For the example of the stiff/light part discussed above would have Young's modulus on one axis and density on the other axis, with one data point on the graph for each candidate material. On such a plot, it is easy to find not only the material with the highest stiffness, or that with the lowest density, but that with the best ratio E / ρ {\displaystyle E/\rho } . Using a log scale on both axes facilitates selection of the material with the best plate stiffness E 3 / ρ {\displaystyle {\sqrt[{3}]{E}}/\rho } .