h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: the wonders of Helium balloons - A817445
Author: ~*SQUIGGLES*~ - U202036

I'd say that inhaling helium tops my list of: 'pointless yet amusing things to do when otherwise very unamused'

Hello Squiggles, welcome to Peer Review

I can remember wanting to do this for the first time - I got my chance when I had a weekend job in a department store one Christmas. We had a helium canister outside Santa's grotto to fill balloons for the kids coming out, but half of the helium went into our lungs, not the balloons We spent the entire day going up to customers and saying in a Mickey Mouse voice 'Can I help you madam?'

Anyways. As it stands now, your entry doesn't follow the Writing-Guidelines for various reasons, the most important being that it's mostly written in first person (I, me, we, etc). If you wanted to do some more research on exactly why helium affects the voice in the way it does and rewrite your entry, there'd be a spot for it in The Edited Guide as long as there's not already an edited entry on this subject. To find out if there is one, click on the link above for 'Advanced Search', then choose the field 'Search the Guide', enter the word 'helium', uncheck the boxes marked 'Recommended Guide Entries' and 'Guide Entries', and hit 'Search the Guide'.

The Peer Review forum is meant only for entries which are being submitted for inclusion in the edited section of h2g2 - anything else you write just becomes another part of your own personal bit of h2g2. If you want to leave this entry as it is, you can simply go to PeerReview, find your entry, and click on the 'Remove' link to take it out of Peer Review, but I think we'd all prefer it if you wrote something more

well then! I'm newly updated and out of first person!

Looking much better now

Anyone with a more scientific background than mine care to comment?

A very good article. And all correct as far as I can tell. Except for one thing. A helium ballon floating outside will continue to rise until the air pressure outside is the same as inside, then it will hover. (In fact no ballon is perfect so it will burst or all the helium will escape before that happens)

I think the title could be better, what do you think of "Helium Balloons and Helium Voices", not very good, but you get the idea.

Apart from that, it is very good. Well done!

'Fun with helium balloons'?

But it's not all about balloons is it, as someone commented you can get helium direct from a canister. How about "Fun with Helium"?

Even better

"A helium ballon floating outside will continue to rise until the air pressure outside is the same as inside, then it will hover."

Not quite right. The pressure inside a helium filled ballon is the same as the air pressure outside. If it were less, the balloon would callapse until it was the same. If it where greater inside, tha ballon would axpand. If to much expansion takes place, the ballon burts. The reason a helium ballon rises is that the density of helium is less than that of air for the same volume.

Any gas filled ballon will only hover if there is some way of altering its mass. As that is not possible with helium filled ballon of the type we are talking about, it will just keep rising until it busts.

A conventional balloon can be made to hover by either reducing the volume of gas, which will stop it rising, or throwing sandbags overboard, which will increase the rate of ascent.
Regards

Stuart

Ok, pressure was the wrong word, i should have said density. The density of air decreases with altitude, at a certain point the density would be the same inside and outside the balloon, and it would hover.

Still not quite right.

The density of air decreases with altitiue, so does the pressure. Consequently the balloon expands so the helium inside is at the same pressure as the air outsdide, retaining the same relative density between air and helium. Helium can never be the same density as air at the same pressure. As the pressure inside and outside the balloon will always be the same, the baloon will eventually expand beyond its limits and burst.

Take a look at weather ballons. When they are launched on the ground they appear to only have a small amount of helium inside with the evelope looking pear shaped. If the evelope was fully inflated on the ground, the balloon would burst long before it go to its required altitude of 70,000 feet plus. But one thing they don't do is hover. To do that there has to be some way of reducing the amount of helium in the balloon at the required height and I dont believe weather balloons have that capability. If you only put sufficient helium in the balloon at ground level to make it neutral at 70,000 feet, it would never get of the ground.

Regards

Stuart

I know my title is a bit... *ehem* off. I've been trying to think of a better one for a while now.

*will read the entry soon - but had to say this*

There is that wonderful, and possibly apocryphal story about how 'enfant terrible' Chris Morris, in his local radio days, filled a studio with helium gas before the morning show was to commence, and left the presenters sounding more Mickey Mouse than Mark and Lard...

Ok, what about a rigid structure like a metal box, what would happen then? I must admit I forgot to take into account the balloon expanding.

A rigid structure would work, but there is no substance yet known both strong enough and light enough to do the job. Put all the helium you like into a sphere made of some lightwight carbon fibre plastic, and it is not going to budge an inch, and even if it were possible, it would have to be pretty strong to withstand the pressure differential as it rose in the atmosphere, like the fusalage of an aircraft does.

It works with a rigid structure under water becasue water is far more denser than air.

Regards

Stuart

Hi Squiggles,

Sorry about going a bit off-topic in your PR thread, but it was begging for an explanantion.

Regards

Stuart

Ok, thanks for the explanation.

Witty Ditty, how did he get enough Helium to fill an entire room? It must have been a large proportion to effect their voices.

Ok, Stuart, explain why divers breath helium-oxygen mix?

Well....

> Radio studios are small, confined areas, so I don't think he needed much
> The story is apocryphal, as is much of Chris Morris' early japes.

Not sure if that answers your question Tango...

Stay ,
WD

"Ok, Stuart, explain why divers breath helium-oxygen mix?"

To prevent Nitrogen Narcosis. See A810244 About half way down under Symptoms

Regards

Stuart

That was a good question to ask you, wasn't it? Do I take it you are in the Royal Navy, or do you just happen to have Navy manuals? Your article on the bends has a few grammer errors, do you want me to list them, or haven't you got to that stage yet?

Yet another question (sorry for the of topic posts), can u recommend a way to start diving? Courses, places to take courses, that sort of thing. And also could you give an idea of price if you know it off the top of your head. Thanks!