Economy Resonance Tube - WA-9495


Shown with the Open Speaker and Sine Wave Generator (sold separately)


Students will have no difficulty hearing resonant frequencies from this tube. Two nested cardboard tubes with a removable inner stopper allow students to perform resonance experiments on both open and closed tubes.
Using the inner plunger tube to vary the length of the column of air within allows students to investigate the effects of length on the resonant frequencies. A measuring tape is mounted to the plunger tube to indicate the effective length.
Remove the plunger tube and an open tube of constant length remains for further investigations. Students can vary sound source frequency to investigate an open-tube resonant frequency pattern.

Suggested Activities

  • Determine lengths of the tube at which resonance occurs when the frequency is constant.
  • Determine the frequencies at which resonance occurs when the length of the tube is held constant.
  • Determine the speed of sound in air.
  • Find the relationship between closed-tube and open-tube resonant lengths.


  • A removable end cap on inner tube allows air column to act as either an "open" or a "closed" tube.
  • A metric scale on the inner tube has two rows of measurements; one indicates resonating length when the plug is in place, the other for when the plug is removed.
  • Convenient tube stands ensure that the tube does not roll off the table.


  • Outer Tube (length 1.3m; diameter 0.15m)
  • Inner Tube (Includes measuring tape and cap on one end)
  • Tube Stands (2)
  • How It Works

    Generate a pure sound wave several centimeters from the opening of tube. Vary the length of the tube or the frequency of the sound wave. When the tube is driven at resonant frequency, the sound is louder.


    Outer tube length
    • 1.3 m
    Inner tube length
    • 1.3 m
    Outer tube diameter
    • 0.15 m

    Buying Guide