how much lighter is a vacuum than hydrogen?

[匿名]

2020-11-10 8:06 am

empty spaces weigh less than spaces that are not empty, so a space full of helium still has weight, even though balloons float.... how much 'lighter' would the same volume of space be if it was a vacuum? lets get over how balloons and several other things work for a second, this is a theoretical example.... if a "fully inflated" balloon was filled a vacuum, how much lighter would it be than if it was filled with helium? helium can lift roughly 60 lbs per 1,000 cubic feet and hydrogen can lift about 68 lbs per 1,000 cubic feet. how much can a vacuum lift?

回答 (1)

Morningfox

2020-11-10 8:36 am

✔ 最佳答案

Hydrogen gas at STP has a density 0f 0.08988 g/L = 5.611 lbs / 1000 cubic feet. So 1000 cubic feet of vacuum could life 68 + 5.6 = 73.6 pounds.

Problem is, hydrogen gas pushes out on its container, so the balloon can be kept inflated against air pressure. Vacuum doesn't do that, so the container has a pressure of 2116 pounds per square foot (outside area). You need a very strong material to resist that pressure, which means a thick steel container, and that means a LOT of extra weight. It's not worth the cost and trouble to get an extra 8% lift.

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