[green iguana]

Helium has to lift way more than one gram per cubic meter.

[wbill]

1 kg per m^3.

I just looked it up.

Wish that I hadn't.

[Ramius]

Helium has to lift way more than one gram per cubic meter.

I think it's actually 1.1g per cubic meter, so my math up above was probably off by about 10%. But the difference in what it takes to lift even 30 lbs is orders of magnitude more than the volume of that balloon... it's not even close.

[Royal Wulff]

It’s more like 1kg (2.2 lbs) per cubic meter.

http://en.wikipedia.org/wiki/Lighter_than_air

[Voter62vb]

5 posts - 4 authors
I have looked up helium’s lift capacity and found that it is 1 m3 can lift 91.82566798 grams, or 0.2024409 pounds. This seems logical, but that’s not the ...
www.physicsforums.com/archive/index.php/t-19038.html - Cached - Similar

Just throwing this out.

[-YYZ-]

“Helium has to lift way more than one gram per cubic meter.”

A cubic meter of air weighs about 1.2 kg. A cubic meter of helium (at standard pressure and temperature) weighs about .18 kg. So, allowing for the weight of the enclosure, a cubic meter of helium might lift about 1 kg. So a 20 kg child would need about 20 cubic meters of helium to lift him or her, in addition to amount needed to lift whatever the balloon and other things weigh.

The real question is, how much excess lifting capacity did this contraption have, after accounting for the weight of the ballon and the stuff hanging off it?

[NELSON111]

According to How Stuff Works (http://science.howstuffworks.com/helium2.htm), A 6 ft diameter balloon with a capacity of 113 cu ft can lift 7 lbs. Move that up to a 12' di - It can lift 57 lbs. 24' can lift 455 lbs.

Seems to me that it could lift a 6 yr old...since my stick of a 7 1/2 yr old weighs 55 lbs.

And yes...Shep is an idiot. Kept calling it a hot air balloon...(and Hannity said it was powered)...blah blah blah. Idiots...