and so, it displaces that atmosphere.

If it was sitting up higher it would still be displacing the atmosphere.
So why does it displace the atmosphere at the bottom rather than the top, or somewhere else?

Quote from: sceptimatic on December 04, 2017, 11:48:49 PM

The mercury is more dense than the atmosphere and so, it displaces that atmosphere.

If it was sitting up higher it would still be displacing the atmosphere.
So why does it displace the atmosphere at the bottom rather than the top, or somewhere else?

It does displace it at the top. What do you think is acting on the mercury in the dish?
The mercury in the dish and in the tube is more dense than the atmosphere it displaces so  if you haven't trapped any in the tube it will be displaced.
And I can see by your tube that you didn't trap any atmosphere as it's full.

If you were to trap some atmosphere in that tube it would be very compressed by the mercury's displacement of the atmosphere above it all.

Quote from: JackBlack on December 04, 2017, 11:54:43 PM

Quote from: sceptimatic on December 04, 2017, 11:48:49 PM

The mercury is more dense than the atmosphere and so, it displaces that atmosphere.

If it was sitting up higher it would still be displacing the atmosphere.
So why does it displace the atmosphere at the bottom rather than the top, or somewhere else?

It does displace it at the top. What do you think is acting on the mercury in the dish?
The mercury in the dish and in the tube is more dense than the atmosphere it displaces so  if you haven't trapped any in the tube it will be displaced.
And I can see by your tube that you didn't trap any atmosphere as it's full.

If you were to trap some atmosphere in that tube it would be very compressed by the mercury's displacement of the atmosphere above it all.

It’s over chum, why not admit it you lost.
Other than an amusing analogy involving spongy balls which, though it did raise a titter or two, did nothing to prove your ideas. You go onabout how important seeing with your own eyes is. The vacuum facility in the USA is a giant concrete aluminium construction, which to me looks pretty real. You could solve your problem by taking a trip there and seeing for yourself rather than having to make stuff up.
Let’s face facts you will never see your magic molecules no matter how hard you look nor prove your ideas using analogies regardless of the number of sponge balls you dream up.

It’s over chum, why not admit it you lost.
Other than an amusing analogy involving spongy balls which, though it did raise a titter or two, did nothing to prove your ideas. You go onabout how important seeing with your own eyes is. The vacuum facility in the USA is a giant concrete aluminium construction, which to me looks pretty real. You could solve your problem by taking a trip there and seeing for yourself rather than having to make stuff up.
Let’s face facts you will never see your magic molecules no matter how hard you look nor prove your ideas using analogies regardless of the number of sponge balls you dream up.

I'll pretend you never said, chum.
Your naivety shows up like a beacon and now I realise why you'll always be weak.
Carry on coming out with what you do but unfortunately I can't play along with you because it takes up time and gains nothing.

It does displace it at the top. What do you think is acting on the mercury in the dish?

Displacing doesn't act on the mercury.

Perhaps this example will help:

Here you have the same volume of mercury displacing the same volume of air, but this doesn't happen. Why?

If you like I can start another line of inquiry instead.

Quote from: Nightsky on December 05, 2017, 12:22:47 AM

It’s over chum, why not admit it you lost.
Other than an amusing analogy involving spongy balls which, though it did raise a titter or two, did nothing to prove your ideas. You go onabout how important seeing with your own eyes is. The vacuum facility in the USA is a giant concrete aluminium construction, which to me looks pretty real. You could solve your problem by taking a trip there and seeing for yourself rather than having to make stuff up.
Let’s face facts you will never see your magic molecules no matter how hard you look nor prove your ideas using analogies regardless of the number of sponge balls you dream up.

I'll pretend you never said, chum.
Your naivety shows up like a beacon and now I realise why you'll always be weak.
Carry on coming out with what you do but unfortunately I can't play along with you because it takes up time and gains nothing.

No harm in loosing....think about it this way, it’s the taking part that counts.
I can well understand why you dont want to, as you put it ‘play’ a game you will never win.
As long as you stick with you denpressure ideas you will forever be a looser, just remember that.
May I take this opportunity to remind you of some good words by someone you may know.

