* Most materials fall into two groups: conductors and insulators.
* A conductor allows electrons to flow through it.
* An insulator is a barrier to electricity.
* An insulator may act as a store of electricity known as static electricity.
* There is a small third group called semi conductors - these are used in electronics.

* The current is carried by ELECTRONS.
* Metals contain a "sea" of free electrons (negatively charged) which flow through the metal.
* This is what allows electric current to flow so well in all metals.
* Electric current will only flow if there are charges which can move freely (electrons).

* There are some things that you need to know for the exam about the difference between CONVENTIONAL and ELECTRICAL current.
* CONVENTIONAL current flows from POSITIVE TO NEGATIVE.
* ELECTRICAL current flows from NEGATIVE TO POSITIVE.
* So electrons flow opposite to the flow of conventional current.