Topic: Pressure in a balloon

Is the pressure inside a balloon greater than that outside?
One of my friends says....yes, it is. Other says....no, it is not.
I am totally confused... What is a reality?


Re: Pressure in a balloon

In principle, balloon cannot have its inside pressure greater than that outside.

Consider an ‘ideal’ balloon which responds proportionately and immediately to the changes in its air content. If you blow air into it, it inflates. That means if you try to increase the pressure inside, the balloon rejects the change in pressure though increase in volume. (Thanks to its elasticity…) In other words, it tries to maintain the inside pressure equal to that of outside. If you keep on blowing more and more air inside, its inflation continues. After each blowing, the inflation stops only when the pressures inside and outside is similar. For an ideal balloon, you can push in as much air as you can. But in the case of a real balloon, there is a limit for its stretchebility. When this is exceeded, balloon cannot continue to expand further for accomplishing the equalisation of the pressure and consequently it bursts. In short, balloon will never have air at higher pressure inside it.

Addendum: In the case of a real balloon, its skin will have a small rigidity (in spite of its elasticity). Hence, the balloon can tolerate an inside pressure which is slightly (…but only slightly) higher than that outside.


Re: Pressure in a balloon

Thanks. Now my doubt is clear. No more confusion now...
I will convey the facts to my friends.....