Because it heats the air and of course the hot air will rise above the cold air causing it to float!
Hot air rises and the fire in the hot air balloon wants to go up and float in the air and since it's can't escape the balloon the fire just brings the balloon with it to float in the air
Fill a balloon part way with helium, make an animal out of it and have it float.
The air from your lungs has the same density as the air in our atmosphere. As a result a balloon inflated by a human using their lungs is unable to float.
Heilum combined with the light material of the balloon make it as light as air making it float.
A hot air balloon is able to float because the hot air being released into the balloon is less dense than the colder air surrounding it. Basically, the burner under the hot air balloons fills the balloons with hot air, enabling the balloon to rise through the cooler air outside.
The flame heats the air contained in the balloon. This causes the air to expand, thus it becomes less dense than the air surrounding the balloon. Once the air in the balloon is sufficiently less dense than the surrounding air to overcome the weight of the balloons materials, it will lift into the air.
As to the reason a hot air balloon floats has already been explained, I will answer your question regarding the flame. The gas burner provides the flame which is placed just in the mouth of the ballon, when lit it provides more heat to the cooling air in the balloon causing the balloon to maintain altitude.
Well it has a gas fueled flame and the flames heat makes the balloon part fill up with hot air. Hot air rises so the hot air balloon will float into the sky like a helium balloon would.
Air, like any other substance has weight, that weight is directly related to its density. The warmer the air is the less dense it is therefore the lighter it is. A balloon full of lighter air will float upward just like a piece of wood in a swimming pool, the wood is less dense than the water.
The key word there is float. There is nothing in space for a hot air balloon to float on.
Hot air rises and the fire in the hot air balloon wants to go up and float in the air and since it's can't escape the balloon the fire just brings the balloon with it to float in the air
A Balloon needs hot air to rise, the flame, which is gas burning, heats up the air in the balloon. As Hot air rises above cooler air the balloon takes off.
Fill a balloon part way with helium, make an animal out of it and have it float.
The air from your lungs has the same density as the air in our atmosphere. As a result a balloon inflated by a human using their lungs is unable to float.
Because air is not as dense as helium filed gallons so they won't float
If a balloon is inflated and tied closed, then held over a flame, it will surely pop. The heat of the flame will melt the rubber that makes the balloon.
Heilum combined with the light material of the balloon make it as light as air making it float.