In a helium balloon- one that floats and rises to the ceiling it is elemental helium that is used to inflate the balloon. If you just blow into a balloon to inflate it then it is air inside the balloon which is a mixture of gases, principally nitrogen and oxygen (both elements). There are also other gases that are chemical compounds such as carbon dioxide.
The air inside a hot air balloon is the same as normal air around the balloon and the air you're breathing, only heated by the flame inside the balloon, hence HOT AIR balloon.
Natural air is always a mixture, and more or less homogenous in its major constituents. However, if the balloon was inflated by mouth, it will have less oxygen and more carbon dioxide than the air outside the balloon, which is also a mixture.
D: The hot air inside the balloon becomes less dense than the air outside the balloon.
The density of the air inside a hot air balloon is greatest when the air inside is coolest. As the air inside the balloon is heated, it expands and becomes less dense compared to the surrounding air, causing the balloon to rise.
The volume of a hot air balloon increases as the air inside the balloon expands when it is heated. As the balloon ascends and the air temperature decreases, the volume of the air inside the balloon decreases as well. The pilot can control the altitude of the balloon by controlling the temperature of the air inside.
Heating the air inside the balloon makes it less dense than the surrounding air, causing the balloon to float upwards. As the air inside the balloon cools, it becomes denser and the balloon descends. The pilot can control the altitude by adjusting the temperature of the air inside the balloon.
The pressure inside a balloon is created by the air molecules contained within the balloon pushing against the walls of the balloon. As more air is blown into the balloon, the number of air molecules increases, leading to a higher pressure inside the balloon.
When air is blown into a balloon, it fills the space inside. The pressure of the air increases, causing the balloon to expand. If the balloon is sealed, the air inside remains trapped, making the balloon float or hover depending on the amount of air inside.
D: The hot air inside the balloon becomes less dense than the air outside the balloon.
As the balloon cools down, the air inside will also cool. This will cause the air pressure inside the balloon to decrease, potentially leading to the balloon descending back to the ground due to the decreased pressure.
If the volume of the air inside a balloon increases while the mass remains constant, the density of the air inside the balloon will decrease. This means that the air inside the balloon will become less dense.
Adding more air to the balloon. Heating the air inside the balloon. Decreasing the volume of the balloon by squeezing it.