Very interesting, but I don’t see how replacing the same volume of air in our lungs with helium doesn’t make you lighter. It’s the same volume, so the volume displacement zeroes out in any equation - I think that poster may mean as compared to empty lungs. Even then I think they’re mistaken - otherwise a blimp/balloon wouldn’t work, as it too is displacing air around itself, and increasing in volume.
Very interesting, but I don’t see how replacing the same volume of air in our lungs with helium doesn’t make you lighter. It’s the same volume, so the volume displacement zeroes out in any equation - I think that poster may mean as compared to empty lungs. Even then I think they’re mistaken - otherwise a blimp/balloon wouldn’t work, as it too is displacing air around itself, and increasing in volume.