Does anyone know why petrol and oil do not conduct electricity? I've never really thought about it, but the other day it dawned on me that they don't! Hence why you can use oil as a coolant in transformers.

I tried to work out why they don't, but on the face of it, I can't! It isn't the carbon in them because you have carbon film resistors. It's not the hydrogen in them because water conducts, and that contains hydrogen.

So can anyone shed some light on this one? It would be interesting to find out why

 

Water has impurities in the form of ions that conduct electricity (they actually move around). Interestinly enough distilled water doesn't conduct electricity. It will conduct a little as the water is broken down into hydrogen and oxygen (creating ions) but it'll read as a open circuit with a multimeter.

So oil, pure water, and gasoline don't have free valence electrons like metals do. So unless they have impurities they don't conduct.

I think that because all the free electrons in hydrocarbons are used up in molecular bonds there arn't any free elecctrons to move around. Same idea with silicon- if its pure and crytaline all the electrons are used up in molecular bonds and its non-conductive. but if you add impurities like boron and arsnic (I think these are the two common ones but you should be able to look this up) that add or remove electrons in the lattice it becomes conductive.

Brent

 

Phosphorus is another popular one.