Eli5 Does pressurizing gas effect the buoyancy because it makes it denser?
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Yes.
The buoyant force is equal to the weight of the displaced fluid. A 1 cubic meter object submerged in air will experience an upward buoyant force equal to the weight of 1 cubic meter of air.
If you increase pressure of the air, you increase the density, increasing the weight of the displaced fluid, increasing the buiyant force.
Yes. The buoyancy of an object comes down to the difference between its density and the density of the surrounding medium. Whether you’re talking about compressing the medium or compressing gas within an object then the buoyancy of the object will change.
Yes, this becomes apparent with scuba tanks
An 80 cubic foot aluminum tank when full and submerged in salt water “weighs” 1.4 pounds and will sink. If you empty the pressurized gas from it now the tank has an actual empty mass of just 37.6 pounds and has 4.4 pounds of upwards buoyancy.
As you use up the pressurized air within the scuba tank, the mass of the tank decreases but the volume of water it displaces remains the same so it transitions from wanting to sink slowly to wanting to float upwards a bit quicker
Yes.
ELI10:
An object with a fixed mass will be more buoyant in a gaseous atmosphere at 2atm than at 1atm. A container in a given fluid will be less buoyant when the container is filled with 2atm of air than 1atm.
ELI5: A helium tank gets heavier, the more helium you put in it.
**Not always.**
Consider how hot air balloons work. The energetic hot air expands to equalize with the surrounding atmospheric pressure, since it is not contained. The hot air is now less dense than the surrounding air. This creates a buoyant force, which lifts the basket.
Now consider the following: If you could contain the air in an ultra-light sealed container and heat it up, will it float?
>!No. Since the air is in a fixed container, it is not allowed to expand. Thus the density remains the same, as the number of air molecules in the fixed-volume container is the same. Notice that in this case, the air IS pressurized. So if you pressurize the gas by heating it in a closed container, it does not change its density, so there is no buoyant force. However, if you pressurize the gas by adding more gas, this does make the gas denser, as the other answers have pointed out. So buoyancy only depends on density, which is a dependent on both the temperature AND pressure of the gas. For a more comprehensive answer, check out the ideal gas law.!<
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