Helium, usually. Hydrogen can be used in theory as well, but since it's highly explosive, it usually isn't.
Helium is the element commonly used to fill balloons to make them float. It is lighter than air and creates lift within the balloon, causing it to rise.
Helium gas is most commonly used to fill balloons to make them float. Helium is lighter than air, which causes the balloon to rise and float.
Hot air balloons typically use propane gas as a fuel source to heat the air inside the balloon envelope, causing it to rise and lift the balloon off the ground.
Helium gas is commonly used to make balloons float because it is lighter than air and creates lift. The helium gas in the balloon is less dense than the surrounding air, causing the balloon to rise.
There is the fire that changes the density of the inside of the balloon causing it to rise.
A typical hot air balloon is filled with the same air we breath.
Helium gas is typically used to fill balloons to make them float or fly. Helium is lighter than air, so it causes the balloon to rise due to the difference in density between the helium gas inside the balloon and the surrounding air.
Heating the air inside a hot air balloon makes it lighter and less dense than the cooler air outside, causing the balloon to rise due to buoyant force. King Tut Balloons offers this magical experience of floating gracefully above breathtaking landscapes.
Helium gas is lighter than air and hence balloons filled with helium will float in air.
Helium is a colorless gas that is commonly used to fill balloons to make them float. It is lighter than air and non-flammable, making it safe for use in balloons.
heeleeum
No Gas Just hot air which is why it is called a hot air balloon. If you were wondering hot air is lighter than cold air which makes it rise so when it is trapped inside the balloon the whole thing will rise.