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.
Helium by volume is lighter than air. That metric is called density.
So if you displace the volume in your lungs with helium that weighs less than the air that’s usually there, you will weigh less.
Physics!