The kids particularly enjoy these experiments in hot weather since everybody gets wet as the air pressure expels water from the bottle rocket during the launch. We have established launch protocols to ensure that safety standards are maintained and to add realism to the rocket launches. Those protocols require and limit launch crews to three people. Two of the crew load the water according to experiment specifications, they also load the rocket onto the launcher. The launch commander inspects the rocket connection before giving the approval to charge the bottle with air pressure.
Air pressure is applied to the rocket after everyone is warned that a bottle is about to be charged.
The launch commander then assumes the trigger position, and after surveying the area begins to count down in one second increments from five to one and launch. The other two crew members are responsible for retrieving the rocket and the payload if there is one on the launch. One particular seventh grade class was precocious. They were the school leaders in academics, sports, after school activities, and every activity they were involved in. They were a group of kids who had mainly been together since the third or fourth grade, and in general were really in control of things at school.