Disadvantages Of Electrical Conductivity

Electrical conductivity is a measure of how well a material allows the movement of electrically charge (Nave, n.d.). In a circuit, electrical charge is transferred by the movement of negatively charged electrons and flows from the negative terminal of a battery or power supply – where there is a surplus of electrons – to the positive terminal – where there are less electrons (Kuphaldt, n.d.). Electrical circuits can be found in everyday life, for example in house lighting, in which wires conduct electricity to the light bulb where it is converted to light energy. The conductivity of a material is dictated by its atomic bonding. Metals have high conductivity as their valence electrons are loosely bound to the nucleus of the atom, meaning that they are able to move freely and hence transfer electrical charge through the material (Georgia State University, n.d.). In contrast, non-metals are usually insulators as the electrons are tightly bound to the nucleus of the atom, inhibiting the transfer of electrical charge through the material due to the lack of free electrons (Fitzpatrick, 2007). These non-conductive …show more content…
This is because of graphite’s chemical make-up. Graphite is one of the crystalline allotropes (physical forms) of carbon – the other being diamond – and is made up of planes of carbon atoms (refer to Figure 1). Within these planes each carbon atom is covalently bonded to three other carbon atoms (Bodner Group, n.d). Therefore, while three of the valence electrons of each carbon atom are tightly bonded, the fourth valence electron is not and is therefore able to move freely (refer to Figure 2), allowing the flow of electrical current (St Aidan 's Anglican Girls ' School, 2013). Hence, as the percentage of graphite in the pencil increases (e.g. the pencil is changed from 2B to 4B), the resistance decreases due to the higher conductivity of the pencil (refer to figure