• Question: Why do insulators not conduct electricity well?

    Asked by smithmoorebell to Ben, Clare, Ezzy, Mario, Sam on 13 Mar 2012.
    • Photo: Mario Campanelli

      Mario Campanelli answered on 12 Mar 2012:


      their atomic structure does not have enough free electrons, and free electrons are what conducts electricity

    • Photo: Sam Vinko

      Sam Vinko answered on 12 Mar 2012:


      To conduct electricity you need to have a material containing mobile carriers of charge. This is so that when you apply a potential to the material, the charge can move in response, and generate an electric current. An insulator is a material which when you apply an everyday potential to it (for example, the 12V plug in a car, or the 1.5V of a standard AA battery), no current can flow.

      Note that this is a relative notation – if you apply an increasingly higher potential, everything eventually starts to conduct current (becomes a conductor) as everything is made of ions and electrons: if the potential is high enough, they electrons will be freed and will travel generating a current. Air, for example, is an insulator, but if you make a potential strong enough you’ll strip electrons off the atoms and create a plasma which will also make a spark – thats the air becoming a conductor! If you have a gas burner at home you can see how this works – the spark that starts the flame works on this principle. In a much more dramatic exhibition, so does lightning, which is just the path along which air becomes a conductor in a storm due to large potential unbalances caused by static electricity.

    • Photo: Elizabeth Pearson

      Elizabeth Pearson answered on 13 Mar 2012:


      Metals have atoms that arrange themselves in such away there’s a free elctron on doing much. That’s what carries the charge. Insulators don’t have that so can’t carry electricity that way. They can sometimes do it other ways, but they don;t happen as easily.

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