First part of the balloon question asked why the rocket toy continued to travel upward despite the balloon being fully deflated.


This was due to the fact that the toy still possessed Kinetic energy at that point of time. Kinetic energy of the air escaping from the balloon was converted to kinetic energy of the toy. The kinetic energy of the toy was then converted to Gravitational Potential energy as the toy moved up. Due to air resistance, some of the kinetic energy is also converted to heat.

Second part of the question asked why the balloon darts around when released. If you make use of the context given in part one, the main difference is that the balloon is no longer encapsulated inside a solid with definite shape. Without the toy rocket holding the balloon in a fixed position, the air escaped from the balloon in different direction, causing it to dart around.