Subject:
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Re: LEGO RCX Skydivers
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 9 Nov 1999 22:15:19 GMT
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Original-From:
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Pete Hardie <pete.hardie@dvsg.[avoidspam]sciatl.com>
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Viewed:
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935 times
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Robert Munafo wrote:
>
> Either my calculations are wrong, or you have a different concept of what is a
> "staggering" amount of helium. Here are my calculations:
>
> Each gram-mole of gas at STP [1] takes up 22.41 liters (cubic decimeters) of
> space.
>
> The weight of a mole of air is about 28 grams (a little more actually, but I'm
> being generous), and the weight of a mole of helium is 4 grams; thus the net
> bouyancy per mole of helium is 24 grams [2]
>
> Net bouancy per liter of helium = 24 / 22.41 = 1.07
>
> Volume of a sphere 1 meter in diameter is 4/3 pi r^3, where r is 5 decimeters,
> which comes out to about 523.6 liters.
>
> So a spherical balloon of 1-meter diameter and filled with helium would have
> about 560 grams of bouyancy, or about 19 ounces for you non-Metric dudes.
>
> For comparison, the "fish" blimp that swam around in the Media Lab during its
> first year or two was about 2-3 times this volume (same diameter but about 3
> times the length)
>
> What am I missing?
Mostly my hyperbole....
Still, getting envelopes for that amount of helium is difficult.
--
Pete Hardie | Goalie, DVSG Dart Team
Scientific Atlanta |
Digital Video Services Group |
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Message has 1 Reply:
 | | Re: LEGO RCX Skydivers
|
| (...) What about from Edmund Scientific? --- Chris Osborn FozzTexx Enterprises 707 226 7629 - Voice 2136 Coronado Ave. 707 581 1797 - Fax Napa, CA 94559 <fozztexx@fozztexx.com> (URL) (25 years ago, 9-Nov-99, to lugnet.robotics)
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Message is in Reply To:
| | Re: LEGO RCX Skydivers
|
| Either my calculations are wrong, or you have a different concept of what is a "staggering" amount of helium. Here are my calculations: Each gram-mole of gas at STP [1] takes up 22.41 liters (cubic decimeters) of space. The weight of a mole of air (...) (25 years ago, 9-Nov-99, to lugnet.robotics)
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