Thanks for the explanation. I just drove somewhere and decided to put on a different pair of shoes (leather shoes although the sole was rubberized at some point because the leather got worn, we had a thin layer placed when the shoes were repaired). I tried hard as possible to "charge" myself in the seat, got out and couldn't get a spark to happen.
So assuming I am charging up myself in the seat, the charge needs to equalize. According to the triboelectric series table, leather tends to give up electrons and polyester attracts it. So I become negatively charged (or at least my jacket does). Now if I touch the car while I am still sitting in the chair, why do I not get shocked? How is that different than touching the car when I separate myself from the chair and step outside the car?
If I am negatively charged and the electrons want to jump back to the car (which is now positive or at least the seat is)... they won't go back if I touch the leather chair (e.g. if I get out of the car and touch the seat), but they will go back if I touch the metal frame of the car. I assume this is it is a less resistant path, or is it because the car has a huge reservoir of free electrons for which me touching it will make little difference to it overall? Same goes for when I get out and touch the ground. I must be discharging my electrons into the ground or whatever other large reservoir exists?
And if I am stepping out of the car with conductive soles (or barefoot) would I not feel a zap in my feet when I touch the ground? Or is it because I am still sitting? Somehow I am managing to separate myself from the chair but not yet equalized with anything (either ground or car) because the shoes are rubber, and then if I touch the car metal or pavement I will see a huge spark through my finger or a key. Somehow still being in the chair when I either touch ground or car causes the problem to go away... That is, touch car with my hand (either door or roof) or touch the ground with my conductive feet (or hands if I reach done). Either way, in each case I am still planted in the seat when I "equalize".
LET'S SEE... I THINK I FINALLY UNDERSTAND IT:
If you charge a capacitor and then you short out the leads, you see a large "zap" across it. So if my polyester jacket is one side of the "capacitor" and the leather seat is the other side, if I touch the metal of the car (even not getting up from the chair) WHY would this not discharge me just the same and result in a zap too? Why do I have to then separate my butt from the chair?
I imagine it like this: While I am in the chair, the electrons (even though they are in my jacket) are being attracted to the seat so they are pretty much "coating" my back. When I get away from the seat, the electrons spread out equality in my body as they are no longer attracted to the seat, they repel from each other and are trying to be as far away from each other as possible. If I touch the car, they are being repelled from each other and also I have excess number in my body, so they look for any opportunity to jump out of me into a much larger conductive free-electron source. If I touch another car, I assume the same would happen, just like touching the ground, or a large metal garbage bin, etc.
Somehow getting out of the car and touching the ground with somewhat conductive shoes also releases them but either my feet are not as sensitive or the sole "bleeds" it out slowly (like using a bleed resistor to discharge a capacitor). Because it is discharged more slowly I don't feel the shock.
Now if I am *still* in the seat, and I touch the metal frame of the car... I am also creating a path to the chair, yet it is not like shorting out a charged cap? Perhaps the path through the car back to the seat provides enough resistance (but not too much) to allow my electrons to flow back slowly, effectively discharging me "one side of the capacitor" to the leather chair. Now when I get out of the car, I am neutral so I no longer get zapped by the car. If my chair was on RUBBER supports in the car, would this still work? Now by touching the car it would not provide a path back to the chair... what would happen?
Seems like as long as my butt is planted in the chair, it is like the "capacitor" plates are close together, I can discharge the system slowly this way by providing a resistant path through from one plate to the other (by touching the car). The minute I separate the capacitor plates (my jacket and the seat) and then touch them to anything else, the spark develops. Getting out of the car in conductive shoes perhaps is the same as touching the car while I am still in the seat... it also lets charge flow back through to the car by going through the ground and back up through the tires and into the seat. Both instances, I am still in the seat... i.e. the plates are in close proximity still when the discharge happens.
Am I thinking this through properly?
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