How do balloons float?

Answer 1

Balloons that are filled with hot air, hydrogen, or helium will float, or rise upward, because the less-dense gases inside them are displaced by the heavier air around them. Balloons will only rise until the gas density inside them is equal to the density outside. In the case of helium balloons, this may be above the elastic limit of the balloon, and it will pop or leak.

Answer 2

Balloons float because the gas inside them is lighter than the air outside. This creates a buoyant force that pushes the balloon upwards. Helium is commonly used in balloons because it is less dense than air.