A question of lifting bodies underwater

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SUMMARY

The discussion centers on the buoyancy of two rubber-coated Kevlar balls, one filled with air and the other with helium, when submerged underwater. The helium-filled ball exhibits slightly higher buoyancy due to its lower weight compared to the air-filled ball, resulting in a net force that is marginally greater to keep it submerged. The difference in lifting forces is quantified at approximately 0.1%. Accurate measurement of these forces requires precise instruments.

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  • Understanding of buoyancy principles
  • Knowledge of gas properties, specifically helium and air
  • Familiarity with rubber-coated Kevlar materials
  • Experience with precision measurement tools
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  • Study the physical properties of helium compared to air
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Dr Quest
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If I have two rubber coated kevlar balls, one is filled with air and the other has a gas like helium in it, if submerged underwater, would the ball with helium be harder to keep underwater than the air filled ball would be, or would they be equal in their buoyancy?
Also is helium easier to compress than air, I would imagine it would be but I don't have any schooling in this field.
Thanks for the site, and any answers to my questions.
 
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The way the definition of buoyancy works, the buoyancy is the same - what is different is the weight of the two gas-filled spheres. Since the one filled with helium is lighter, the net force required to keep it submerged is higher.
 
Russ_watters is right. But you cannot feel the difference. You must measure the two lifting forces with a very precise device. The difference in lift is about 0.1%.
 
Thanks for the info!
 

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