Gas balloon
balloon filled with gas less dense than air
A gas balloon is a kind of balloon that uses a gas of low density to fly using buoyancy. Gas balloons sometimes fly very high, very far, and for a very long time.
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A gas balloon is different from a hot air balloon. A hot air balloon uses a fire to lower the density of air. A gas balloon does not use fire.
The most common use for gas balloons are to measure the atmosphere. These are called weather balloons.
Some gas balloons carry people.
