No. Hot air is just that - regular air heated up. Hydrogen is one gas, one type of molecules only.
Jacques Alexandre Charles first attempted to use hydrogen as a replacement for hot air in hot air balloons in 1783. This led to the first manned flight using hydrogen gas in December of the same year.
A hot air balloon doesn't contain helium or hydrogen.
the hot air ballon is a thing
'Hot air' balloons don't use hydrogen. They use hot air. Balloons that use hydrogen are not referred to as 'hot air' balloons. The only balloons that can accurately be referred to as 'hot air' balloons are the members of the balloon population that derive their lift/buoyancy from the presence of hot air. Of course, if a balloon used no hot air, then it could freely be referred to as a 'hydrogen' balloon, a 'helium' balloon, a 'water' balloon, etc., depending in congruent harmony with the nature of whatever substance had been chosen with which to inflate it it in order to maintain its fulsome shape.
Hydrogen is the lightest gas found in air.
A sheep, chicken, and a duck all at the same time
Hot air balloons use hot air. They have a burner to heat the air. Hydrogen balloons were too dangerous because hydrogen is highly flammable, even static electricity could cause an explosion. Helium is safer because helium is not flammable.
Hydrogen is not used to inflate hot air balloons. Just regular air is used which is then heated to make the balloon more buoyant as hot air weighs less than cold air. Hence the name hot air balloons.
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hydrogen, helium, hot air
As it rises, outside air pressure decreases, and the hot air inside expands and fills the balloon. Same thing is true of large helium balloons.