FREE FALL TUBE

Students may expect that lighter objects experience a lesser acceleration than heavier objects. That idea is supported by observing that when a piece of paper and a pencil are dropped simultaneously from the same height, the pencil reaches the ground first. What the students overlook is the action of aerodynamic force on the paper, which counteracts the gravitational influence. By evacuating air from the Free Fall Tube, the aerodynamic forces can be virtually eliminated as a variable in the demonstration. As a result, objects will fall with the same acceleration and reach the bottom of the tube at the same time. Consists of a plastic tube that is closed at each end by a vacuum-tight cap. The bottom cap is fitted with a stopcock for air evacuation.