======Van de Graaff Human Chain======


<WRAP right box>
**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
\\
**Categories:** {{$demo.categories}}
\\


**Alternative titles:** Passing the Charge
</WRAP>

====Summary====                   
{{$demo.summary}}



====Procedure====  
  - Place the Van de Graaff generator in an open area with space for several volunteers.  
  - Have one volunteer stand on an insulating platform and place their hand on the generator’s dome.  
  - Ask several other volunteers to form a chain by holding hands with the first person, all being insulated from the floor (e.g. on tables or plastic mats).  
  - Turn on the generator and allow charge to build up.  
  - Have the last person in the chain carefully bring their free hand near a grounded rod or a metal object.  
  - Observe the spark as the chain discharges.  
  - After the demonstration, turn off the generator and discharge the dome with the grounding rod before anyone lets go.



====Links==== 
Physics -2018 - Van der Graaf chain - Clink's Class: 
{{youtube>HB7nNMzr9rg?}}\\

Physics 2021 - (2nd period) - The Big Shock - Clink's Class: 
{{youtube>QJbtSgfEEjE?}}\\


====Variations====
  * Try different numbers of people in the chain to see how far the charge can travel.  
  * Perform in a darkened room to make sparks more visible. 
  * Compare the effect with everyone standing on insulating mats versus standing on the floor.

====Safety Precautions====
  * Always discharge the dome with a grounding rod before anyone breaks the chain.  
  * Ensure participants are not wearing or carrying sensitive electronics (phones, watches, hearing aids, pacemakers).  
  * Warn participants that small shocks and sparks may be startling.  
  * Use only healthy volunteers and avoid individuals with heart conditions or electronic medical implants. 





====Questions to Consider====
  * How does the charge travel from the generator through the human chain?  
  * Why does the spark appear at the last person when they approach a grounded object?  
  * What role does the insulating platform play in this demonstration?  
  * How is this related to how electricity flows in circuits?  
  * What similarities exist between this demonstration and natural lightning discharges?