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Author Topic: Is it possible to make a human faraday cage?  (Read 902 times)

Offline thedoc

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Is it possible to make a human faraday cage?
« on: 20/06/2016 11:50:02 »
Ste asked the Naked Scientists:
   Is it possible to make a human faraday cage. What I mean is to block electromagnetic signals from penetrating yourself by applying a charge and creating a null field inside. How could this be done and to what extent without effecting internal functioning of the body?
What do you think?
« Last Edit: 20/06/2016 11:50:02 by _system »


 

Offline PmbPhy

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Re: Is it possible to make a human faraday cage?
« Reply #1 on: 20/06/2016 18:46:48 »
Ste asked the Naked Scientists:
   Is it possible to make a human faraday cage. What I mean is to block electromagnetic signals from penetrating yourself by applying a charge and creating a null field inside. How could this be done and to what extent without effecting internal functioning of the body?
What do you think?
Yes. If not then there's be no such thing as a Faraday cage. There's one such cage at the Boston Museum of Science. The person who runs the lightning show stands inside of it. The lightning zaps the outside of the cage where the man places his hand inside of it. It's cool to watch.
 

Offline Bored chemist

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Re: Is it possible to make a human faraday cage?
« Reply #2 on: 20/06/2016 20:09:09 »
You can certainly block any external sources of fields.
Since earth conducts electricity (not very well, but...) being in a cave is being in a Faraday cage. A car is a pretty good one too.

However there are still the tiny fields produced by the body's own electrical impulses.
 

Offline evan_au

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Re: Is it possible to make a human faraday cage?
« Reply #3 on: 20/06/2016 22:39:33 »
A Faraday cage works by surrounding an object with a highly conductive mesh - usually made of metal. It is easy for current to flow through the metal, leaving a region inside which has no overall electric field.
See: https://en.wikipedia.org/wiki/Faraday_cage

Quote from: Ste
by applying a charge and creating a null field inside
The Faraday cage does not require a charge to be applied; it works perfectly well with an uncharged cage.

Quote
block electromagnetic signals from penetrating yourself
Metals block electromagnetic field penetration because any electromagnetic radiation sets up an opposing current in the electrons, which results in the incident light being reflected at the opposite angle to the angle it approached (the law of reflection).

Unfortunately, the slightly-salty water that makes up our skin cells is not very conductive. It will slowly absorb electromagnetic energy that penetrates our skin. The depth to which much of the radiation penetrates is described as the skin effect depth; in seawater its about 0.25m at 1MHz. The skin depth is proportional to √f, so radio waves at 1 GHz would penetrate less than 1cm into seawater.

Unfortunately, the cytoplasm of cells is less conductive than seawater, and the non-conductive cell walls means that it is effectively an insulator for wavelengths much larger than a single cell (eg for the wavelengths emitted by a mobile phone). So radio wavelengths will penetrate our bodies to a fair depth.
See: https://en.wikipedia.org/wiki/Skin_effect#Material_effect_on_skin_depth

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to what extent without effecting internal functioning of the body?
Provided the cage was outside the body, it wouldn't do you any immediate harm from a medical viewpoint.
  • Humans need some sunlight to produce vitamin D, but that won't bother you for a month.
  • Humans need human contact - this would be like a solitary confinement cell, which might bother you after a few hours.
  • We need to breathe - but a few airholes don't cause any real problems.
  • Military communications equipment is often used inside a Faraday cage designed to exclude all external electromagnetic radiation, apparently without any ill effects for the operators.
  • I think the most severe impact on the younger generation is that texting, facebook, snapchat and twitter don't work inside a Faraday cage.
 

Online jeffreyH

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Re: Is it possible to make a human faraday cage?
« Reply #4 on: 21/06/2016 22:08:03 »
That Faraday geezer sound like such a party pooper. There may be a teenage rampage.
 

Offline Colin2B

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Re: Is it possible to make a human faraday cage?
« Reply #5 on: 22/06/2016 00:05:37 »
Was the questioner thinking of turning the body itself into a faraday cage, perhaps by painting with a metallic coating a'la goldfinger?
 

Offline syhprum

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Re: Is it possible to make a human faraday cage?
« Reply #6 on: 22/06/2016 08:51:57 »
Don't forget to leave a small area at the base of the spine uncovered !
 

Offline Colin2B

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Re: Is it possible to make a human faraday cage?
« Reply #7 on: 22/06/2016 08:57:15 »
Don't forget to leave a small area at the base of the spine uncovered !

Definitely.

I'm told this is a myth, but I don't talk about it so as not to spoil the legend http://www.timelessmyths.co.uk/gold-finger-actresses-death-from-paint.html
 

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Re: Is it possible to make a human faraday cage?
« Reply #7 on: 22/06/2016 08:57:15 »

 

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