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Science is an inherent contradiction — systematic wonder — applied to the natural world. In its mundane form, the methodical instinct prevails and the result, an orderly procession of papers, advances the perimeter of knowledge, step by laborious step. Great scientific minds partake of that daily discipline and can also suspend it, yielding to the sheer love of allowing the mental engine to spin free. And then Einstein imagines himself riding a light beam, Kekule formulates the structure of benzene in a dream, and Fleming’s eye travels past the annoying mold on his glassware to the clear ring surrounding it — a lucid halo in a dish otherwise opaque with bacteria — and penicillin is born. Who knows how many scientific revolutions have been missed because their potential inaugurators disregarded the whimsical, the incidental, the inconvenient inside the laboratory?”

Because of this, and despite the fact that it is common practice, it is sort of a mistake to find the resistance of a circuit element by plotting V vs I and finding the slope. Obviously, if the circuit element is non-ohmic it doesn’t make any sense to report a single R value. However, even if the circuit element can be nicely approximated by Ohm’s Law, it actually makes more sense to report the value of R as an average of all V/I ratios than it does to calculate the resistance by determining the slope of the best fit line.  This is especially the case if your best fit-line has a non-zero y-intercept.