Mrs. Taub’s fifth graders began exploring the engineering principles of the design cycle. Their first design and variables challenge was to construct an air trolley. They watched several videos explaining the principles of energy and the physics needed when creating a zip line and an air trolley. They also learned about the connection between potential and kinetic energy. After following the directions to build their air trolleys, the students took them for a trial flight on a zip line of their own construction. The variables in this challenge were the connection between different sized rubber bands, how many twists were created on the track, the speed at which each trolley flew, and the distance it was able to go. The students had fun observing the differences in each trolley’s flight.