If lightning can destroy trees, how come that people survive it?

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    Lightning Trees
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Discussion Overview

The discussion revolves around the phenomenon of lightning striking trees and humans, exploring the reasons why trees may be destroyed while some people survive lightning strikes. The scope includes theoretical explanations, biological responses, and the physics of electricity in living organisms.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • Some participants propose that the size difference between trees and humans affects the outcome of lightning strikes, with larger structures like trees being more susceptible to destruction.
  • Others argue that the resistivity of the structures plays a significant role, noting that trees explode due to rapid boiling of water inside them, while humans may experience different electrical effects due to their composition and size.
  • A participant mentions the 'skin effect' in conductors, suggesting that more current may flow through a tree than a human due to differences in structure and conductivity.
  • Another viewpoint highlights that not all trees are destroyed by lightning, as some may catch fire instead, and discusses the variability in human survival based on the current path through the body.
  • One participant questions how often people are directly struck by lightning compared to trees, suggesting that trees may absorb the full impact while humans are often indirectly affected.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the effects of lightning on trees versus humans, with no consensus on the primary reasons for the differences in outcomes.

Contextual Notes

There are unresolved aspects regarding the specific conditions under which trees and humans are struck by lightning, including the variability in current paths and the effects of different types of lightning strikes.

Who May Find This Useful

Individuals interested in the physics of electricity, biological responses to electrical shocks, and the environmental effects of lightning may find this discussion relevant.

jetwaterluffy
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I mean, trees are a lot bigger than people, aren't they?
 
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Many people don't survive, of course!

I think it must be something to do with the difference in size and the resistivity of the structures. Trees explode because the water inside them boils rapidly and produces steam. This is because the produce of Volts and Current (defined by the overall length and the resistance) - the Power Dissipated - is high enough to boil the relatively small amount of water in the tree. (Less water implies a higher resistivity)
For an animal body, the volts are lower (it's a shorter structure and the voltage relates to the Field times the length) and the resistance is much lower (mostly water with dissolved salts). This suggests to me that there will be less actual Power involved; not enough to actually boil your insides.
There is also the 'skin effect' which determines the depth at which a pulse of current or and AC signal passes through a conductor. It stays just on the surface of a very good conductor. I think, therefore, that there will be more current flowing through the inside of a tree than of a human.

Otoh, plants don't have a delicate nervous system and, if they don't actually explode, they tend to stay alive and produce green shoots from some of the shattered stump. Animal hearts can just stop from the electric shock.
 
All that is true, but trees are not always destroyed. A hot strike will explode a tree as you say, but a cool strike will set it on fire. We can survive a very small current thru the heart, or sometimes a very large current. In the band in between we are dead. They have different theories as to why that is. Depending on the actual path the lightning takes, the actual current thru the heart can be high, low, or the fatal in between. In most cases of human strikes, the human is only a small part of the path as the air around us is ionized and becomes very conductive.
 
How often are people DIRECTLY struck by the main path of the lightning and not an "offshoot" path? Perhaps the difference is that trees commonly take the full brunt of the strike since they are taller and wider while people are usually only indirectly struck?
 

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