Transient one‐dimensional flows have been produced by accelerating a piston in a gas‐filled tube. Accelerations of the order of 2.5×104m/sec2produced shocks within 5 m of the initial piston position. The piston was propelled pneumatically. Shocks formed at the head and in the interior of the compression waves. By optically detecting the piston and shock positions and recording the corresponding times on a rotating drum chronograph with microsecond accuracy, the properties of the compression wave and resulting shock were determined. The formation and growth of shocks were calculated from the compression wave measurements using the method of characteristics and the assumptions employed by Chandrasekhar and Friedrichs. The observed and calculated shock properties were in reasonably good numerical agreement. Consistent lagging of the observed behind the calculated shock positions (order of 0.05 m at 5 m from initial piston position) is attributed to the interaction of the flow with the tube walls.