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You Are Gay 7 Feb 2008 17:17

Physics (?) Question
 
How would you go about calculating how much helium would be required to lift a certain weight and by extension what volume of space is required to enclose the helium?

I assume this amount of helium required would vary with altitude so let's set the altitude at 1000m. To help me work out other things could whoever is good enough to show me how to do this do it for an altitude of 2000m also. The weights should be 1k and 10kg.

Also what value of hyrdogen would i need to do this for hydrogen?

Thanks.

Knight Theamion 7 Feb 2008 21:00

Re: Physics (?) Question
 
What is the temperature? And does the temperature rise or fall if we go up? (although you want to lift a certain weight so I guess overcoming 'gravity' at a certain point would be enough)

Oh and what is the outside pressure or do we asume 'normal conditions' (whatever that may be)... you need to specify your 'expiriment' a bit.

Sun_Tzu 7 Feb 2008 23:11

Re: Physics (?) Question
 
Helium rises because it's lighter than air, in order to lift a given weight you need to provide enough helium for the relation to the same volume of air being the same as the weight of the object you are lifting or more. As the object rises, you have to provide again enough new lift to overcome the effect of gravity on the object as it rises. Temperature will effect the volume of the gases and the ratios of helium to air and thus the lift-capacity of a unit of helium.

Physics formulae I don't know, but atleast that's the principle of it.

Alessio 8 Feb 2008 00:15

Re: Physics (?) Question
 
Quote:

Originally Posted by Sun_Tzu
Helium rises because it's lighter than air, in order to lift a given weight you need to provide enough helium for the relation to the same volume of air being the same as the weight of the object you are lifting or more. As the object rises, you have to provide again enough new lift to overcome the effect of gravity on the object as it rises. Temperature will effect the volume of the gases and the ratios of helium to air and thus the lift-capacity of a unit of helium.

Physics formulae I don't know, but atleast that's the principle of it.

How come you're so smart? <3

_Kila_ 8 Feb 2008 00:16

Re: Physics (?) Question
 
how come you're a turk?

Alessio 8 Feb 2008 00:19

Re: Physics (?) Question
 
I'm not, you simpleton. Not even close.

furball 8 Feb 2008 00:34

Re: Physics (?) Question
 
Yeah you are. You even smell like a Turk.

Alessio 8 Feb 2008 01:17

Re: Physics (?) Question
 
I never smell Turks, so I wouldn't know.

But Furball, when you were sniffing a Turk, you might've smelled some familiar, yet unpleasant odors. But since we've never met you cannot know how I smell. So when you were sniffing a Turk you might've thought of me, but whatever the smell resembled, it certainly wasn't me. However, that Turk could've smelled like something that you do know. Your dad's penis for example. Or it could even have reminded you of some cool person that you've met in your life, in which case it is understandable that you made the connection with me.

QazokRouge5 8 Feb 2008 04:41

Re: Physics (?) Question
 
There's different grades of helium if memory serves...

You Are Gay 8 Feb 2008 12:44

Re: Physics (?) Question
 
OK thinking about it more i guess it's maybe the density of the gas that matters (hyrdogen, helium and air). The density alters with temperature and pressure so say the temperature stays constant you just need to know the pressure at 1000m and 2000m (which is and respectively).

The air density thing shows you how to calculate it at altitude but i'm not the best with calculations.

Anyways ... i still need help please.

All Systems Go 8 Feb 2008 13:26

Re: Physics (?) Question
 
I think this calls for an experiment using a plane an an infinite runway!

Mzyxptlk 8 Feb 2008 13:34

Re: Physics (?) Question
 
Maybe make it so the runway is like a threadmill.

All Systems Go 8 Feb 2008 13:35

Re: Physics (?) Question
 
Genius!

Radical Edward 15 Feb 2008 16:59

Re: Physics (?) Question
 
the density of helium is

0.1786 g/L

and air is

1.2 g/L

so the difference is about 1g/l.

work out the mass of the thing you want to lift in grams, and then you need about that many litres of (pure) helium - you also have to include the container of course in the mass calculations, since you need tp pick that up too..

I did this while drunk, picking up wine glasses with party balloons - though admittedly the helium was probably not very pure. it took a suprisingly large number, actually.

All Systems Go 15 Feb 2008 17:32

Re: Physics (?) Question
 
That's a cool party trick, but do you have to bring your own helium and balloons with you?

Yahwe 15 Feb 2008 23:55

Re: Physics (?) Question
 
Quote:

Originally Posted by Radical Edward
the density of helium is

0.1786 g/L

and air is

1.2 g/L

so the difference is about 1g/l.

work out the mass of the thing you want to lift in grams, and then you need about that many litres of (pure) helium - you also have to include the container of course in the mass calculations, since you need tp pick that up too..

I did this while drunk, picking up wine glasses with party balloons - though admittedly the helium was probably not very pure. it took a suprisingly large number, actually.

that's cheap glasses for you

Yahwe 15 Feb 2008 23:55

Re: Physics (?) Question
 
Quote:

Originally Posted by All Systems Go
That's a cool party trick, but do you have to bring your own helium and balloons with you?

as you can guess he gets invited to as many parties as you do

All Systems Go 16 Feb 2008 15:13

Re: Physics (?) Question
 
Whereever I go a party just develops.

Invitations are for losers.

Radical Edward 16 Feb 2008 19:14

Re: Physics (?) Question
 
Quote:

Originally Posted by Yahwe
that's cheap glasses for you

fortunately, since we smashed a few.

Radical Edward 16 Feb 2008 19:15

Re: Physics (?) Question
 
Quote:

Originally Posted by All Systems Go
That's a cool party trick, but do you have to bring your own helium and balloons with you?

no, but we had to take our own liquid nitrogen.

djbass 17 Feb 2008 01:41

Re: Physics (?) Question
 
Quote:

Originally Posted by Radical Edward
I did this while drunk, picking up wine glasses with party balloons - though admittedly the helium was probably not very pure. it took a suprisingly large number, actually.

Funny enough I did the same thing at my mates wedding only using cutlery instead. It didn't take an overwhelming quantity of balloons either. It was quite amusing as the odd knife or fork floated its way infront of the audience during the reception speach.

Yahwe 17 Feb 2008 01:43

Re: Physics (?) Question
 
Quote:

Originally Posted by djbass
Funny enough I did the same thing at my mates wedding only using cutlery instead. It didn't take an overwhelming quantity of balloons either. It was quite amusing as the odd knife or fork floated its way infront of the audience during the reception speach.

We can only imagine the arguements the engaged couple had over inviting you ...

All Systems Go 17 Feb 2008 14:09

Re: Physics (?) Question
 
Quote:

Originally Posted by Radical Edward
no, but we had to take our own liquid nitrogen.

and a bottle of wine?


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