Logarithmic scale

Definition

A logarithm answers how many tens multiply to reach a number, effectively counting zeros or decimal places. The pH scale is logarithmic, so each unit represents a tenfold concentration change.

Sørensen used a logarithm to compress concentrations buried under six or seven decimal places into a usable scale. The convenience is that one number captures an enormous range, but the danger is that small steps on the scale hide order-of-magnitude chemical shifts. Misreading the logarithm as linear is what caused the over-neutralization by a factor of a million in the chapter.

Related concepts

pH · pH definition formula · Orders of magnitude in pH

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Part of The Blueprint of Water · 📏 measurement