f a tuning fork is held over an enclosed air column, whose length is adjustable, the sound wave generated by the tuning fork will be amplified at a resonance point. A plunger is used to vary the length of the column. The bottom of the air column, at the top of the plunger, is the closed end of the tube and thus a node for a standing wave. The open end of the air column is an antinode. The first resonance point occurs when the distance between a node and an antinode is /4