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Speaker 1: Welcome to brain Stuff from how stuff works dot com

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Speaker 1: where smart Happens. Hi, I'm Marshall Brain with today's question,

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Speaker 1: what a balloon filled with vacuum instead of helium float?

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Speaker 1: At sea level? Air weighs about one point to five

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Speaker 1: grams per leader. A leader of helium, on the other hand,

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Speaker 1: weighs about point one eight grams. If you weigh a

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Speaker 1: one leader bottle filled with air and then weigh the

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Speaker 1: same bottle filled with helium, it will weigh about one

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Speaker 1: gram less. If the bottle itself weighed less than a gram,

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Speaker 1: you couldn't weigh it at all because it would float.

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Speaker 1: You would have to turn the scale upside down and

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Speaker 1: put it above the floating bottle to check its negative weight. Generally,

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Speaker 1: a balloon has to be several leaders in size before

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Speaker 1: that one gram per leader weight difference of helium versus

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Speaker 1: air is enough to overcome the weight of the balloon

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Speaker 1: itself and float. If you could somehow fill a one

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Speaker 1: leader bottle with a vacuum, it would float even better.

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Speaker 1: A perfect vacuum ways zero grams, so a leader of

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Speaker 1: perfect vacuum ways zero grams, and that's point one eight

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Speaker 1: grams less than a leader of helium. The problem, of course,

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Speaker 1: is that building a lightweight container that can hold a

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Speaker 1: vacuum is not nearly as easy as building a container

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Speaker 1: that can hold helium. The phrase nature of horrors of

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Speaker 1: vacuum sums it up nicely. If you could figure out

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Speaker 1: a way to do it, however, you could be set

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Speaker 1: your vacuum balloon would float even better than a helium balloon.

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Speaker 1: Not that you don't need to have a perfect vacuum

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Speaker 1: for this to work. Any air that you take out

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Speaker 1: of the container helps a vacuum balloon to float. Do

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Speaker 1: you have any ideas or suggestions for this podcast? If so,

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Speaker 1: please send me an email at podcast at how stuff

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Speaker 1: works dot com. For more on this and thousands of

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Speaker 1: other topics, go to how stuff works dot com.