Have your students participate in a friendly competition, to design, build, and drop a paper helicopter with the slowest rate of descent possible. The 17 pages of pdf material includes directions, tips, prototypes, and optional aerodynamic related math challenges. Two permanent online applets are also included, one for helping students design their auto-rotators and one for teachers to check their math. There is even a very short movie showing a paper helicopter auto-rotating. Enjoy.