Edexcel IGCSE Physics 复习笔记 2.4.1 Conductors & Insulators

Conductors

• A conductor is a material that allows charge (usually electrons) to flow through it easily
• Examples of conductors are:
  • Silver
  • Copper
  • Aluminium
  • Steel

   

• Conductors tend to be metals

Different materials have different properties of conductivity

• On the atomic scale, 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

   

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

Insulators

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

   

• Overall, metals are very good conductors whilst non-metals tend to be good insulators

Conductors and Insulators Summary Table

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