Question

Why is a balloon filled with hot air moves upwards?

Answer 1

The molecules in the air start to migrate and spread out as the air within the balloon warms up, making the air less dense. The heated air rises over the surrounding, cooler air. The heated air is pushed upward as a result, lifting the balloon along with it.

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Answer 2

Answer: When the air inside the balloon is heated, the molecules in the air begin to move around and spread out, and the air becomes less dense. The surrounding, colder air falls beneath the hot air. This forces the warm air upward, which pushes the balloon up with it.