Question on lifting power of gases

In summary, the lifting power of a balloon is determined by the volume of air it displaces, not its contents. However, the load it can carry is affected by the weight of the balloon and its contents. Removing helium from the balloon can increase its lifting capacity, but this is only a theoretical scenario as finding a lightweight, rigid balloon capable of containing a vacuum is difficult.
  • #1
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take a balloon filled with helium if you where to make the balloon rigid, without changing its weight, then suck half of the helium out of it. would the balloon, with the same volume but different density, have more lifting power?
 
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  • #2
What produces the "lifting power" is the buoyant force due to the air pressure acting on the balloon. That buoyant force depends on the volume of air displaced, not on what's inside the balloon. But the load that the balloon can lift is reduced by the weight of the balloon material plus whatever is inside the balloon. So by removing some helium, the balloon can lift an additional load equal to the weight of that removed helium. (Even better would be to remove all the helium! Realize that this is a thought experiment only--lightweight, rigid balloons that can withstand atmospheric pressure while containing a vacuum are hard to come by. :wink: )
 
  • #3


The lifting power of a gas is determined by its density, not just its volume. Therefore, if half of the helium is removed from the balloon, the remaining helium will have a higher density and therefore less lifting power compared to the fully inflated balloon. The rigid nature of the balloon will also affect its lifting power, as a rigid structure can withstand more weight than a non-rigid one. However, the overall lifting power of the balloon will ultimately depend on the weight of the balloon itself, as well as any additional weight that may be attached to it.
 

1. What is the lifting power of gases?

The lifting power of gases refers to the ability of a gas to exert an upward force on an object. This force is known as buoyancy and is dependent on the density of the gas compared to the density of the surrounding air.

2. What factors affect the lifting power of gases?

The lifting power of gases is affected by several factors, including the density and temperature of the gas, the volume of the gas, and the weight and shape of the object being lifted. Additionally, the atmospheric pressure and altitude also play a role in the lifting power of gases.

3. How does the lifting power of gases relate to hot air balloons?

Hot air balloons utilize the lifting power of gases, specifically heated air, to rise and stay afloat. As the air inside the balloon is heated, it becomes less dense and therefore more buoyant, causing the balloon to rise. The amount of heat and the volume of the balloon determine the lifting power and how high the balloon can go.

4. What is the difference between the lifting power of helium and hydrogen?

Helium and hydrogen are both commonly used gases in balloons due to their high lifting power. However, helium is lighter than hydrogen and therefore has a slightly higher lifting power. Hydrogen, on the other hand, is highly flammable and poses a safety risk, whereas helium is non-flammable.

5. How is the lifting power of gases used in airships and blimps?

Airships and blimps use the lifting power of gases, typically helium or hot air, to remain airborne. The gas is contained within an envelope or balloon-shaped structure, and the lifting power is controlled by the amount of gas and the weight of the structure. This technology is often used in transportation and advertising.

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