Why do hot air balloons float?
Show answer & explanation
Answer: Hot air is lighter than cold
Hot air is lighter than cold ✓ — Correct! Heating air makes molecules move faster and spread apart, reducing density. The hot air inside weighs less than the cold air outside, creating buoyancy. The balloon rises like a bubble in water!
The balloon pushes air down — Wrong. Balloons don't push air for thrust. They float because hot air is less dense than surrounding cold air.
Flame creates upward thrust — Wrong. The flame heats air, it doesn't create thrust. Buoyancy from density difference provides lift.
More Transportation questions
- Why is it misleading to say that single-track vehicles like motorcycles mainly lean and stay stable because their wheels act like gyroscopes?
- Why does the front wheel of a leaned motorcycle often seem to find a useful steering angle without the rider holding it rigidly?
- Why can a tilted motorcycle tire help push the bike sideways through a curve instead of just rolling straight ahead?
- Why does taking the same motorcycle curve faster require noticeably more lean?
- Why does the bike-rider system need a lean angle when a motorcycle follows a steady road-speed curve?
- What actually happens just after a rider pushes the left grip forward to begin leaning a motorcycle left?