4B10.70 Ruchardt’s Tube
A container of gas has a long glass tube emerging from the top. A ball bearing, exactly fitting the precision glass tube, is dropped into it. The ball bounces on the gas below, compressing it adiabatically on the downswing and letting it expand adiabatically on the upswing. The period of the oscillations of the bouncing ball is directly related to the γ of the gas and the geometry of the system.
Location: tube D4-3, Bottle D4-5
Original paper: Physikalische Zeitschrift XXX,1929
American Journal of Physics Vol. 69, No. 11, pp. 1205–1211, November 2001 from the authors site