Vacuum Balloon

[Technician1002]

Have you priced the stuff? You can order samples here. They don't take charge cards. http://www.airglass.se/sale.html

[POLAND_SPUD]

Poland_Spud's right!

yeah, as always 8)

Heh I expected it to be expensive, but I guess you can produce it yourself.

At least now it's no longer a matter of 'Is it possible?' but 'How the hell am I supposed to produce/get enough of it?'

[Technician1002]

I noticed it is not a solid. Hmm, I wonder if you took some of it, put it in a vacuum, and then added helium, then painted the result to seal the outside. Could it be made lighter than air?

[Heimo]

I noticed it is not a solid. Hmm, I wonder if you took some of it, put it in a vacuum, and then added helium, then painted the result to seal the outside. Could it be made lighter than air?

apparently they are already doing it...
read the description of this video:http://www.youtube.com/watch?v=HoCAxS4vqwQ

[whoa044]

Gas has mass. The only thing keeping a balloon stretched out, is the air pressure inside the balloon pushing out. The more gas inside the balloon, will cause a higher volume, but it is not linear.

It might take 0.5 psig to slightly inflate the balloon, then another 1 or 2 to actually make it stretch. As the balloon inflates, more surface area is exposed, meaning not as much pressure is required to inflate it even further.

That's why fully inflated balloons seem to weigh less than half inflated ballons.

The vacuum balloon pretty much is a concept that means the balloon's volume is constant, but pressure varies. I do not think this will work, because the frame you need to support the vacuum inside will be too heavy.

You might compare this to a submarine underwater, and as a relation the hull is the balloon. As you take water out from the inside, and expell it out from the sub, it will get lighter, relative to its surroundings. If it was totally filled with air, you could relate it to a vacuum in a 14.7psia environment.

[Lentamentalisk]

Right, you don't think it will work because nobody has gotten it to work yet.
Your logic doesn't work though. Submarines work. A submarine can gain buoyancy in water, despite the metal shell having a higher density than the water that surrounds it.

In theory, with strong and light enough materials, a vacuum balloon could work, just as a submarine works. The only question is whether we have sufficient materials, and whether there are designs that are especially strong.

Aerogel for example, can be made as light as air when saturated with helium. Therefor, in theory, with a thick enough shell of aerogel, it should be possible to create a vacuum balloon using it.