I like this idea and the lighting gives nice definition to the shape of the string a bit of balloon and the shadow gives a great feeling of the action, Although the title tells me what has happened - a baloon has popped - what my eyes tell me is a bit of broken balloon is falling to the ground. I don't feel the pop. I know how hard it must be to catch the defining moment of a balloon popping, nevertheless -this doesn't do it. Kudos for trying!
One whole balloon earlier, one already dead one now -- makes me REALLY want to see the stage in between in a motion capture. I like the shot anyhow; the falling motion is obvious as if the pop was recent, which helps with the challenge topic being met. Maybe too bright on the lighting on top -- it probably helped make a nice crisp shadow, so only 'maybe', but it's a little distracting.