Why balloons are filled with helium?

Answer 1

Filling a balloon with enough helium for flight takes a lot of helium, hot air balloons only use hot air because it only takes a couple of tanks of propane to heat the air, which is much more cost effective than filling the balloon with helium.

Airships use helium because they are used to stay in the air for extended periods of time, so it makes sense to pay for the helium to fill it once, rather than the propane to keep the air hot.

Answer 2

Hydrogen is explosive and helium is inert. If a hydrogen balloon explodes as the result of a spark you can start dangerous fires especially where there are more of them nearby.

Answer 3

Because there isn't a high enough concentration

Answer 4

Helium is lighter (less dense) than air so it allows the ballon to float.

Answer 5

Helium is lighter than air. so helium balloons will rise up in air. also helium is chemically inert and safer to use.

Answer 6

Because Helium makes the balloon float, if you use air then it will just fall to the ground.

Answer 7

It's lighter than air so the balloons float.