MadSci Network: Physics |
There is NO reason to use hydrogen in preference to helium for lifting power; the buoyancy of hydrogen in air is 0.93 (where 1.0 is a rigid container containing a perfect vacuum) while that of helium is 0.85. The inflammability of hydrogen completely negates any minor lifting advantage you might get from it. There are good reasons that nobody uses hydrogen to lift their balloons. Helium (about 1/7 as dense as air) gives plenty of lift without the fire hazard. In fact, the only reason the Germans used hydrogen in their dirigibles is because they were often metal-skinned (and therefore puncture-resistant) and because the United States -- the chief source of helium in those days -- wouldn't sell them any. Dan Berger chemist and MadSci Administrator
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