Data compiled from a variety of sources follow Benford's law, which gives a
monotonically decreasing distribution of the first digit (1 through 9). We
examine the frequency of the first digit of the coordinates of the traject
ories generated by some common dynamical systems. One-dimensional cellular
automata fulfill the expectation that the frequency of the first digit is u
niform. The molecular dynamics of fluids, on the other hand, provides traje
ctories that follow Benford's law. Finally, three chaotic systems are consi
dered: Lorenz, Henon, and Rossler. The Lorenz system generates trajectories
that follow Benford's law. The Henon system generates trajectories that re
semble neither the uniform distribution nor Benford's law. Finally, the Ros
sler system generates trajectories that follow the uniform distribution for
some parameters choices, and Benford's law for others. (C) 2000 American I
nstitute of Physics. [S1054-1500(00)01402-6].