“Too many people live on too many stories without any physical proof to the stories”

While I can offer you a structure made from concrete and aluminium, the best you can do is an idea made from sponge balls. Think on that mr Sponge ball no pants.

By the way you can call me Gwyneth.

Quote from: sceptimatic on December 05, 2017, 12:01:57 AM

It does displace it at the top. What do you think is acting on the mercury in the dish?

Displacing doesn't act on the mercury.

Perhaps this example will help:

Here you have the same volume of mercury displacing the same volume of air, but this doesn't happen. Why?

If you like I can start another line of inquiry instead.

The atmosphere you displaced by the mercury doesn't all just decide to descend onto the mercury in one immediate dense batch like you're showing.
The atmosphere that's displaced by the mercury takes its place in the entire stack and compresses it a little more against a lot less because it's now unequal pressure back onto the air displaced at the bottom of the tube until that air is squeezed out by compression of upper atmosphere back onto the mercury that squeezes the atmosphere from the tube because it's less dense than  the mercury and atmosphere above.

This leaves a full tube like you shown but the volume of air displaced by showing the cut out mercury is not how it works.


This is why I used the swimming pool analogy to you and I'll explain it again using this drawing of yours, so get your thinking cap on.

Imagine the mercury is in a swimming pool and that swimming pool is the atmosphere.
Your mercury experiment is at the bottom of the pool as if it were land.

Ok?


Ok before you fill the tube and the dish with mercury you see that it's filled with water (atmosphere for instance) so now you pour in your mercury and as you do so you see that the water (air) is being forced out.
The reason this is happening is because not only is the mercury dense in forcing it out but the water in the actual pool is also being displaced by the mercury itself and that water is compressing back onto that mercury and displacing the water inside the tube and dish by the mercury's own dense displacement of that water.

Once that water is all squeezed out and replaced by the mercury then that water is dispersed into the entire pool and is merely added to that pools mass whilst all that pools mass is overall sitting on the dense mass in that water but the mercury itself is only displacing it's own dense mass of it.

Can you see what I'm saying now?

Quote from: sceptimatic on December 05, 2017, 12:25:38 AM

Quote from: Nightsky on December 05, 2017, 12:22:47 AM

It’s over chum, why not admit it you lost.
Other than an amusing analogy involving spongy balls which, though it did raise a titter or two, did nothing to prove your ideas. You go onabout how important seeing with your own eyes is. The vacuum facility in the USA is a giant concrete aluminium construction, which to me looks pretty real. You could solve your problem by taking a trip there and seeing for yourself rather than having to make stuff up.
Let’s face facts you will never see your magic molecules no matter how hard you look nor prove your ideas using analogies regardless of the number of sponge balls you dream up.

I'll pretend you never said, chum.
Your naivety shows up like a beacon and now I realise why you'll always be weak.
Carry on coming out with what you do but unfortunately I can't play along with you because it takes up time and gains nothing.

No harm in loosing....think about it this way, it’s the taking part that counts.
I can well understand why you dont want to, as you put it ‘play’ a game you will never win.
As long as you stick with you denpressure ideas you will forever be a looser, just remember that.
May I take this opportunity to remind you of some good words by someone you may know.

“Too many people live on too many stories without any physical proof to the stories”

While I can offer you a structure made from concrete and aluminium, the best you can do is an idea made from sponge balls. Think on that mr Sponge ball no pants.

By the way you can call me Gwyneth.

Until you come back with something worthwhile, I'll bid you farewell.

Can you see what I'm saying now?

It still doesn't make sense, but I will move on:
I now rotate the tube to try to get something like this:

But instead of getting that, I end up with this:

Without any air from the top of the dish travelling into the tube.
Why?

Quote from: sceptimatic on December 05, 2017, 12:47:00 AM

Can you see what I'm saying now?

It still doesn't make sense, but I will move on:
I now rotate the tube to try to get something like this:

But instead of getting that, I end up with this:

Without any air from the top of the dish travelling into the tube.
Why?

I believe I already know what the answer will be...

Quote from: sceptimatic on December 05, 2017, 12:47:00 AM

Can you see what I'm saying now?

It still doesn't make sense, but I will move on:
I now rotate the tube to try to get something like this:

But instead of getting that, I end up with this:

Without any air from the top of the dish travelling into the tube.
Why?

