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I have combed through various sources on the internet and I don't have a definitive answer for the above question:

The best that I can come think is the following:

Because when I remove synthetic clothes, the body gets charged one way, the clothes the other way. Then as I continue the process of removing the piece of clothing off my body, the charge build up is significant, owing to which the potential difference between the cloth and my body is greater than the breakdown potential of the air. Thus, electrons flow between my body and the piece of clothing I am removing. The air heats up, gets ionized, energy is dissipated in the form of heat, light and sound; in other words, as sparks.

Also one more follow up question: Do the sparks flow "inwards" between my body and the piece of clothing? Or just dissipate "outwards" into the air, towards nothing in particular?

Is the above reasoning sound?

Also, does the same reason hold when I comb my hair? However, if this were true, why do I NOT SEE any sparks when I comb my hair but only hear a crackling sound?

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    $\begingroup$ Have you tried combing your hair in the dark? $\endgroup$
    – g s
    Nov 29, 2023 at 0:02
  • $\begingroup$ @g s, okay resolved. But what about the other questions? Does my explanation make sense? $\endgroup$
    – S_M
    Nov 29, 2023 at 3:09

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The description in your main paragraph is correct. The phenomenon is the triboelectric effect. Dry skin (and dry hair) has an affinity for positive charge, while synthetic fabrics (and plastic) have an affinity for negative charge. When they rub against each other, especially when very dry, electrons flow from the skin or hair to the fabric or plastic comb.

The sparks go between the fabric and your body and between different parts of the fabric. Because the fabric is an insulator, it may have significant potential differences between various parts of the fabric, which discharge as the fabric changes shape. If you had a slow motion camera, the sparks would look just like miniature lightning bolts. The brightly glowing part starts at the region of greatest negative charge.

Likewise the sparks go between your hair and the comb, and there may possibly also be sparks between different parts of your hair as your unequally charged hair changes shape after a stroke of the comb.

If static electricity when combing your hair is undesirable, replacing your plastic combs with aluminum ones should solve the problem.

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    $\begingroup$ What's strange to me is that air breakdown field strength is about $3~\text{kV/mm}$. Does triboelectric effect generates so much charges just with a simple few strokes, to break the air for say $1 cm$ air path along ? Maybe discharge goes on if distance between body and cloth is $\lt 1 mm$ or even when they touches directly having points of contact ? I miss this explanation part of OP's question on air breakdown specific conditions of your otherwise great answer. $\endgroup$ Nov 29, 2023 at 7:43

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