Three equivalent ways to say how densely the grains are packed. The solid fraction ν is the volume
of solids over the total volume. The porosity n = 1 − ν is the volume of voids over
the total volume. The void ratio e = n/(1 − n) = 1/ν − 1 is
the volume of voids over the volume of solids. The rulers are lined up so that one vertical line reads
all three for the same packing.
What you are seeing
- The rulers. Solid fraction from 0 to 1, left to right; porosity the same scale
reversed; and the void ratio at the same tick positions, so its spacing is not even and it grows
without limit towards ν = 0.
- The cursor. Move the mouse, or drag a finger, across the rulers: the vertical line
and the numbers beside it give ν, n and e at that point.
- The arrow. Loose packings lie to the left, dense ones to the right.