Elaboration on Benford's law and the distribution of first digits

Benford's law, which gives the probability distribution of first digits of a set of numbers, is examined from underlying distribution functions representing physical phenomena. Data satisfying the power law function y(x) infinity 1/x retain the same probability distribution of first digits when the data are subject to a scale change in the variable x. Exponential functions are shown to exhibit approximate invariance under scale change. Results are tested and examined using the data from the areas of 4013 lakes and 415 beta-decay half-lives.