| Conductors | Insulators |
|---|---|
| Substances which have large number of free electrons are called conductors. | Substances which have very less number of free electrons or no free electrons are called insulators. |
| They allow the electricity to flow through them. | They do not allow the electricity to flow through them. |
| They cannot be charged by rubbing. | They can be charged by rubbing. |
| Metals like silver, copper, aluminium etc. are conductors. | Substances like wood, paper, glass, rubber etc. are insulators. |