7
$\begingroup$

I have been zapping people quite a lot recently (e.g. when shaking hands), probably due to new shoes. What I noticed is that usually I can't actually feel the shock, even though the other person quite clearly can.

Why are static electric shocks from person to person asymmetric? Should the current flow and resulting power dissipation not be felt by both?

$\endgroup$
1
  • 1
    $\begingroup$ I wonder if it has some sort of connection to the experiment where you hold a metal key so that the tip of the key takes the shock and you feel nothing. Could your fingers have some property that mimics this effect? I recall a grad student named Diane I went to school with years ago. She had an astonishing ability to discharge anything she touched. We actually compared previously charged objects after being touched by us and her, and when she touched them they were completely neutral afterwards, much more so than when others did so. It was very strange and interesting. $\endgroup$
    – user55515
    Apr 4 '16 at 10:13
1
$\begingroup$

Yes, the current is definitely the same :)

The power dissipation doesn't have to be equal - it's bigger for a bigger resistance. But I'm pretty sure you do not feel the power dissipation as heat, it is negligible. The effect is probably due to high voltage that tickles the nerves. So it should be proportional. It's therefore not conceptually correct to consider the power dissipated, but may lead to the right results. Though I think the maximal E-field is more important than the net voltage.

Try touching anothers arm with your finger, and also vice versa. This makes a big difference, I always noticed, the finger feels much less. This may of course be due to less sensitive skin on the fingertips (which is even more the case if you play the guitar or something like this).
But it is also because the more curved surface will have a lower potential to produce the same field in air, which is what counts for the discharge. So maybe the "lightning" is broader near the more curved surface, since the treshhold for ionization is easier reached there, whereas it concentrates on one point near the flat surface.
Edit: In the experiment with the key described in the comment you see, that a big cross section through which the current can flow makes you feel less.

I have not completely understood this, it is an interesting question. One should probably also make a test, if the direction of the current makes a difference...

$\endgroup$
1
  • $\begingroup$ +1 and thank you for your answer. I think you're pretty close here, but I'd like to see if someone else has more insight before accepting an answer. $\endgroup$ Apr 6 '16 at 22:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.