Just thinking
Philosopher
- Joined
- Jul 18, 2004
- Messages
- 5,169
Even if it could be made, and behaved just like a weather balloon filled with hydrogen -- its lifting power wouldn't be much greater than the hydrogen balloon; a few percent, that's all.
DrRyanScarsella
New Blood
- Joined
- Jan 2, 2006
- Messages
- 12
anyone heard about the foam
I remember a couple of years back about a foam that had been invented that would expand upon compression. Something about a collapsed structured that expanded when the material was compressed. This wouldnt be the proper material, but a similar structure in a harder, lighter compound might be a place to start. It wouldnt be anymore efficient then a gas balloon, but it might make a neat science experiment. It might yield some new technology of materials to toy with but would cost a fortune to develope. It would be neat if you could make it the size small enough to float around indoors. I think i read about the foam in pop sci. It expanded in width when pulled axially, and when compressed axially, it got more narrow. I think they described it as a cube with the sides concaved in a four sided manner, like the top of an inverted tetrahedron, like a five sided pyramid with the base being one side of the cube. Im no physicist, but I thinks its a cool idea.
I remember a couple of years back about a foam that had been invented that would expand upon compression. Something about a collapsed structured that expanded when the material was compressed. This wouldnt be the proper material, but a similar structure in a harder, lighter compound might be a place to start. It wouldnt be anymore efficient then a gas balloon, but it might make a neat science experiment. It might yield some new technology of materials to toy with but would cost a fortune to develope. It would be neat if you could make it the size small enough to float around indoors. I think i read about the foam in pop sci. It expanded in width when pulled axially, and when compressed axially, it got more narrow. I think they described it as a cube with the sides concaved in a four sided manner, like the top of an inverted tetrahedron, like a five sided pyramid with the base being one side of the cube. Im no physicist, but I thinks its a cool idea.
Ziggurat
Penultimate Amazing
- Joined
- Jun 19, 2003
- Messages
- 61,715
That's a possibility, although the problem there becomes harder since at the same pressure, hydrogen gas is lighter than air by about a factor of 14, meaning that the weight of your vacuum balloon must be about 14 times smaller too, and I don't know if even a diamond sphere could pull it off under such conditions.
But there's still the problem of why use an expensive balloon when you could just use a glider? If the planet is near a sun, then getting a glider which could run perpetually on solar power might be a lot easier to do than a vacuum balloon.
billydkid said:
That might be easier to manufacture than our spherical shell example, and has the advantage that you could make essentially arbitrary shapes, but I suspect it wouldn't give you any advantage in terms of strength/weight ratio limits. So I don't think any metal or silicon foams would cut it, but maybe some hypothetical carbon nanotube foam might be strong enough.
Presumably, the air pressure in the room would go down proportionally to the degree to which the balloon "filled" the room.
Ziggurat
Penultimate Amazing
- Joined
- Jun 19, 2003
- Messages
- 61,715
Basically a small explosion: the air surrounding your void would come rushing in, and when the air coming in from all directions collides in the middle, it will have to stop very quickly, which means that it will reach very high pressures at the center, and so you'd have a VERY loud bang. Might spray out bits of your shattered balloon, too.
Just thinking
Philosopher
- Joined
- Jul 18, 2004
- Messages
- 5,169
Sort of like breaking a TV vacuum tube -- do not try this!