How does electrical ground work? Why does electricity want to travel to the earth, which doesn’t seem particularly conductive?

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Some additional questions I have to further understanding:

Ships don’t have ground, but why couldn’t electricity on a ship ground to the ocean the same way houses ground to the earth?

A structure will have a grounding rod dug into the earth. Does the dirt, soil, and rock composition that the structure is built on affect how willing current is to use the path?

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Electrons repel one another. If they bunch up, it’s like a tank of compressed air. Give them a way to flow out, they do (like opening the valve on the air tank). The difference between the pressure where they are bunched up and the pressure where they are going is called a potential (volts for electricity, gauge pressure in kPa or psi for air). Electrons just move from higher potential to lower like air does from high to low pressure — until it’s even on both sides (for example, the battery is drained or the air pressure inside a tank matches the air pressure outside it).

In most electrical circuits, you have a source of electrons and a place for them to go, often with a positive charge (which, when paired with the negative charge of the electron becomes neutral). However, another possibility is to simply let the electrons flow to a space where instead of pairing up with a positive charge, they can simply spread out so far apart that they barely repeal one another. That’s an electrical “ground”, and the “potential” is low — the electrons there have no pressure to move anywhere. It can literally be the ground where the electrons jump across salts, minerals, and moisture in the earth, but it could also be just a huge sheet of metal or system of pipes where the electrons have lots of space to spread out.

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