In the last blog, we read about electrons.Let us study the movement of electrons.

The electrons of different types of atoms have different degree of freedom to move around. There are some materials in which electrons can move freely from one atom to another. Their movement constitutes current and electricity can pass through them. Such materials are called conductors.
Examples of conductors are silver, aluminium, steel, copper, gold, iron, brass, bronze, mercury, graphite, dirty water and human body.

Basically, all metals are conductors of electricity.

Materials in which electrons cannot move freely from atom to atom are insulators. Electric current cannot flow through them. Some examples of insulators are glass, rubber, oil, fiber glass, porcelain, ceramic, quartz, cotton, paper, plastic, air, wood, diamond and pure water.

Both conductors as well as insulators are important for us and are needed.

Electric wires / current carrying wires are made of aluminium or copper so that electricity can be transferred from the socket to the gadget (e.g., computer, microwave, etc.) but the outer coating is of plastic. Plastic is an insulator which protects us from electric shocks because human body is a good conductor. When current passes through our body, it is dangerous and causes injury.