======Giant Pendulum======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Conservation of Energy Pendulum
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====Summary====                   
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====Procedure====  
  - Suspend a large pendulum from the ceiling of the lecture hall.  
  - Position a ladder with a plywood backdrop behind the instructor.  
  - The instructor holds the pendulum bob against their chin while standing against the plywood.  
  - Without giving the pendulum any push, release it and allow it to swing across the room.  
  - Observe as the pendulum returns to its original position, stopping just short of the instructor’s chin.  
  - To surprise students, subtly push the pendulum during a first trial so it strikes the plywood backdrop on return.



====Links==== 
Conservation of Energy - Best demonstration Ever !! - The PhysicsMaths Wizard: 
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When a physics teacher knows his stuff !! - Lectures by Walter Lewin: 
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📄 Giant Pendulum - Stony Brook University: [[https://labdemos.physics.sunysb.edu/c.-kinematics-and-dynamics/c8.-mechanical-energy-and-power/giant-pendulum]]\\


====Variations====
  * Use a smaller pendulum version for classroom demonstrations.  
  * Record the motion with a slow-motion camera to analyze speed changes.  
  * Have a second person mark the maximum swing heights to show that the pendulum never exceeds its starting position.



====Safety Precautions====
  * Only the instructor should stand in front of the pendulum; students must stay back.  
  * Do not give the pendulum any forward push if it is released near the face.  
  * Ensure the pendulum is securely attached to the ceiling before use.  
  * Always stand with your back against the plywood so you cannot lean forward accidentally.




====Questions to Consider====
  * Why does the pendulum bob not hit the instructor on its return swing? (It cannot rise higher than its initial height due to conservation of energy.)  
  * What forms of energy are being exchanged during the pendulum’s motion? (Potential energy at the highest points and kinetic energy at the lowest point.)  
  * What would happen if the pendulum were given an initial push instead of just being released? (It would return with extra speed and could rise higher, making the demonstration unsafe.)