3 ms·
Maybe I'm not understanding your proposal with the cylinder, but IIRC, it takes about a cubic foot of helium at standard temperature and pressure to lift an oun
by 13of40 10y ago
Maybe I'm not understanding your proposal with the cylinder, but IIRC, it takes about a cubic foot of helium at standard temperature and pressure to lift an ounce. Let's call it 3.5 cubic meters per kilogram in Euros. That means your cylinder has an inner volume of 7 cubic meters, which is silly, so it sounds like you're talking about a normal sized cylinder with compressed helium in it, which is heavier than air and which you'll be able to weigh on a scale just like anything else. (More or less.)
- thaumasiotes 10y agoThose numbers were made up to illustrate a point. I have no idea how buoyant helium is at STP and didn't intend to conform to any realistic scenario. "7 cubic meters at STP" is a perfectly fine empirical answer, and I guess you can get the mass of 7 cubic meters of helium from the ideal gas law. The point is, it makes no sense to say "the weight of the helium must be equal to the weight of the helium+cylinder system minus the known weight of the cylinder, just as the weight of a chicken on a plate is equal to the weight of the chicken+plate system minus the weight of the plate". You've got to bring in some extra information.
- deleted 10y ago[deleted]