A good conductor allows the electric current to pass through it freely while an insulator does not allow the electric current to pass through it. Conductors are mostly metals like copper. Insulators are mostly non-metallic solids which have extremely high resistance towards the flow of charge and do not allow the charge to flow through them.
In a conductor, the outer electrons of the atoms are loosely bound and move freely through them. In an insulator, the atoms hold on to their outer electrons very tightly and they do not move freely through them.
An electrical conductor is an electric charge carrier (electrons) that move easily from atom to atom with the application of voltage. Conductivity is the ability to transmit electricity or heat. Good conductors are copper, gold, steel, aluminium, brass etc.
The flow of electrons in a conductor is known as the electric current. The force that is required to make that current flow through the conductor is known as voltage.
Eg. Copper is a good conductor of heat. This would explain why while heating one end of copper results in quick temperature rise on the other end. This happens because of the rapid flow of electrons. The conductivity of electricity of a conductor depends on the ease of flow of electrons through it. Protons don’t move as they are bound in atomic nuclei.
Conductivity depends on-
- Shape- the more thicker, the better the conductor
- Size – shorter the size, the better the conductor
- Temperature- with increase in temperature, electrons gain energy.
An insulator protects us from the hazardous effects of the electricity that flows through the conductor. The voltage in an electrical circuit can be extremely high with danger lurking around it, but an insulator helps to minimize the danger by not letting the electrical charge to flow through it. Examples of a good insulator include glass, rubber, plastic, wood and air.
Gold and lead make up for poor insulators as they are metals. Diamonds and concrete are non-metallic in nature with diamond being a better insulator, owing to its strong resistivity.
Organic molecules are primarily insulators in part as they are held together by the covalent i.e. the shared electron bonds and also because of the hydrogen bonding that helps in stabilizing the molecules.
Impurities can turn an insulator into a conductor. E.g. Pure water is an insulator, dirty water conducts weakly but salt water with its ions free floating, conducts well.