Why is it shocking?

Question

Physics

If you stand on a concrete field and touch a bare wire, it will give you an electric shock.
If, in the same way, they touch it with a piece of concrete, holding it in their hands, it will not shock.
Why is that? Those. changed parts of the circuit in places (man and concrete) and the current no longer passes through them.
And in general, why does it shock in the first case if concrete does not conduct electricity? We are talking about dry concrete. The current will not be able to flow through a person into concrete and further into the "ground" (where it will close with zero, i.e. the second wire of the socket).

Answer 1

AC current? Then the system "human body" - "earth" is a capacitor that passes alternating current. The capacitance of such a capacitor is units or tens of picofarads.
If you take the wire directly, then a small alternating current charges / discharges the resulting capacitor. If there is no direct contact with the conductor, then the current does not pass through this capacitor.

Answer 2

Current follows the path of least resistance.
Therefore, changing places does not save you.

Answer 3

A little late, but I will give my version of the answer.
The bottom line is that concrete has some resistance due to the moisture and impurities it contains (maybe in theory it is a dielectric, but in practice it is not so). The concrete floor has a large volume (here we draw an analogy with parallel-connected resistances - the resulting resistance drops when connected in parallel, and the current increases) and a large area of ​​\u200b\u200bcontact with the ground, respectively, its (concrete floor) resistance is low enough to create the current strength that you able to feel, with alternating current it is 0.6-1.5 mA.
If you pick up a piece of concrete, then its volume is very small, the contact area with the conductor is negligible, the resistance is large and it cannot create a noticeable current for a person.
PS The main thing in such experiments is not to achieve a floor resistance capable of creating a current above 10-15mA (alternating current) - this is a non-releasing current, in which, due to muscle spasm, a person is not able to free himself from contact with the conductor.

Answer 4

Because when you touch the wire with your hand, wet fingers conduct current well, and then through wet heels and a large contact area, the current also goes well into the ground. When you touch a wire with concrete, the contact area is negligible and therefore high resistance.
And the downvoted Rsa97 is wrong in the general case, because the capacitor does not care if it is charged through concrete or directly through the skin; and right in private, when we can stand in rubber boots and the conductivity of the surface on which we stand does not matter. But it seems to me that in the second case the currents will be so small that we won't even feel anything. I have never specifically taken on the bare phase, I could be wrong.