I guessed this is what you were coming to.

Keep your mind back on the swimming pool analogy and if anyone else (Jane?) can grasp what I'm saying then feel free to chirp in.


If we were to fill this like you show, with mercury in that same swimming pool to look like what you show then that's how it would stay, because the mercury would be displacing the water (atmosphere) as it stands, which means you do not have a barometer, at all.
You nullify the whole purpose of it.


Why do you think they have a gap in the tube?

You see, if you done that in the pool then the water that's displaced by all of the mercury will stay displaced because there's no give in the force upon the mercury in the dish and also in the tube, as it's full and without any water (air) at the top to compress and allow to decompress upon pressure change of the water (assuming we use the water to air analogy).


Can you see what I'm saying?

If we were to fill this like you show, with mercury in that same swimming pool to look like what you show then that's how it would stay, because the mercury would be displacing the water (atmosphere) as it stands, which means you do not have a barometer, at all.

Nope. It still works, it just reads a higher pressure due to the weight of the water.

Why do you think they have a gap in the tube?

What gap?
The tube is solid, the only gap is to the dish to allow it to equilibrate with the mercury in the dish.
Or do you mean the void at the top?
I have already explained it with mainstream science, if you like I can do so again, but why not focus on your model?

You see, if you done that in the pool then the water that's displaced by all of the mercury will stay displaced because there's no give in the force upon the mercury in the dish and also in the tube, as it's full and without any water (air) at the top to compress and allow to decompress upon pressure change of the water (assuming we use the water to air analogy).
Can you see what I'm saying?

Yes, the problem is that would apply in the air as well.
The air displaced by the mercury would stay displaced as there's no give in the force upon the mercury in the dish and also in the tube, as it's full and without any air at the top to compress and allow to decompress.

But that doesn't happen. Instead you get a void at the top.

Quote from: sceptimatic on December 05, 2017, 01:19:19 AM

If we were to fill this like you show, with mercury in that same swimming pool to look like what you show then that's how it would stay, because the mercury would be displacing the water (atmosphere) as it stands, which means you do not have a barometer, at all.

Nope. It still works, it just reads a higher pressure due to the weight of the water.

How can it read a higher pressure when the tube is full of mercury?
How can there be a reading, at all?

Quote from: sceptimatic on December 05, 2017, 01:19:19 AM

Why do you think they have a gap in the tube?

What gap?
The tube is solid, the only gap is to the dish to allow it to equilibrate with the mercury in the dish.
Or do you mean the void at the top?

I mean the atmospheric void at the top.

I have already explained it with mainstream science, if you like I can do so again, but why not focus on your model?

Explain it again nice and simple and explain how whatever you're about to explain actually happens.

Quote from: sceptimatic on December 05, 2017, 01:19:19 AM

You see, if you done that in the pool then the water that's displaced by all of the mercury will stay displaced because there's no give in the force upon the mercury in the dish and also in the tube, as it's full and without any water (air) at the top to compress and allow to decompress upon pressure change of the water (assuming we use the water to air analogy).
Can you see what I'm saying?

Yes, the problem is that would apply in the air as well.
The air displaced by the mercury would stay displaced as there's no give in the force upon the mercury in the dish and also in the tube, as it's full and without any air at the top to compress and allow to decompress.

But that doesn't happen. Instead you get a void at the top.

You only get a void at the top if you allow it. If you do not allow it you will never get a void.
It has to be a measure of atmosphere, enough to be allowed to compress and obviously decompress.
I'll be happy to keep on explaining this until you get it.

Quote from: Nightsky on December 05, 2017, 12:41:16 AM

Quote from: sceptimatic on December 05, 2017, 12:25:38 AM

Quote from: Nightsky on December 05, 2017, 12:22:47 AM

It’s over chum, why not admit it you lost.
Other than an amusing analogy involving spongy balls which, though it did raise a titter or two, did nothing to prove your ideas. You go onabout how important seeing with your own eyes is. The vacuum facility in the USA is a giant concrete aluminium construction, which to me looks pretty real. You could solve your problem by taking a trip there and seeing for yourself rather than having to make stuff up.
Let’s face facts you will never see your magic molecules no matter how hard you look nor prove your ideas using analogies regardless of the number of sponge balls you dream up.

