Here is a sequence of photos we took during a pyrotechnic balloon drop. The difference between this sort of drop and a traditional balloon drop is that with this method, smaller balloons are dropped from a larger balloon rather than a net or a bag. The large balloons are attached to pyrotechnic charges that burst the balloons when they are fired. The bursting of the large balloon creates a nice spread by forcing the smaller balloons outwards rather than straight down.
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This 5' white balloon was filled with 16" burgundy balloons, then brought up to the ceiling in preparation for being burst.
As the large balloon bursts, the smaller balloons start out in a cluster.
The force of the large balloon's explosion propels the smaller balloons in all directions.
The small balloons start to drift slowly downwards.
Finally only a few are left in the air.