Capacitor+Grounded Plate+AC Current?

  • Thread starter Thread starter pickle123
  • Start date Start date
  • Tags Tags
    Current
Click For Summary

Discussion Overview

The discussion revolves around the phenomenon observed during a demonstration involving a pickle connected to an AC electrical outlet. Participants explore the reasons behind the consistent ignition of the pickle at the end connected to the "hot" terminal, questioning the implications of alternating current and grounding in this context.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants express confusion about why the fire starts at the "hot" end of the pickle, given that it is an AC source where both sides are effectively the same.
  • Others suggest that the connection methodology might favor one side, questioning whether the professor connects the ground to a specific side of the pickle.
  • A participant mentions that the professor's explanation involves modeling the pickle as a resistor in parallel with a capacitor, with one end grounded, but expresses uncertainty about this model.
  • Some participants discuss the role of electrode placement and connection order in determining where the ignition occurs, suggesting that the last connected electrode might be where the burning starts due to higher resistance.
  • There is a contention regarding the appropriateness of modeling the pickle as a capacitor with a resistor, with some arguing that the electrodes and the pickle's juice are conductive, which complicates this model.
  • One participant notes that the glow observed during the demonstration is not purely thermal, indicating a more complex interaction at play.
  • Another participant mentions that the direction of energy flow may not change even though current direction does, raising questions about the implications of this for the observed phenomenon.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the reasons behind the ignition of the pickle or the validity of the proposed models. Multiple competing views remain, with ongoing debate about the underlying physics.

Contextual Notes

Participants express various assumptions about the setup and electrical properties involved, including grounding effects, electrode placement, and the nature of AC current. There are unresolved questions regarding the applicability of certain models to the phenomenon observed.

  • #31
A clue to the operating principle of the pickle light emitter might be found by examining why its emission eventually ceases; the lighted region seems to jump about and emission starts and ends as suddenly as though a switch were thrown, and this is not consistent with the glow emitted due to a sizeable body being heated to incandescence. In fact, a consensus among writers is that the light is the sodium spectrum, and arises from the high salt content in the pickled cucumber.
 
Engineering news on Phys.org
  • #32
There is no doubt that the glow is not heat glow. Did you read the paper I linked to? It is proposed there is plasma arcing within the pickle.
I think it is plausible that the side of the pickle to actually burn first would be the same side that first glows. I've seen the small side glow, and the fat side glow. I have no theory founded in electronic or physics theory (such as the proposed idea that the energy flow in an AC circuit has a "direction" because of the difference between neutral and ground) that would support the professors claim that "the same side always burns first".
 
  • #33
I agree with those who say it is the order of connection, or the resistance right at the point of connection. It cannot be anything else. The big problem is why the resistance would be lower at one connection point. It may be that something is distributing the connection at the grounded neutral or "cold" terminal causing a larger cross sectional area (and less resistance) for that termination, or something is concentrating current in a smaller cross sectional area at the "hot" terminal causing the same current through a smaller area (more I^2 R heating from more resistance around that termination). It cannot be anything else.

This reminds me of a clock. My 120V electric motor ship clock was subjected to a lightning surge that shorted near one end of the winding to the motor frame. This made it sensitive to stray capacitance or leakage to ground. If I installed the plug one way, it ran forward. If I installed the line plug the other way, it ran backwards. I had an unbelievable amount of fun with that clock, until I discovered the clock face was at 90 volts or 30 volts to ground, depending on insertion. The pickle, however, cannot be like the clock because impedance levels are far different. It cannot be sensitive to displacement currents via capacitance like the high impedance clock motor.
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 8 ·
Replies
8
Views
1K
  • · Replies 26 ·
Replies
26
Views
3K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 19 ·
Replies
19
Views
6K
  • · Replies 79 ·
3
Replies
79
Views
7K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
24
Views
3K