BCIT

BCIT Physics Commons

This site is operated by the Physics Department

DVW18.1 Interference Tubes

Objective:

– To show that two sound waves of the same frequency cancel out if one has to travel 1/2 wavelength further than the other.

Apparatus:

  • Custom PVC interference tube loop
  • Stand, 3-fingered clamp
  • Function generator, Wavetek
  • Speaker (University Sound model 1D30C-8)
  • Banana leads, two
  • BNC/Banana adapter

 

Method:

Set the frequency generator to generate a 2.1 KHz sine wave. Fine tune the frequency control to attain maximum sound output, with the top loop retracted. The sound is split into two paths which re-combine at the output. If the top loop is lengthened by 1/2 wavelength, the two sound waves interfere and very little output is heard.

Note:

The effect can be demonstrated to an entire class at once.

 

Interference Demo: Red-Neck Trombone – Video Created at Utah State University by Professor Boyd F. Edwards and assistants.

Quick Links

  • Home
  • Members of Our Department
  • Physics Demonstrations Library
  • What’s New in Physics
  • Student Resources

Copyright © 2025 · BCIT · BCIT Commons