To Demonstrate Resonance with a set of Coupled Pendulums

Materials Required

  • Laboratory stand
  • Meter scale
  • Pendulums of different size
  • Thread

 

The Procedure 

Real Lab Procedure

  • Place two iron stands on the table about 40 cm apart from one another.  
  • Tie a half metre scale (or still better a straight strip of wood about 1.5 cm wide) between them so that it is horizontal with its face vertical and free to rotate about its upper edge. 
  • Near one edge of the scale suspend a pendulum with a heavy bob.  
  • Also suspend four or five pendulums of different lengths with bobs of relatively lower masses.  
  • Note - However, one of them should be exactly of the same length as the one with the heavy bob, as described. 
  • Let all the pendulums come to a rest after setting up the arrangement described above.  
  • Gently pull the bob of the heavy pendulum and release it so that it starts oscillating.  
  • Make sure that other pendulums are not disturbed in the process.  
  • Observe the motion of other pendulums.  

 Simulator Procedure

  • Drag the scale and drop it near the laboratory stand. 
  • Click and drag the pendulums near the scale. 
  • Click and drag the large bob downwards.  
  • Observe the oscillations of heavy pendulum and other pendulums. 
  • Click on the Inference button to see the observations. 
  • Click on the Next button. 
  • Click the correct answer for the questions displayed. 
  • Click on the Reset button to redo the experiment.

 

Observation

  • The maximum transfer of energy of motion of one pendulum to the other of the same length. 
  • In coupled resonant pendulums, the frequency of one pendulum affects the other as they both swing from the same string. These frequencies interact by transferring energy from the swing of one pendulum to the next, and back eventually to the first.