Driven String Demonstration

 

This demonstration shows the different modes of resonance, making standing waves of order 1, 2, ... n on the string with a function generator.

Driven StringDriven String

Used in Lab:

This demonstration is NOT used in any lab.

Equipment:

  • Two Lab Stands                                       Location: Demo Rm Hallway opposite Shelf M
  • String                                                Location: Demo Rm Shelf V
  • Pasco Mechanical Vibrator               Location: Demo Rm Shelf L
  • Function Generator                          Location: Demo Rm Shelf I      
  • Lab jack                                           Location: Demo Rm Shelf W
  • Electric cables                                 Location: Demo Rm Shelf V
  • Optional: Strobe light                       Location: Shelf I           
     

Setup Instructions:

  • Tie the string to one lab stand
  • Thread the other end through the mechanical vibrator, propped on a lab jack for height
  • Tie the loose end to the second lab stand
  • Connect the function generator to the mechanical vibrator
  • Turn on and adjust the frequency to find resonance

Apparatus Notes:

You may need an amplifier in series with the function generator.
Addition of the strobe light: adjust the strobe light to slightly different frequency than the string so that it will appear that the wave on the string is oscillating very slowly


Safety Information: Strobe lights may cause a health risk to students. Inform students of intent before using it.
JHA