Question

In the blimp example discussed in the text and in class, why does the blimp descend

when the ballonets are inflated with air?

Both the air and helium gas are at equal pressures.

The air is less dense than the helium.

The air is more dense than the helium.

Answer 1

The blimp descends when the ballonets are inflated with air because **the air is more dense than the helium**.

The way a blimp works is by changing its overall density to control ascending and descending. When the ballonets inside the blimp are filled with air, it displaces some of the lighter helium gas, making the overall density of the blimp greater than the surrounding air. This causes the blimp to descend.

Conversely, when air is released from the ballonets, the helium gas expands, reducing the overall density of the blimp and causing it to ascend. The pressure of the gases does not directly affect the blimp's ascent or descent; it's the change in overall density that does.