Buoyancy in Air-Filled & Vacuum Bottles: What's the Difference?

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Buoyancy in air-filled and vacuum bottles is influenced by the density of air and the volume of the bottle, which determines the mass difference and thus the buoyancy support. The upthrust experienced by both types of bottles remains the same, as buoyancy force is solely dependent on the fluid displaced, not the contents of the bottle. The discussion raises a question about whether the buoyancy force refers to the bottle itself or an object inside it. In a vacuum, there is no fluid to displace, which raises questions about the concept of buoyancy in that context. Understanding these principles clarifies how buoyancy operates in different scenarios.
samir240
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Will there be any change in buoyancy in bottle full of air and vacuum bottle?
 
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Look up the density of air and, if you know the volume of the bottle, that will tell you the difference in mass - which will tell you the difference in ' buoyancy' (meaning how much the bottle can support). The upthrust will be the same in both cases, of course.
 
The buoyancy force depends only on the fluid that is displaced. It does not depend on what displaces it.

In your OP it is not clear if you are asking about the buoyancy force on something inside the bottle, or the buoyancy force on the whole bottle immersed in another fluid.
 
the bouyancy force on something inside the bottle
 
In a vacuum, what would cause buoyancy?
 
I am following someone on Youtube who has built a rocket shaped (4 proprllers) drone for the world speed record ... He was having problems with internal heat from electical control gear and battery inside the sealed rocket (about 1kw waste heat) Speed is 500km/hr , I suggested a 4mm hole in the tip of the nose and 8mm hole at rear which should alow sufficient air cooling .. I said this will increase thrust because the air exiting is hotter .. a bit similar to a ram jet ... was I correct...
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