I'll pretend you never said, chum.
Your naivety shows up like a beacon and now I realise why you'll always be weak.
Carry on coming out with what you do but unfortunately I can't play along with you because it takes up time and gains nothing.

No harm in loosing....think about it this way, it’s the taking part that counts.
I can well understand why you dont want to, as you put it ‘play’ a game you will never win.
As long as you stick with you denpressure ideas you will forever be a looser, just remember that.
May I take this opportunity to remind you of some good words by someone you may know.

“Too many people live on too many stories without any physical proof to the stories”

While I can offer you a structure made from concrete and aluminium, the best you can do is an idea made from sponge balls. Think on that mr Sponge ball no pants.

By the way you can call me Gwyneth.

Until you come back with something worthwhile, I'll bid you farewell.

So I take it it’s an admission of defeat and a no show on your magic imaginary molecules.

How can it read a higher pressure when the tube is full of mercury?
How can there be a reading, at all?

That's the point, it isn't. There is still a void at the top. The mercury drops down to a height based upon the pressure outside. It doesn't matter if outside is air, water, some other gas/fluid or a vacuum. All that does is change the pressure and thus the height.
The only exception is if you use a fluid filled barometer and submersed it in a bath of a fluid which is denser.
So you wouldn't be able to use a water filled barometer with it submerged in mercury.

I mean the atmospheric void at the top.

Why atmospheric? you have already indicated there was no air there.

Quote from: JackBlack on December 05, 2017, 01:25:31 AM

I have already explained it with mainstream science, if you like I can do so again, but why not focus on your model?

Explain it again nice and simple and explain how whatever you're about to explain actually happens.

Okay then:
When the tube is inverted the weight of the mercury pulls it down. This is a result of gravity, where the large mass of Earth attracts the mass of the mercury.
So this weight starts to pull the mercury down towards Earth and away from the top of the tube.
But as soon as it moves down, even just a tiny bit, there is a void behind it.
This results in a pressure differential with the atmosphere (or water) outside the dish pushing down on the mercury surface of the dish and thus up on the column against the weight of the mercury.
The mercury continues to drop until this reaches a balance with the pressure due to the weight of the mercury equal to the pressure differential.

Is that enough or do you need more explained?

You only get a void at the top if you allow it. If you do not allow it you will never get a void.

Nope. You get the void at the top as long as the tube is long enough.
I have done it several times, and a flexible tube can make it a lot easier.
When done properly, the only thing in the tube is that mercury. There is no time that any air bubble goes in the tube which can rise to the top. Yet the void still appears.
Again, the same can be done under water. No atmosphere in the void, no water in the void.


Another setup which can really help ensure no air can get in is to have a tap at the top of the dish and the top of the tube.
You fill it up, starting with both taps open to get a lot in the dish, then closing the tap at the dish, then filling it past the tap at the top of the tube.
Then you close the tap at the top, and no air is there. Open the tap at the dish and you get the void at the top of the tube (below the tap).

It has to be a measure of atmosphere, enough to be allowed to compress and obviously decompress.
I'll be happy to keep on explaining this until you get it.

I don't want you to just keep on asserting things. I want you to explain what occurs in reality using your model.

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

How can it read a higher pressure when the tube is full of mercury?
How can there be a reading, at all?

That's the point, it isn't. There is still a void at the top. The mercury drops down to a height based upon the pressure outside. It doesn't matter if outside is air, water, some other gas/fluid or a vacuum. All that does is change the pressure and thus the height.
The only exception is if you use a fluid filled barometer and submersed it in a bath of a fluid which is denser.
So you wouldn't be able to use a water filled barometer with it submerged in mercury.

The mercury cannot drop if there's nothing to make it drop.
This is the entire point of atmosphere inside the tube.
Think of it as a spring if you want to but there has to be atmosphere left in the tube.

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

I mean the atmospheric void at the top.

Why atmospheric? you have already indicated there was no air there.

Yes but in indicating there was no air there I was also indicating why there would be no barometer to work to measure anything.
All you're doing is mixing yourself up.

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

Quote from: JackBlack on December 05, 2017, 01:25:31 AM

I have already explained it with mainstream science, if you like I can do so again, but why not focus on your model?

