I'm debating whether I should just go right back to square one
You should. Do it one point at a time, making sure each point is clear and doesn't contradict prior points.
Ok let's take the basic barometer with the dish and mercury up the tube stance.
Oh goody. Lets see if you can provide a rational explanation this time...
Ok, as you know Mercury is used because it's a very dense liquid metal and it is very good at displacing atmosphere.
Displacing atmosphere has nothing to do with it. It is used because it is dense.
Under denspressure that should be irrelavent.
We absolutely know we cannot get a complete vacuum, regardless of people arguing that we can....on Earth.
Who is arguing we can?
We can't get a perfect vacuum, but we can get pretty darn close.
Ok, so when the tube is filled with mercury and tipped upside down to sit in the mercury filled dish, we can see that there is a void in the tube after the mercury drops, right?
We know this void is not a true vacuum, ok?
No, it isn't, but it is pretty darn close.
We know this because the tube was filled with mercury before being inverted. No air could go into the void, so that void is basically empty.
Ok, so now we have to figure out what's happening from this point on and this is where your air pressure changes come into play.
No, not just from this point on, also from before.
We need to understand what is changing between the tube being upright and the tube being inverted. If pressure was all there was to it the tube would remain the same.
Remember your water glass example, where the atmospheric pressure causes the water to remain in the glass?
The same thing should be happening here, with the atmospheric pressure forcing the mercury all the way up to the top of the glass.
If there was enough air pressure at the top, that would have been there before the tube was inverted and thus the mercury should be pushed out of the tube right from the start.
The mercury dish is displacing its own dense mass of atmosphere and that atmosphere is resisting that displacement by squeezing back or crushing back or resisting the push in to that atmosphere. Whichever way you want to look at it.
Which should thus push the mercury all the way up the tube, unless there is some force other than air pressure acting.
You need some force on the other side of the tube pushing the mercury down, which wasn't pushing the mercury up when the tube was right side up.
If that atmospheric pressure changes slightly be expansion or contraction of matter/molecules
Deal with the inital inversion before moving on.
Make sure people understand what happens there first.
which also allows the expansion of the small amount of atmosphere trapped inside the tube which is still under compression
Again, no it isn't.
The void was tiny, so small you couldn't even see it. The tube was then inverted and it became quite large. That means it is under reduced pressure, not compression.
Am I being fair here?
Only if you actually respond to arguments raised.
As you have ignored numerous objections already raised when you made this post and instead just repeated the same refuted BS; I would say no, you are not being fair.
For every action there is and equal and opposite reaction. It works for my theory as well you know.
Which has nothing to do with what we are discussing at the moment.
We are discussing why the person/car/object keeps moving.
You want to call it inertia without any real reason for it.
Because that is the word that was chosen to describe it. It is effectively the mass of the object, its tendency to stay in motion or at rest unless acted upon by an external force.
You want to say it isn't real, then tell us why things don't just stop and instead keep moving, at least for a bit.
The skateboarder accelerates down the ramp and then hits a spot where acceleration ceases and then becomes deceleration to match the effort of the mass displacing the atmosphere downwards.
This is not what I'm talking about.
I repeat, this is not what I'm talking about.
Good, it isn't what we were either.
We were talking about the skateboarder/car/whatever going up the ramp. They are going up, without applying any force to do so, yet keep going up.
WHY?
Why don't they stop instantly?
How come you can't grasp that I'm talking about holding a constant velocity under POWER/ENERGY.
Because you are yet to explain why that is important.
How are we meant to grasp something when you just continually assert it without any explanation or justification?
Decrease pressure is exactly that and decreasing pressure will still leave pressure which is absolute key to everything working as it does in any way shape of form.
A significant enough decrease in pressure is far closer to a vacuum than a simple "decrease".
The pressure at this level is insignificant and is incapable of explaining so many things.
so let's leave it out.
Then why is it pushing into the air?
Of course it matters, that's what makes barometers work.
Stop assuming barometers work under your theory.
I have explained why it works.
It works because of the density of the mercury and the force of gravity associated with it.
You are yet to explain it in your model.
It's the mercury in the dish and the lower atmospheric pressure the mercury in the dish is pushing against which allows the lower pressure atmosphere inside the tube to expand more back against the mercury up that tube.
The pressure inside the tube (in the void) is nothing compared to the atmosphere outside.
If it was as simple as that the mercury would go right to the top.