Ashles said:
No I think you've got this wrong. Just because nerves in our body use electric current as signals does not mean that a nearby electric source will effect them. We are insulated from the electricity so it does not effect us any more than when we grasp an insulated power cable can we get electrocuted or detect the current flowing.
Well, i'm not wrong, i'm just pointing at a minor and irrelevant, but nonetheless true detail.
Any current causes a electromagnetic field according to Maxwells laws, which mainly relate field strength to current strength and distance and material in between.
A change in the electromagnetic field inside an object can cause a current inside the object, depending on object parameters.
So if you have a copper wire and it is inside a changing em field or you move it through a constant, but not homogenous em field, the em field inside the copper wire will change and a current will be induced. This is how antenna work.
Inside an insulator there will be no current, only a slight shifting of electrons inside the atoms, so an insulator is very bad or even useless, in detecting a change in em field strength.
All i'm saying is, that as some part of nerve sytem has reasonable conductivity(otherwise no info can be transmitted by electrical means), there might be circumstances where a change in em field causes a slight current, which could then, if its strong enough, cause a sensation inside brain and then brain could conclude, if it can dismiss all other possible reasons, that a change in em field is the reason.
This is not to say that devices can't detect the electromagnetic radiation, but we can't.
Nearly all technical devices that detect electromagnetic radiation, are based on the fact, that em field changes induce currents. This could also happen inside a human body, though it might be so small, that other detection methods start to work far sooner, e.g. watch being torn off your arm, exploding technical devices, ...
Firstly, this effect would be down to gravity which increaes in strength as you get closer to the object - you can't be 'insulated' or shielded from gravity so this is a different effect and not analogous. (I can only see the effect you are talknig about occurring in relation to the position of the moon in the sky - overhead as opposed to at an angle).
Secondly it wouldn't be simply because the moon is full (all that means is that there is no earth shadow falling on the moon - that would not affect our weight).
Sorry, i made a stupid mistake there, of course it does not depend on moon being full, it depends on which side of earth the moon is compared to your position, i wrongly connected that to moon being full.
If the moon is from your point of view on the other side as earths center, then part or all(depending on exact positions) of the gravitational force caused by him is added to that caused by earth, you weigh a bit more, if the moon is on the same side of earths center, then its force is partly or fully substracted, you weigh less.
A more complete and correct explanation can be found on
http://www.badastronomy.com/bad/misc/tides.html
and
http://www.badastronomy.com/bad/misc/planets.html
though its hidden between debunking pseudoscientific mistakes.
This is like confusing the effect the moon has on the tides as being relevant to humans simply because we are 90% water. Gravity effects everything, water or not.
I was pointing at the gravitational effect of the moon to give an impression as to how well i personally guess a human could detect nearby normal technical used electric currents, sorry for misusing the word "level".
So I think that because our nervous system is electrical based you are assuming, incorrectly, that that gives us some ability to detect electricity, whilst being totally insulated from it. That would be like detecting visible light while behind a wall.
As i said, i personally think that a human is as good in detecting electricity, as he is capable to detect position of the moon via weight change of a magnitude around 0,6 gramm, so i do not believe anyone claiming he can do so, but i do not know enough about nervous system to be certain that under all circumstances with all known electrical devices its impossible.
Also I am confused as to what you mean by frequency of electricity? It's not like frequency of electromagnetic radiation in that the right frequency will beam electricity over a wide area.
I meant frequency of electric current, which is the same frequency the em field will have, that is caused by the current.
And the frequency is important, because all devices detecting em fields via induced current have frequency ranges where the induced current is big enough to be detected, outside these frequencies the detection will be bad or nil. If you tune your radio, you do nothing else than, via changing the current inside your radios antenna, change the frequency, where the detection is best, that way you avoid hearing all stations at once.
The same way there could be some frequencies, where the human nervous sytem is best at being affected by, though best might still not be good enough to notice anything and it might even depend on what person is doing, has eaten or drunk, is thinking and so on.
I think you're wrong about this, but I'd be interested if anyone knows differently.
Again, i just stated, that em field could change the current flow inside nervous system, but there are many buts and the biggest but is that change of everyday electrical devices is too small to be detected concious or unconciously.
But that might be different, if you use the output of a dozen electric power plants to create a single big em field with right frequency and put a human near the source of it.
Carn