OVERVIEW: Every thing in the world is differentiable on the basis of its electrical conductance. Some things are called insulators and these substances never conduct electricity. they include things such as cold air,wood and plastic. Then there are things that conduct electricity and current flows through them, they are called conductors. examples of conductors are most metals like copper and steel. Other materials that are sometimes used as conductors are silver, gold, and aluminum. Copper is still the most popular material used for wires because it is a very good conductor of electrical current and it is fairly inexpensive when compared to gold and silver. Aluminum and most other metals do not conduct electricity quite as good as copper.
The electrons of different types of atoms have different degrees of freedom to move around. With some types of materials, such as metals, the outermost electrons in the atoms are so loosely bound that they chaotically move in the space between the atoms of that material by nothing more than the influence of room-temperature heat energy. Because these virtually unbound electrons are free to leave their respective atoms and float around in the space between adjacent atoms, they are often called free electrons. Also, this relative mobility of electrons within a material is known as electric conductivity. Conductivity is determined by the types of atoms in a material (the number of protons in each atom's nucleus, determining its chemical identity) and how the atoms are linked together with one another. Materials with high electron mobility (many free electrons) are called conductors, while materials with low electron mobility (few or no free electrons) are called insulators.
Some substances that conduct at high temperatures are called semi conductors. they do not conduct as good as conductors but have various uses that make them more versatile than conductors themselves. Lastly, are