3A40.XX U-Tube Oscillator




A U tube is filled 2/3 full of water and plugged on one end. A rubber bulb is used to pump air into the plugged end, creating oscillations. As the large oscillations damp out, the miniscus continues to oscillate.



  • [1] Glass U tube
  • [1] Ring stand
  • [2] Ring stand clamps
  • [2] 3 finger clamps
  • [1] Block of foam
  • [1] Rubber stopper
  • [1] Rubber bulb
  • Rubber tubing
  • Coloured water

Classroom Assembly

  1. Place ring stand on lectern shelf.
  2. Place foam block on ring stand.
  3. Attach 3 fingered clamps to ring stand using ring stand clamps.
  4. Attach U tube to ring stand using 3 fingered clamps.
  5. Attach bulb and rubber tubing to U tube.
  6. Fill U tube 2/3 full with coloured water.
  7. Plug end to be pumped with rubber stopper.

Important Notes

  • Oscillation of the miniscus can only be seen close-up or using a video camera.


  1. Pump the water in the U tube using the rubber bulb.
  2. Discuss the oscillation of the water.
  3. As the large oscillations damp down, point out that the miniscus continues to oscillate.


Additional Resources


  • PIRA 3A40.XX


  • Don't attempt this at home!

Last revised

  • 2018


Related AV

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.