Moving while lighting, will be induced current in me?

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Discussion Overview

The discussion centers around the question of whether a person moving during a lightning storm can have an induced current in their body, and how such a current would flow if it occurs. Participants explore the implications of lightning strikes, the nature of induced currents, and the conditions under which a person might be harmed.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question the clarity of the original question regarding "moving while lightning" and seek clarification on the intended meaning.
  • There is a proposal that a lightning storm could induce a current in a person on the ground, but the specifics of how this occurs and the necessary conditions are debated.
  • Some argue that lightning strikes do not last long enough for a person to move significantly, suggesting that movement is not necessary for current induction.
  • It is noted that electrical circuits do not need to be closed for current to flow, which leads to discussions about potential differences and the behavior of charges during a lightning strike.
  • Participants discuss the concept of equipotential lines and how standing position relative to a lightning strike can affect the likelihood of injury.
  • There is mention of the nature of lightning, including the charge distribution in clouds and the ground, with some participants explaining the difference between negative and positive lightning.
  • Questions arise about the necessity of movement to induce current and whether standing on one leg would prevent injury.

Areas of Agreement / Disagreement

Participants express differing views on whether a person can be harmed by induced currents during a lightning storm, with some asserting that currents are not significant in the human body while others suggest that conditions can lead to injury. The discussion remains unresolved regarding the specifics of current induction and the conditions that lead to harm.

Contextual Notes

Participants highlight limitations in understanding the conditions under which currents are induced and the role of movement versus standing still. There are also unresolved questions about the definitions of current and voltage in this context.

Physicsissuef
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ometimes people say that if you moving while lighting, there will be current induced in you, and you'll die, is it correct, and if so how the electrical circuit is closed? (They say if lighting strikes near you, from the electrical field, if you move, there will be induced current in you)
 
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The title and first sentence don't make any sense to me. What does "moving while lightning" mean? Is English your native language?
 
What he presumably means is; Will a lightning storm induce, in a person who is moving on the ground, a current sizeable enough to kill them? If so, to where does this current flow?
 
dst said:
What he presumably means is; Will a lightning storm induce, in a person who is moving on the ground, a current sizeable enough to kill them? If so, to where does this current flow?

Yes that's was the point. Thanks for correcting me. Actually the question is: "Will a lightning storm induce, in a person who is moving on the ground, a current? If so, how the electrical circuit will be closed?"
btw-English is not my native language.
 
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Here is some http://img81.imageshack.us/img81/5092/85498790am6.jpg"
 
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Physicsissuef said:
Yes that's was the point. Thanks for correcting me. Actually the question is: "Will a lightning storm induce, in a person who is moving on the ground, a current? If so, how the electrical circuit will be closed?"
btw-English is not my native language.

No. Everyday observation should convince you this is not so.
 
Physicsissuef said:
Yes that's was the point. Thanks for correcting me. Actually the question is: "Will a lightning storm induce, in a person who is moving on the ground, a current? If so, how the electrical circuit will be closed?"
btw-English is not my native language.

First, lightning strikes do not last long enough for you to move any significant distance.
However, you don't need to move since the lightning itself is moving charges.
So yes, a current will be induced in nearby objects, like you.
Electrical circuits do not need to be closed, in the sense that you are thinking of, for a current to flow.
 
NoTime said:
First, lightning strikes do not last long enough for you to move any significant distance.
However, you don't need to move since the lightning itself is moving charges.
So yes, a current will be induced in nearby objects, like you.
Electrical circuits do not need to be closed, in the sense that you are thinking of, for a current to flow.

Do I must move, so current will be induced, or I can just stand?
 
You can just stand.
 
  • #10
NoTime said:
You can just stand.

What will happen, if I stand? I mean how the current is induced?
 
  • #11
Moving charges (the electrons in the lightning) generate a magnetic field.
The changing magnetic field, as the lightning starts and stops, moves electric charges.
The same principal that the transformer is based on.
 
