There are different types of elements in our surroundings. These elements are organised into different categories based on their physical features like shape, size, colour, texture, polarity, malleability and solubility and so on.
One such important category based on which elements are classified is conductivity. That is, the ability of an element to allow ions or electrons freely. Based on their conductivity, elements are classified into conductors and insulators.
Conductor vs Insulator
The main difference between Conductor and Insulator is that the latter is resistant to the free flow of thermal or electric energy. The former on the other hand, is receptive to the flow of heat or electricity.
A conductor is described as a material that permits electrons to flow freely and easily from one particular to another in one or more than one directions. Such free flow of electrons allows the energy in the form of heat or electric charge to pass through the concerned material easily.
An Insulator, on the other hand, is a material that does not permit electrons to flow freely. On the contrary, it holds the electrons tightly within the atoms of a material and consequently obstructs the free flow of energy in the form of heat or electric current to pass through the material.
Comparison Table Between Conductor and Insulator (in Tabular Form)
| Parameter of Comparison | Conductor | Insulator |
|---|---|---|
| Definition | It refers to the elements that allow electric current or heat to pass through them. | It refers to the elements that do not permit electric current or heat to travel through them. |
| Electrons | It has free-flowing electrons. | It has tightly knit electrons. |
| Electric field | It is found on the surface of the material. | It does not exist in the material. |
| Conductivity | High | Low |
| Used for | Making electric wires, switches and sockets. | Making outer cover of the wires, switches and sockets. |
What is Conductor?
It refers to any of various substances that allow the movement of electric current or thermal energy. They have high conductivity and poor resistance to the flow of electric or thermal energy. This happens because of the presence of ‘free electrons’ in the atomic structure of a conductor.
‘Free electrons’ refer to those electrons which can be exchanged with the electrons of other atoms very easily. That is their bond with the atom of which they are a part lacks strength. This lack of strength permits the free flow of energy from one atom to another.
The extent to which a material or a substance allows charges or heat to travel through it depends on the number of ‘free electrons’ it possesses in the outermost orbits of its atoms. A substance or material can be said to be a good conductor if it has more number of ‘free electrons’ in the outermost or peripheral shells of its atoms.
Also, there should be no space between the conduction band and the valence band (known as the forbidden energy gap) so that the electrons can easily move to other atoms.
An object that is made of a material which has conducting qualities will receive the charges passed on it from another object and allow those charges to get distributed all over its surface unless the repulsive forces that exist between the surplus electrons reduce to the maximum extent possible.
Exchange of charges between two objects becomes easy if both of them are made up of conducting materials. It is interesting to note that most conductors are made up of metals such as mercury, copper, aluminium and silver and so on. Among these silver is considered to be the best conductor but it is not used for making electric wires because its cost is very high.
What is Insulator?
It is described as a substance or material that retards or blocks the flow of electric current or heat. Insulators have low conductivity and high resistance to the flow of thermal or electric energy. This happens because the atoms present in the insulators have a very strong covalent bond between them. Consequently, there is no free movement or exchange of electrons.
Also, insulators have a very large space known as the forbidden gap between the conduction band and the valence band which demands a lot of energy from the valence electrons to pass through this gap and reach the conduction band.
When some amount of charge or heat is passed on to an object made up of an insulating material, it continues to remain at the starting position and does not get dispersed across the outer layer of the object. Consequently, one needs to rub that object with a suitable material so that it gets charged. Another method that can be used to charge such an object is through induction.
In an electric circuit, insulators are mainly employed to keep the conductors apart from each other and from the other objects that exist around the circuit. Insulators ensure that current flowing through the wires remain within the wire and do not move away to any other object made up of a conducting material.
In the case of thermal energy, they break up the heat flow path by absorbing radiant heat. Most of the insulators are made up of non-metals like rubber, plastic, porcelain, mica, fibreglass etc.
Conclusion
It is important to note that the conductivity of a material depends on the structure of its atoms. A material may prove to be a good conductor if its atoms are unable to hold their outer electrons together. As it is because of these outer electrons, heat or electric charge can pass from one atom to another and therefore through the concerned material as a whole. If the atoms of a material have tightly knit electrons, the material proves to be a bad conductor or an insulator.
Nonetheless, both conductors and insulators are important for us especially when it is about handling electric appliances. Switches, sockets and electric plugs are made up of conductors. While, insulators like rubber and plastics are used for making the outer cover of switches, electric wires, sockets and other electrical appliances.
References
- https://link.springer.com/article/10.1134/1.1864209