# Balloons and the cold **URL:** \ **Category:** Factual Questions\ **Created:** [December 18, 2008, 2:04am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679 "2008-12-18T02:04:08Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [December 18, 2008, 2:04am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/1 "2008-12-18T02:04:08Z")
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? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 18, 2008, 2:16am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/2 "2008-12-18T02:16:07Z")
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 ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 18, 2008, 2:21am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/3 "2008-12-18T02:21:36Z")
Addendum: you’ll want to have the helium tank outside and let it cool to ambient in order to maximize your lifting power. ---
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [December 18, 2008, 2:25am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/4 "2008-12-18T02:25:21Z")
> [@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 ---
**Author:** ![K364](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k364/32/5_2.png) [@K364](https://boards.straightdope.com/u/K364)\ **Post date:** [December 18, 2008, 2:32am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/5 "2008-12-18T02:32:27Z")
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). ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [December 18, 2008, 2:36am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/6 "2008-12-18T02:36:18Z")
> [@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. ---
**Author:** ![fifty-six](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@fifty-six](https://boards.straightdope.com/u/fifty-six)\ **Post date:** [December 18, 2008, 2:41am UTC](https://boards.straightdope.com/t/balloons-and-the-cold/477679/7 "2008-12-18T02:41:23Z")
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.