  • #12
NoTime said:
Moving charges (the electrons in the lightning) generate a magnetic field.
The changing magnetic field, as the lightning starts and stops, moves electric charges.
The same principal that the transformer is based on.

Yes, that was my point. But in the transformer there is electrical circuit closed. In the lighting case, there isn't any closed circular loop.
 
  • #13
Without a closed circular loop you have potential differences. In some ways you are a battery.
 
  • #14
In the normal sense of currents, nearby lightning strikes (say 30 m away) do not induce currents in a human body. There are currents induced in fences and wires which are metallic conductors but not in the body (unless you want to define small dislocations of ions as currents).
 
  • #15
TVP45 said:
In the normal sense of currents, nearby lightning strikes (say 30 m away) do not induce currents in a human body. There are currents induced in fences and wires which are metallic conductors but not in the body (unless you want to define small dislocations of ions as currents).

If I am close (let's say 10 meters) and the lighting strikes, will current be induced in me from the magnetic field, and how the electrical circuit will be closed?
 
  • #16
It would be impossible to answer all the "what-if"s about this situation. In general, you will not see a measurable current in the body. You do not need a closed circuit in order to have a current. And, to be more correct, it is not the current that is induced in such a case, but the voltage.

Is there a point to your question? Perhaps that might be more illuminating.
 
  • #17
TVP45 said:
It would be impossible to answer all the "what-if"s about this situation. In general, you will not see a measurable current in the body. You do not need a closed circuit in order to have a current. And, to be more correct, it is not the current that is induced in such a case, but the voltage.

Is there a point to your question? Perhaps that might be more illuminating.
I do not need a closed circuit in order to have current, please explain me how?
 
  • #18
A lighting strike creates a very large potential gradient in the Earth around it. If you are standing facing the strike then chances are good that your feet will each be on the same equipotential line, and no harm will come your way.

On the other hand if you are standing such that the strike in on your left or right chances are good that your feet will NOT be on equipotential lines and you will be come a conductor. The current path would then be in one leg and out the other, this can cause potentially fatal injuries.

The case of a lighting strike is a good example of when the Earth will NOT be at zero potential.
 
  • #19
Integral said:
A lighting strike creates a very large potential gradient in the Earth around it. If you are standing facing the strike then chances are good that your feet will each be on the same equipotential line, and no harm will come your way.

On the other hand if you are standing such that the strike in on your left or right chances are good that your feet will NOT be on equipotential lines and you will be come a conductor. The current path would then be in one leg and out the other, this can cause potentially fatal injuries.

The case of a lighting strike is a good example of when the Earth will NOT be at zero potential.

So the Earth will gain potential from the lighting? I mean when lighting strikes, the protons are going up, and the electrons down. So in the air high up, there is build of positive charge (+) and on the ground build of negative charge (-), right?
 
  • #20
Forget about the protons, only electrons need be considered.
 
  • #21
Physicsissuef said:
So the Earth will gain potential from the lighting? I mean when lighting strikes, the protons are going up, and the electrons down. So in the air high up, there is build of positive charge (+) and on the ground build of negative charge (-), right?

Most lightning is what is called negative lightning where the clouds become negatively charged on the bottom and the Earth below becomes positively charged. The stroke usually proceeds down from the cloud and, as it nears the earth, a positive streamer may rise to meet it.

A small percentage of lightning is positive where the clouds are positively charged on the bottom and the Earth below negatively charged. So-called heat lightning which occurs at a distance from a storm is often this.

Integral makes an excellent point. If you are caught in the open during a lightning storm, it is important to crouch as low as possible with feet together (the bird on a wire low potential trick).
 
  • #22
Physicsissuef said:
I do not need a closed circuit in order to have current, please explain me how?

It's easy. Most science students have seen it dozens of times. Many non-science students have seen it numerous times. I'll leave it to you to think about.
 
  • #23
Is it possible that I will not get injury, if I am standing on one leg? I can't understand, why while standing I will not get "shock", is it because of the fact that I need to move among magnetic field to induce current in me, like in transformer?
 

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