Balloons and the cold

[fifty-six]

I am working on an experiment and was planning on launching some balloons. Right before me and my friend decided to spend a bit more money he decided that helium filled balloons would not really rise well in the cold.

I am in a coastal area of Alaska and our temps lately have been about mid 20's to low 30's. Some of my experiment is designed on the lifting capacity of a balloon. I never really took into account the cold.



Will a standard size balloon still rise in the cold air?
And if so to what degree will the lifting capacity be reduced?

[Q.E.D.]

The lifting capacity of a helium balloon is not affected by air temperature (assuming the gas inside is at the ambient air temperature--which it soon will for a small balloon). Both the air outside and the helium inside lose volume as the temperature drops by about the same rate, per the ideal gas law, thus the buoyancy of the balloon remains roughly constant

[Q.E.D.]

Addendum: you'll want to have the helium tank outside and let it cool to ambient in order to maximize your lifting power.

[fifty-six]

Originally Posted by Q.E.D.

Addendum: you'll want to have the helium tank outside and let it cool to ambient in order to maximize your lifting power.

Perfect!!!


Thanks

[K364]

To maximize the buoyancy of a helium balloon, have the outside air cold (becomes more dense as it cools) and the helium warm as possible (becomes less dense).

[Q.E.D.]

Originally Posted by K364

To maximize the buoyancy of a helium balloon, have the outside air cold (becomes more dense as it cools) and the helium warm as possible (becomes less dense).

That'll work for about five minutes, until the helium inside the balloon cools to ambient. At that point, you'll have less buoyancy because the volume will decrease.

[fifty-six]

I did not know it was an important factor but I do need longer flights and a small weighted object attached.

Looks like ambient is the right choice.