Does lightening cause a form of cavitation?

  • Context: High School 
  • Thread starter Thread starter THORPE
  • Start date Start date
  • Tags Tags
    Cause Form
Click For Summary

Discussion Overview

The discussion centers around the question of whether lightning can cause a form of cavitation in air, similar to that which occurs in liquids. Participants explore the mechanisms involved in lightning and its effects on air, including the generation of sound (thunder) and the physical processes at play.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if lightning causes cavitation in air, suggesting that its rapid movement might have similar effects to cavitation in fluids.
  • Another participant argues that cavitation involves bubble formation, which typically requires a liquid medium, and expresses uncertainty about the existence of plasma bubbles.
  • A third participant clarifies that while the phenomenon is not cavitation in the traditional sense, the rapid heating and subsequent cooling of air due to lightning does lead to rapid expansion and collapse, which contributes to the sound of thunder.
  • A fourth participant cites a Wikipedia entry explaining that the superheating of air by lightning creates a shock wave due to rapid pressure changes, emphasizing the differences between cavitation in fluids and the effects of lightning.

Areas of Agreement / Disagreement

Participants generally agree that the phenomenon associated with lightning is not cavitation as traditionally defined, but there are differing views on the similarities and the underlying processes involved. The discussion remains unresolved regarding the specific nature of the effects of lightning on air.

Contextual Notes

Participants note limitations in understanding the relationship between lightning and cavitation, particularly regarding the definitions and conditions necessary for cavitation to occur. There is also uncertainty about the existence of plasma bubbles and how they relate to the phenomenon being discussed.

THORPE
Messages
41
Reaction score
0
Does lightning cause cavitation of air much like in a normal fluid?

It moves through the air so fast it has the same effect and then we hear thunder as a result?
 
Science news on Phys.org
Cavitation is the creation of bubbles that release energy when they pop. I don't think just air can form bubbles by itself, it would need a liquid to contain it. The lightning is ionizing the air and heating it to a plasma. I don't know if there are such thing as plasma bubbles and so I don't know the answer to your question.
 
Last edited:
Dragon is correct, that this cannot be cavitation the way we normally understand the term. But it is something similar. With such rapid heating of the air, you have very rapid expansion. That is followed by very rapid cooling and a collapse of the air back to something close to its original volume. This is what makes the noise.

In cavitation, you have a rapid expansion of a gas bubble, followed very quickly by its collapse. Similar, but different.
 
From Wikipedia:
"Because the electrostatic discharge of terrestrial lightning superheats the air to plasma temperatures along the length of the discharge channel in a short duration, kinetic theory dictates gaseous molecules undergo a rapid increase in pressure and thus expand outward from the lightning creating a shock wave audible as thunder. Since the sound waves propagate, not from a single point source, but along the length of the lightning's path, the sound origin's varying distances from the observer can generate a rolling or rumbling effect."
http://en.wikipedia.org/wiki/Lightning

Cavitation in fluids is quite different from lightning. You may Google it to learn more.
 

Similar threads

Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 81 ·
3
Replies
81
Views
9K
Replies
1
Views
3K
  • · Replies 39 ·
2
Replies
39
Views
7K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 29 ·
Replies
29
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
8
Views
8K