Ashley Cooper's fifth-grade students shouted countdowns and excitedly launched five different homemade rockets into the sky at the Heathcote School on Wednesday, capping a study of rocketry and science in front of an audience of classmates and parents.

This was actually the students' third launch of their rockets, which have been redesigned for each launch in an effort to make them more aerodynamic and lightweight.

The students designed and built their rockets out of a combination of sturdy paper, cardboard and styrofoam. They used research and information from each launch to revise their designs, with most groups changing their fin and nose cone designs dramatically over the course of their launches, after learning more about drag, balance and what it takes to be aerodynamic.

The launcher, an improvised bicycle tire pump, used air pressure as thrust to propel the rockets upward. Each group pumped the air pumper to the same PSI level of 50.

Ms. Cooper's students worked in teams on their rockets, competing in a friendly way for the highest launch into the fall sky. The teams -- NAJC, Da Humble Rockets, Fantastic Flyers, Space Jammers, and Shooting Stars -- were divided into those who got to press the launch button, those who yelled the countdown, and those who had to retrieve rockets after they were shot into the air.

No one was assigned to scream, or to carry their friends across the field in victory. That just happened organically.