Then, the grand finale. One student in the group was to hold the bottle and another was to launch the balloon by pulling it off the bottle.
The design flaw? 4 kids to a group and all 4 wanted to launch the balloon. Mayhem. Then the balloons started to fly and then it got crazy nuts. I'm a tad traumatized and I'm not sure if her saintly teachers will permit me back in, but it was definitely fun.
Here's a copy of the activity: tr.im/dry_ice