Why do hot air balloons rise, while balloons filled with unheated air do not, even if they are made of the same material?

6 views 1 helpful Updated Jul 27, 2026
Appears in Class 8th
Solution ✔ Verified
  • AHot air is less dense than the surrounding cooler air.
  • BHot air is heavier than cooler air.
  • CHot air expands, creating a vacuum inside the balloon.
  • DHot air generates its own lifting force.
Explanation

When air is heated, its molecules move faster and spread out, making the hot air less dense than the cooler air outside the balloon. According to Archimedes' principle, the balloon experiences an upward buoyant force greater than its weight, causing it to rise.

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