Now, the outside of electric wires are usually covered in plastic because it’s a very poor conductor. It hardly conducts any electricity at all, so we can say it’s an electrical insulator.

For electricity to flow, you need a conductor. That plastic bottle, that’s an insulator, they don’t let electricity pass through. No, not that either, wood’s an insulator too. We’ve got to ...

On the periodic table, semiconductors (also known as metalloids) crop up along a diagonal line between conductors and insulators. Noble gases such as helium and neon are poor conductors of ...