Coin and Feather Apparatus Free Fall Tube is designed to demonstrate free fall in a vacuum. This experiment demonstrates the coin and the feather falling with the same acceleration and striking the tube’s bottom at the same time. It shows the fact that objects of different masses fall at the same rate in a vacuum.The Coin and Feather Apparatus Free Fall Tube consists of a 90cm long and 5.5 cm in diameter plastic tube that is capped on both ends with a rubber stopper, with one end having a 1/4 NPT ball valve(stopcock) fitting for air evacuation.

When the tube is inverted under normal atmospheric pressure, students will see that the coin falls at a faster rate than the feather because of air resistance. When air in the tube is pumped out via a vacuum pump to create a vacuum in the tube, and the tube is inverted, the coin and feather in the tube will fall at the same rate because there is nothing causing resistance anymore in the tube.

Very occasionally the feather sticks at one and and must be dislodged by shaking the apparatus. A small vacuum pump (0201020060) or Laboratory High Vacuum Pump (0201020590) is required.