That's the oversimplification produced by round Earthers who need there to be "gravity" in order to justify their rotating orbiting tilting "planet". Earth is a world, not a planet.
No, that is an actual explanation of how things work, something people like you can't produce.
We need gravity to explain observations.
Your delusional nonsense where things magically go down just for being heavier than air works equally well for a FE or a RE.
This is because you have no justification for the directionality.
A magical downwards force with a universal down is no more justifiable than a magical downwards force towards Earth (or the nearest large mass).
If I were to toss a thin log and a brick, weighing roughly the same, into a body of water then I would see the force of buoyancy (if you can call it a force, you seem to have fast and loose definition of what is and isn't force, judging from past experience) in both. The brick however has more density in a smaller space and is less hydrodynamic. Sinks like, well, a brick. The log tends to float.
And the question is why?
Gravity explains it quite simply.
The downwards force on the brick due to gravity is greater than the upwards force due to buoyancy so it sinks.
For the log the opposite is true so it rises to the top of the water, where the buoyant force is then reduced (due to less water displaced) until it matches the downwards force due to gravity.
And the reason the force of gravity is down, is because it is a force of attraction to the large mass of Earth.
Nothing to do with gravity, absolutely everything to do with the wood being less dense per sq inch than the water
Why?
Why should being less dense make it float?
Why should being more dense make it sink?
If force were really what caused movement, then density should be a force.
No, as forces are what accelerates objects, and density is not a force, density cannot be what accelerates objects.
So you need something other than density.
The other big reason why density is not a force is that force needs a direction. Density does not have any direction.
But it isn't gravity that causes objects to sink. The brick and the log I've used are the same weight. Buoyancy is behind both reactions.
Gravity causes objects to sink, but that doesn't mean it is the only force. If you remove the water, removing the buoyant force, the object still sinks. But without the water (or some other fluid to take its place), the object wont float.
Place it in a fluid, and then you have buoyancy, with the buoyant force an upwards force.
The water causes it to float, gravity causes it to sink.
And the reason water causes it to float is because gravity causes the water to go down more.
It is like a see-saw.
If you place the volume of water the brick displaces on one side, and the brick on the other, gravity is pulling the brick down more, so it wins, so it goes down and the water goes up.
But if you do the same with the log, then the water wins, so it goes down and the log goes up.
We also see that the fluid causes an apparent reduction in weight based upon the volume displaced, with that reduction proportional to the density of the fluid.
Even without placing something in an environment without a fluid, we can extrapolate back to no fluid, and see there is still a downwards force, a force that is proportional to mass.
What would cause that in your fantasy?
And this also shows the downwards force due to gravity is proportional to mass, the upwards force due to buoyancy is proportional to the mass of the fluid displaced.
We also see this in other systems, showing what buoyancy is doing, such as if you tie a helium filled balloon to a van on the inside and accelerate. The helium balloon is pushed forwards by the formed pressure gradient in the air.
And that principle is used in centrifuges.
They explain gravity as being generated from rotation of the Earth.
That is a blatant lie that you have already had called out.
Objects would be attracted to Earth due to gravity regardless of it rotated or not.
What the rotation does is vary the apparent acceleration due to gravity, and as a consequence make Earth's surface oblate, bulging at the equator.
So it isn't gravity that is bogus, it is your blatant lie about it that is bogus.
This is why you can build extra large jets weighing hundreds of thousands of pounds. Weight is dispersed by alot of empty space and the object is aerodynamic. It does in the sky what a boat does in the sea.
No, it doesn't.
With a boat in the sea, if you stop it it stays afloat.
With a plane in the sky, if you stop it it falls out of the sky.
A plane flies due to lift, not buoyancy.
And you know what? This layer model matches what we know of the atmosphere
The issue is explaining it.
What is causing this layering? What is maintaining this pressure gradient?