iReport — One of the most  interesting points of any high altitude balloon flight is the moment the balloon bursts and begins its chaotic descent earthward. Here engineering students at the  University of Southern Indiana in Evansville, IN have installed  a high definition video camera looking upward at their high altitude balloon.  The balloon carries a string of experimental pods.  Between the pods and the balloon is a parachute. As the balloon rises the air density gets thinner and thinner allowing the balloon to expand and eventually burst.  In this case the balloon burst at just over 90,000 feet. Because the air is so thin at this point, the parachute cannot slow the pods, so they fall rapidly and chaotically, thus the name, post burst chaos. Eventually the parachute slows the pods in the denser air of the lower atmosphere. In the background you can hear a siren, which was placed on board one of the pods to help in locating them after landing.  Even in the thin air the siren and the sound of the burst can be heard. The flight took place on Saturday October 24, 2009.