# The Naked Scientists Forum

### Author Topic: Inside or outside ?..does it make a difference ? (a balloon lifting question)  (Read 4412 times)

#### neilep

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« on: 19/02/2008 23:10:23 »
Dearest Brethren and Sisteren !

Balloons are great !!...they are my all time favourite air or gas filled rubber things that come in packs ..(some come in packs of three..!!!...weird eh ? )

See them here all being balloony and bringing joy !

Say I had enough of them to attach to my car to make it float.....would they also make it float.....(by the use of magic-ala-tardis style).......if I could cram them all inside the car ?

Inflate my education and tell me.....cos I really car about ewe all !! *groan*

#### DoctorBeaver

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #1 on: 19/02/2008 23:20:23 »
The amount of lift would remain constant whether they were inside or outside. Consider - if the total volume of gas used in the balloons were pumped into your car, then so long as the car is airtight and the gas isn't compressed, it will still rise.

When you would have a problem, though, is as the car rises. If the balloons were outside then as they rise higher and the air becomes thinner, the external pressure will decrease and the balloons will expand. Although the balloons will still weigh the same, their volume will be greater so they will still displace the same amount of external air and you will still get lift. If, however, the balloons were inside they could only expand to fill the available space. There would therefore come a point where they could no longer expand and you would get no more lift.

#### another_someone

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #2 on: 19/02/2008 23:35:19 »
All I can say is that it would have to be a pretty large car to contain enough gas to offset the weight of metal in the car (and if the car was larger, so the amount of metal would increase, so having to make the car larger yet).

#### DoctorBeaver

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #3 on: 20/02/2008 00:01:17 »
Merc SLR. Carbon fibre bodywork, lots of magnesium instead of steel, etc.

#### lyner

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #4 on: 20/02/2008 09:48:40 »
Plus you would have to leave the engine, suspension and transmission behind; they would be too heavy!
Bearing in mind that balloons tend to have thin plastic envelopes, you would need to make quite a few compromises.
This was someone's attempt.

#### DoctorBeaver

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #5 on: 20/02/2008 09:51:42 »

#### Soul Surfer

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #6 on: 20/02/2008 10:01:41 »
Many years ago I saw an article about a man who tried to get airborne by using hundreds of children's balloons. It did nearly work but failed. It was proved that at that time it would always have failed. The reason was that the lengths of string needed to tie the balloons into a group added so much weight that beyond a certain point adding more ballons did not create any more lift because the strings were a heavy as the lift offered by the balloon.
« Last Edit: 20/02/2008 10:04:02 by Soul Surfer »

#### neilep

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #7 on: 20/02/2008 21:15:05 »
THANK YOU THANK YOU ALL for your wonderful responses.

#### turnipsock

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #8 on: 20/02/2008 22:50:15 »
http://en.wikipedia.org/wiki/Larry_Walters

I always thought this was urban myth but it appears to be true as it is on wiki.

« Last Edit: 20/02/2008 22:53:39 by turnipsock »

#### another_someone

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #9 on: 21/02/2008 00:45:59 »
http://en.wikipedia.org/wiki/Larry_Walters

I always thought this was urban myth but it appears to be true as it is on wiki.

But they were weather balloons, so larger, and fewer, balloons required, so fewer cables required (and it did not lift an entire car).

Ofcourse, the key point is, it was illegal (they don't like you having fun).

#### lyner

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##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #10 on: 21/02/2008 17:41:06 »
That looks really really brown trouser stuff.
I  hope he was wearing a parachute.
'Legality' is a local affair; there must be places in the World that it would not raise an eyebrow. But, yes, 'they' do tend to be spoilsports.
Lifestyles need to have  type approval these days.

#### The Naked Scientists Forum

##### Inside or outside ?..does it make a difference ? (a balloon lifting question)
« Reply #10 on: 21/02/2008 17:41:06 »