Explain it again nice and simple and explain how whatever you're about to explain actually happens.

Okay then:
When the tube is inverted the weight of the mercury pulls it down. This is a result of gravity, where the large mass of Earth attracts the mass of the mercury.
So this weight starts to pull the mercury down towards Earth and away from the top of the tube.
But as soon as it moves down, even just a tiny bit, there is a void behind it.
This results in a pressure differential with the atmosphere (or water) outside the dish pushing down on the mercury surface of the dish and thus up on the column against the weight of the mercury.
The mercury continues to drop until this reaches a balance with the pressure due to the weight of the mercury equal to the pressure differential.

Is that enough or do you need more explained?

The weight of the mercury cannot pull anything down in your full scenario. There's no pull for starters but there's also no decompression inside the tube to create any movement, at all.

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

You only get a void at the top if you allow it. If you do not allow it you will never get a void.

Nope. You get the void at the top as long as the tube is long enough.
I have done it several times, and a flexible tube can make it a lot easier.
When done properly, the only thing in the tube is that mercury. There is no time that any air bubble goes in the tube which can rise to the top. Yet the void still appears.

It's got nothing to do with being long enough. It's all to do with the tube having atmosphere trapped in it for it to even work at all.

Again, the same can be done under water. No atmosphere in the void, no water in the void.

If there's no atmosphere in the void then there's no void.

Another setup which can really help ensure no air can get in is to have a tap at the top of the dish and the top of the tube.
You fill it up, starting with both taps open to get a lot in the dish, then closing the tap at the dish, then filling it past the tap at the top of the tube.
Then you close the tap at the top, and no air is there. Open the tap at the dish and you get the void at the top of the tube (below the tap).

You can do that but then you lose the whole point of having a barometer. This is what I'm trying to tell you because the barometer works of displacement of atmosphere by whatever pressure it displaces at any given time, measureable on a printed gauge on the tube.

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

It has to be a measure of atmosphere, enough to be allowed to compress and obviously decompress.
I'll be happy to keep on explaining this until you get it.

I don't want you to just keep on asserting things. I want you to explain what occurs in reality using your model.

That's what I'm doing but you're trying to scupper it.

Quote from: JackBlack on December 05, 2017, 02:54:12 AM

Quote from: sceptimatic on December 05, 2017, 01:32:14 AM

You only get a void at the top if you allow it. If you do not allow it you will never get a void.

Nope. You get the void at the top as long as the tube is long enough.
I have done it several times, and a flexible tube can make it a lot easier.
When done properly, the only thing in the tube is that mercury. There is no time that any air bubble goes in the tube which can rise to the top. Yet the void still appears.

It's got nothing to do with being long enough. It's all to do with the tube having atmosphere trapped in it for it to even work at all.

So according to denpressure the atmosphere could support a column of mercury of any height? Over one metre, say? Is that correct?

Have you ever seen this happen?

So we’ve gone from arguing about the existance of vacuum to disputing how a simple barometer works. It’s obvious how it works no debate required.

I’m nominating Jack Black for a medal In patience and perseverance.

However just to clarify a few things regarding how a barometer works. I wouldn’t  want any passerby to go away with a false idea of how they actually function.
http://www.explainthatstuff.com/barometers.html

And a nice short video explaining how the mercury bath barometer actually works

Keep your mind back on the swimming pool analogy and if anyone else (Jane?) can grasp what I'm saying then feel free to chirp in.

I'd help but I've given up talking to Jackblack, you can tell by the way he formulates his argument he's just trying to look smart. It's basically an identical principle to filling a glass with water and turning it upside down, or putting a glass in a sink full of water, turning it upside down and lifting it out while noticing water doesn't stay inside it. He's not going for an informed response, he's going for an ego trip.

He's not going for an informed response, he's going for an ego trip.

Presumably you're talking about scepti here?  He's the one claiming every single engineer and scientists on the planet is completely wrong about basic physics and he's literally the only person to have ever worked how things really work.  He's the one saying all the greatest minds of the last 300 years, from Newton through to Einstein are wrong and he's right.  I'm not really sure you can get much more egotistical than that.


You won't debate Jack because he hands your ass to you every time, that's why.