Alex Greathouse, left, and Mia Ball, right, launch a 2-liter bottle rocket they made as part of the Space and Rocketry course during West Virginia University at Parkersburg’s Kids’ College program.

Launching water rockets is a safe and exciting way for K-12 students to learn about the forces that determine the flight trajectory of a rocket. The body of the rocket is an empty, plastic, two-liter ...