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sfsolarboy OP t1_iqpzybr wrote

So far none of the replies have explained why two pieces of string when dangled next to each other will twist together before one's very eyes.

Just saying "entropy" feels like a philosophical answer but I was hoping to learn what is drawing the electrons toward each other. What is actually happening?

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_mick_s t1_iqqh4ux wrote

What others are talking about is more tendency for strings to tangle, but I think you're talking about something different.

I think what happens is that wire is already twisted internally so it wants to untwist, but since there's another wire next to it that's also untwisting they twist around each other instead.

It might help if you make a photos of what you're describing.

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breadandbits t1_irqh1yf wrote

I think this is correct. It would be dangerous for this to occur with climbing ropes, so they are made with equal spirals in opposite directions so that stretching does not impart twist. It can be referred to as being torque balanced. Stranded electrical wire is generally twisted in the same direction, so every time you and/or gravity pulls on it, it twists. You’ll notice that your headphones always twist in the same direction.

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