There are what are called 1st and 2nd order effects. Gravity is first order. The sloshing is second order. So as you say, scaling the model up does make additional factors matter relative to your 1 liter of gas on the table. But it's only the first order effects which make an appreciable difference when looking at it on a planetary scale.
Then if you say want to extend the model to your meteorogical model, you have to say, well... the density of air is different over the ocean because of evaporation. The gulf stream moves clouds consistently this way etc. But those things only matter after you've introduced gravity, and understood the earth's atmosphere as the "gravitational balloon" model. Then you introduce your sloshing to understand the next stage.
This way of thinking about things in terms of leading or second leading order effects when considering systems at varied scales is pretty common in physics.
Btw from lived experience I can tell you the only gulf between you and a 150 level physics class is that you are actually trying to learn it.
I think I'm following, but for clarification, when you say "unconfined" you mean bound within a vessel, but the vessel is able to expand? As in your example with heating the planet and the volume getting a little bigger? Or a like balloon?
Likewise with "confined" you mean like a steel can. Completely rigid?
If that's the case, this is my take. It's like having a spherical balloon with a spherical concentric interior hamster ball (stick with me). The balloon can expand and contract with an change in temperature or a change in number of molecules. It contains the entire volume. The hamster ball on the other hand only contains its own fixed volume. Molecules can flow into or out of the vents. The total weight contained within the ball can increase or decrease, but the volume will not.
The force that determines the expansion rate of the balloon and the mass contained within the ball is gravity. Density is diffusive. It decreases with increase in altitude. Increase the temperature and the gas molecules will run faster and faster. Being able to push the balloon out futher. Or, add more gas it will "stack higher".
If you had a purely confined system (i.e. the hamster ball has no holes). You have a pressure cooker. As you increase the temperature of the gas, the molecules move faster and faster, slamming into the walls of the ball. Eventually it will rupture.
All that said, you're correct. So far as I know as I know, earth shattering though it may be, there is no "glass ceiling" which will shatter from climate change (I definitely did that one on purpose and I'm not sorry). The model of the earth's atmosphere is as you say "unconfined" (caveate it is actually confined by gravity)
Final point. You could continue to add gas "indefinitely". That is, until the density at the surface of the earth is large enough to create a black hole. For that, you'd have to consult Stephen Hawking or read one of his paper on Black Hole Thermodynamics. Spoiler: Things can escape the grip of a black hole!
Once you download wikipedia, you can edit it and distribute. Other people with their own copies can merge your changes into theirs, or you can push your changes upstream. Even if they need to be signed to accepted. Doesn't that make Wikipedia more like the Linux Kernel and less like The Encyclopedia Britannica? Sure, for the kernel there is a "main and central" repo, but the whole point of git is that it isn't centralized. It's distributed.
In fact, in a loose way, wikipedia meets the criteria of Free Software. You can:
Read the source code
Modify the source code
Distribute the source code
Distribute your modifications to the source code
edit: wikipedia is predominately licensed under Creative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA) and the GNU Free Documentation License (GFDL)
Agreeish? (M)any one of us can download wikipedia. Does that still make it centralized when it is designed to be distributed that easily? That design choice is baked into the ethos. Centralized vs. Decentralized seems not to be binary.
When I got my last rejection letter, he told me he would help me find a job. I haven't heard anything since I followed up over a month ago.
I was also told things about the other candidates and was led to believe my chances were better than they apparently were. Unprofessional at best. Fucking sadistic at worst.
Check out Vacuum Wars on youtube. This is the steam mop I use https://www.amazon.com/Bissell-Sanitization-Flip-Down-Scrubber-1940A/dp/B0091YYUAM