Electric conductivity

Electric conductivity

Electric conductivity


“What are the properties of materials that conducts electric current and how can we measure it?”

When pondering electrical insulators, many may wonder if there are any anti-thesis to such materials? Specifically, what are some properties of objects that conduct electricity? And how do they do so? First off all, we must think about how electric current works in the first place. Electric current is caused when a voltage potential difference interacts with the free-moving electrons within a lattice. These particles, being weakly bonded to their structure, are carried away in the direction of the potential difference. So logically, all current conducting materials (which will henceforth be referred to as conductors) must have an internal lattice with electromagnetic bonds that are not too powerful, and a path for electron travel.

With this knowledge, we can then delve further in to what geometric factors may affect the conductivity. If the cross-sectional area of the object is larger, then that means that the electrons have a greater area to travel through (remember, electrons do not move in a straight line, they bounce around the internal structure, so when the area gets wider, they have more room to move, which means less traffic and therefore less collision and therefore less resistance). Secondly, if the Length is longer, then there will be more internal resistance, which would lead to a slowdown.

After much research, scientists and engineers have come up with an analytic model of conductivity, with the equation G=(alpha)*A/L, with G being the capacitance, (alpha) being a constant, A being the cross sectional area, and L being the length. What’s even more interesting is that this relationship is directly inverse to the equation for  resistance! This is an amazing technical feat, because this means that human ingenuity was able to find a fundamental relationship between the resistance and conductivity of a material.

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