Why do balloons float in air
4 responses | 0 likes
Started by wglassfo - Jan. 9, 2019, 7:18 p.m.

I happened to read an article which explained the tremendous weight of a cloud in the sky. Instead of being all light and fluffy, it is not uncommon for a cloud to weigh 11 million ibs. I suppose some bigger, some smaller but the article did not tell me that part.

Wow I thought. The article went on to explain that somebody measured the size of a cloud [how I do not know] and then calculated the amount of water in that cloud. Again I do not know how. Then of course it was a simple math question. That I do know how to do.

Any how, it seems that the air under that cloud is even heavier than the weight of the cloud. So: It follows that you see clouds in the sky. Wow: I did not know that. I thought they were just up there.

I do know that fog is merely a cloud at land level, so it must be really heavy, but then I thought about turning on my wipers in a fog, so that made sense

So I impress my wife with all my new found trivia and she floored me with a question

So says my wife of 53 yrs. [We got married really young].

So why do balloons float upward when they are blown up by a person. Balloons eventually come down, but only after losing the air inside. Hot air from a persons body only lasts so long and I think balloons must stay up long enough for body air and hemisphere air to reach equilibrium So why does a balloon blown up in my back yard, by myself or anybody, for instance, float in hemisphere air. Apparently all air must not be equal. But why is that??

So I went to my friend goggle

Maybe somebody else is sharper than I am but all my friend goggle told me was about helium balloons, hot air balloons, why we can float in water, why rocks sink in water and styrofoam floats and on and on. Now I skimmed it really fast but I knew all that but  did not find an answer

Can somebody answer my question so I can impress my wife with some more trivia??

Why do balloons blown up by a human float upward for at least some distance in the air

By 7475 - Jan. 9, 2019, 7:41 p.m.
Like Reply


I dont think they do.

Without assistance like a breeze or the warmth from someones breath they would drift downward -Pretty sure.

Actually, the moisture from breath would cause the air inside the balloon to be heavier  most times then the atmosphere surrounding it-Pretty sure. This has been untested by me.

 Now ,you take that sme balloon to DC and let "Them" blow it up and that baby is going to float for sure.



By metmike - Jan. 9, 2019, 9:47 p.m.
Like Reply

John is correct, that a balloon filled with similar ambient, atmospheric air will go down eventually because the balloon+ the air inside will weigh more than just the air surrounding it. 

The video below is interesting but I think they are wrong at the end about the amount  of buoyancy that an air filled balloon would get from the minuscule air pressure difference from its height from top to bottom.

Balloon Buoyancy - What makes balloons float?


However, this tiny amount might delay the falling of a balloon to the ground/surface by a tiny amount........that you are talking about. 

If the air inside is warmer, then it would be less dense/lighter and more buoyant and be able to overcome more of the force of gravity.

It would be interesting to heat a balloon inside the house with a blow dryer to over 100 degrees F, then release it outside when its 0 deg F.

Would this be enough to cause it to go up for a short while? Not sure but the air inside the balloon would quickly cool down and the balloon would drop to the ground.


Air Pressure + Gravity = Buoyancy


Related to this, the air pressure in your tires is very dependent on the temperature.

A couple of Winters ago, I was in Detroit at my Dads and the temp outside dropped to -10. The tire air pressure sensor lit up on his dashboard because the colder air caused the air pressure in his tires to drop by several lbs/sq inch.

When it warmed up, the air pressure in his tires went back up. 

Same thing with a basketball and football. Can you say deflate gate?

Tom Brady might have had his footballs deflated but the excuse offered, that they were inflated inside at a warmer temp then taken outside where it was colder, could have explained most of the difference(decrease) in pressure inside the footballs.

Billy Nye the science lie..........errrr, I mean guy showed that he has no idea about the physical laws of the atmosphere when he was interviewed live on major television shortly after the scandal erupted and did not know that air pressure inside a football goes down when the temperature drops. 


The funniest thing about it, is that Nye presents himself as a climate change expert and he didn't even know about the ideal gas law that they teach us in meteorology 101.

I liked Nye when he did his kids science shows. He's a gifted communicator and actor and understands great deal about science. He's a big fraud though, when it comes to understanding climate science.

Bill Nye 'the Science Guy' gets political


By wglassfo - Jan. 9, 2019, 10 p.m.
Like Reply

I suppose I will have to buy some balloons and find out

By metmike - Jan. 9, 2019, 10:10 p.m.
Like Reply

Great idea Wayne!