# Dense Helium Balloons: Will They Rise or Fall?

• Mentallic
In summary, a helium balloon would rise if helium was less dense than air, but would fall if helium became more dense than air. There are examples of this in real life, such as swim bladders used by fish and submarines.
Mentallic
Homework Helper
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?

Mentallic said:
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.

ryan_m_b said:
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?

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).

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DaleSwanson said:
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).

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

Oh thanks a lot you guys! This was really helpful

Last edited by a moderator:

## 1. Will a dense helium balloon still rise?

Yes, a dense helium balloon will still rise. Despite its increased mass, the buoyant force of the helium gas inside the balloon will still be greater than the force of gravity, causing it to rise.

## 2. How is a dense helium balloon different from a regular helium balloon?

A dense helium balloon contains a higher concentration of helium gas, making it more compact and increasing its overall mass. This can be achieved by either using a higher pressure helium tank or adding a heavier gas such as sulfur hexafluoride.

## 3. Will a dense helium balloon fall faster than a regular helium balloon?

Yes, a dense helium balloon will fall faster than a regular helium balloon. This is because the increased mass of the dense helium balloon will cause it to experience a greater force of air resistance, slowing down its descent.

## 4. Can a dense helium balloon be used for scientific experiments?

Yes, dense helium balloons can be used for scientific experiments. The increased density of the helium gas allows for greater control and stability in experiments, as well as the ability to lift heavier payloads.

## 5. How do dense helium balloons affect the environment?

Dense helium balloons can have a negative impact on the environment if not properly disposed of. The release of sulfur hexafluoride, a heavier gas used to create dense helium, can contribute to the depletion of the ozone layer. It is important to properly dispose of dense helium balloons and their components to minimize their environmental impact.

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