Plasma ball electric shock mystery

Click For Summary

Discussion Overview

The discussion centers on the phenomenon of electric shock (or lack thereof) when touching a plasma ball, exploring the underlying physics and mechanisms involved. Participants examine the properties of the plasma ball, the role of glass as an insulator, and the interaction between the human body and the electric field generated by the device.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • Some participants note that the glass of the plasma ball acts as an insulator, which may prevent electric shock.
  • Others propose that the attraction of the plasma threads to a hand is due to the parasitic capacitance introduced by the hand when it touches the glass globe.
  • One participant suggests that the human body, being conductive, can accept RF energy more easily than the surrounding dielectric material, creating a favorable discharge path.
  • Another point raised is that electric shock is avoided because the current is limited by the internal resistance of the voltage source in the plasma ball.
  • It is mentioned that a small air gap between the globe and a hand could lead to a discharge, which might be perceived as a hissing noise and the smell of ozone.
  • A participant notes that placing aluminum foil on the globe could result in a small shock to the finger.

Areas of Agreement / Disagreement

Participants express various hypotheses regarding the lack of electric shock and the behavior of the plasma threads, indicating that multiple competing views remain without a clear consensus.

Contextual Notes

Some claims depend on specific conditions such as the presence of air gaps or the material properties of the human body and the plasma ball. The discussion does not resolve the underlying mechanisms or assumptions regarding the electrical properties involved.

Herbert Cheung
Messages
2
Reaction score
0
Plasma ball has a high voltage. Why don't we get an electric shock when we touch it?
 
Physics news on Phys.org
Herbert Cheung said:
Plasma ball has a high voltage. Why don't we get an electric shock when we touch it?
Glass is an insulator. :smile:
 
  • Like
Likes   Reactions: CWatters
Oic @berkeman
So why is the plasma thread attracted to my hand when we touch it?
 
Herbert Cheung said:
Oic @berkeman
So why is the plasma thread attracted to my hand when we touch it?
I believe it's because of the extra parasitic capacitance that your hand presents when you touch the glass globe, but I'm not sure. Can you post links to the reading you've been doing about them? Have you seen if Wikipedia has a good introductory article on them? :smile:
 
Last edited:
It's actually a very interesting question. The answer seems to be that your finger gets RF energy.

https://en.wikipedia.org/wiki/Plasma_globe said:
Placing a finger tip on the glass creates an attractive spot for the energy to flow, because the conductive human body (having non-ohmic resistance of about 1000 ohms at room temperature) is more easily polarized than the dielectric material around the electrode (i.e. the gas within the globe) providing an alternative discharge path having less resistance. Therefore, the capacity of the large conducting body to accept radio frequency energy is greater than that of the surrounding air.
 
Herbert Cheung said:
Why don't we get an electric shock when we touch it?

You do not get an electric shock because the current is limited by the internal resistance of the voltage source.
If there is a small air gap between the globe and your hand, a discharge may develop in that gap, perceived by a hissing noise and the odor of ozone. If you put a piece of aluminium foil on the globe, your finger may receive a small shock.

plasmaball.png
 

Attachments

  • plasmaball.png
    plasmaball.png
    1.5 KB · Views: 1,021
Last edited:

Similar threads

Undergrad Why Do I Get Electrically Shocked by Metal Objects?
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Plasma ball radio-frequency energy
  • · Replies 3 ·
Replies
3
Views
3K
Graduate Skin effect and electric shock question
  • · Replies 2 ·
Replies
2
Views
2K
High School Coil + zinkplate + copperplate + 9V battery = shock
  • · Replies 2 ·
Replies
2
Views
1K
Undergrad Potential Difference and electric shock
  • · Replies 10 ·
Replies
10
Views
5K
High School What materials produce higher levels of static electricity?
  • · Replies 1 ·
Replies
1
Views
2K
High School Static Electricity: Can You Still Get a Shock Off the Ground?
  • · Replies 4 ·
Replies
4
Views
2K
Undergrad Do birds on transmission lines experience electric shock?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad Can Concrete Conduct Enough Electricity for a Shock to Be Felt?
  • · Replies 1 ·
Replies
1
Views
2K
High School The voltage between two points
  • · Replies 11 ·
Replies
11
Views
2K