BCIT Physics Department

Demonstration Manual

Sound and Wave Motion

DVW20.1 - Longitudinal Wave Blaster


- To mechanically generate longitudinal waves of very high amplitude.



Set up blocks and rod on the Lab Bench. Position the blocks at the marks which identify the nodes. Apply resin to the chamois.

Tap the end of the rod with the small aluminum sample to start resonance. While holding the rod at the nearest block, pull the chamois towards one end, until the original vibration is greatly amplified.

Hold the steel ruler by the fingertips and allow it to contact the vibrating end.


  1. This demo is only to be used in the physics lab.
  2. This demo requires one full lab bench.
  3. The sound level can reach painful levels.
  4. The steel ruler illustrates the power contained in the longitudinal waves,
  5. The ruler bounces away from the end of the long aluminum rod.