Re: ballons burst at 35 km
Posted by Amaranth Rose on Jun 19, 2002 at 04:32
Re: ballons burst at 35 km (paul baughn)
As a weather balloon rises, the quantity (mass, number of moles) of helium remains constant, while the volume increases because the external pressure decreases (see Boyle's Law). At some point, the pressure inside the balloon exceeds the elastic capacity of the balloon material, and the balloon then bursts. There is a parachute attached to the instrumentation package allowing it to achieve a semi-soft landing, and they have some sort of homing device, usually, to enable them to be located and retrieved.
A balloon rises due to density differential, the density inside the balloon being less that the density outside. It's bouyancy, actually. The weather balloon, the hot air balloon, and the submarine all rise and fall on the same principle.
It is extremely desirable to retrieve these instrument packages, as they cost quite a lot to produce. More than I make in a year, that's for sure.