Electrical Conductors & Insulators (Cambridge (CIE) IGCSE Co-ordinated Sciences (Double Award)): Revision Note

Electrical conductors & insulators

Conductors

• A conductor is a material that allows charge (usually electrons) to flow through it easily

• Some examples of conductors are:

  • silver

  • copper

  • aluminium

  • steel

• The best conductors tend to be metals

• On the atomic scale, metallic conductors are made up of positively charged metal ions with their outermost electrons delocalised

  • This means the electrons are free to move

• Metals conduct electricity very well because:

  • Current is the rate of flow of electrons

  • So, the more easily electrons are able to flow, the better the conductor

Metallic lattice structure

The lattice structure of a conductor with positive metal ions and delocalised electrons

Insulators

• An insulator is a material that has no free charges and, hence does not allow the flow of charge through it very easily

• Some examples of insulators are:

  • rubber

  • plastic

  • glass

  • wood

• Some non-metals, such as wood, allow some charge to pass through them

• Although they are not very good at conducting, they do conduct a little in the form of static electricity

  • For example, two insulators can build up charge on their surfaces and if they touch this would allow that charge to be conducted away

Conductors and insulators

Different materials have different properties of conductivity