Tell me more ×
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It's 100% free, no registration required.
up vote -1 down vote favorite

Why is that when you scuff with your shoes on, charges move (since electrometer moves back and forth), but if you dont have your shoes on, the electrometer doesnt move

Here is the corresponding video detailing the event.

It is at about 47 min of video from beginning. I don't get the logic behind it

share|improve this question
Some things like to hang on to electrons more than other things. Maybe without your shoes, your feet and the carpet are about equal in their affinity for electrons. google "triboelectric series" and compare the materials in your socks with the materials in your carpet. – JustJeff Apr 13 '12 at 4:24
This is a pure physics question which would be best at physics.stackexchange.com – Kellenjb Apr 13 '12 at 12:15

closed as off topic by Kellenjb, Madmanguruman, embedded.kyle, The Photon, Kaz Nov 26 '12 at 3:07

Questions on Electrical Engineering Stack Exchange are expected to relate to electronics design within the scope defined in the FAQ. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about closed questions here.

2 Answers

up vote 1 down vote accepted

The video explains it rather well, actually.

Let's assume that socks and shoes move the same amount of charge. It is a tiny amount of charge, which gets stored in the capacitor formed by our body.

This stored charge gets discharged across the resistance from the body to the surroundings.

The lower the resistance, the faster the discharge. If the resistance is low enough, the charge wont even create a noticeable voltage change in the capacitor, because it is discharged faster than it is created.

So, if you are wearing shoes, the resistance is big enough to get a noticeable charge stored up.

Wearing socks, the resistance is lower (thinner layer not made of a very good insulator), and the charge dissipates as soon as it is generated.

The creation of static electricity is called the tribologic effect.

share|improve this answer
Tnx. Its nOw clear! – vvavepacket Apr 15 '12 at 12:42
up vote 2 down vote

The best arc I have generated was using neoprene soled shoes on nylon carpet in a hotel during a dry winter.

I know from experience you can generally calculate the high voltage as 1kV/mm gap or 1 million volts per meter gap. With a pointy antenna it takes less voltage than large round balls to breakdown due to the electric field fringe effects.

Anyways, it was a good 2 inch arch using the hotel key to the door handle or 50 mm = 50kV

But back in the 80's when I was Test Mgr at Burroughs, we implemented ESD controls in mfg. and had instruments to measure body charge voltage. After ground yourself and raising one leg, yu could generate a couple hundred volts easy. This is due to the distribution of charges in the body and changing your body position

Q=CV means changing the body capacitance changes the voltage for the same charge. So that explains why even when not causing a friction or tribilectric charge up you can create an electric field from slow motion. Xmas Tinsel on an old tube type TV set is the easiest way to see the effects of an electric field with your hand and the tinsel pointing directly towards the TV.

share|improve this answer
Tnx for ur info – vvavepacket Apr 15 '12 at 12:42

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