Dense Helium Balloons: Will They Rise or Fall?

[Mentallic]

I just need some clarification on this.

It is well known that a balloon filled with helium will rise since helium is less dense than air, but what if the balloon were to stay the same weight, but the elastic itself has become much stronger, thus we could concentrate the helium even more, creating a dense helium balloon. Will it rise slower / fall to the ground?

And are there any examples of this in real life?

 

[Ryan_m_b]

I just need some clarification on this.

It is well known that a balloon filled with helium will rise since helium is less dense than air, but what if the balloon were to stay the same weight, but the elastic itself has become much stronger, thus we could concentrate the helium even more, creating a dense helium balloon. Will it rise slower / fall to the ground?

And are there any examples of this in real life?

If the density of the helium (g/cm3) ever exceeds the density of the air it will fall. Assuming for a second that the balloon has no weight itself and is 1 litre in volume then filling it with helium at the same pressure as the atmosphere will cause it to rise. If you keep increasing it eventually the pressure will drive the density of the helium to greater than that of the air, no longer being buoyant it will fall.

 

[Mentallic]

If the density of the helium (g/cm3) ever exceeds the density of the air it will fall. Assuming for a second that the balloon has no weight itself and is 1 litre in volume then filling it with helium at the same pressure as the atmosphere will cause it to rise. If you keep increasing it eventually the pressure will drive the density of the helium to greater than that of the air, no longer being buoyant it will fall.

Thanks, I was quite sure that was the case. Would you know of any real life example that I could use to intuitively back up these claims?

 

[DaleSwanson]

I guess it's not exactly the same thing, but the first thing that came to my mind were swim bladders used by fish (and I think submarines use a similar concept).
http://en.wikipedia.org/wiki/Swim_bladder"

 

[maimonides]

The Cartesian Diver is something like that.
http://en.wikipedia.org/wiki/Cartesian_diver

 

[Mentallic]

I guess it's not exactly the same thing, but the first thing that came to my mind were swim bladders used by fish (and I think submarines use a similar concept).
http://en.wikipedia.org/wiki/Swim_bladder"

The Cartesian Diver is something like that.
http://en.wikipedia.org/wiki/Cartesian_diver

Oh thanks a lot you guys! This was really helpful