The soil texture analysis (particle size distribution) yields the mass fractions of sand, silt and clay particles and allows to classify the texture of a soil. The sedimentation velocity of a given particle in a suspension depends on its size, shape, and mass. We use the differing sedimentation velocities to stepwise eliminate the particles larger than a given diameter d _{i} . At a given sampling time a spherical particle of this size would have traveled from the surface of the suspension to the depth of if the pipette . All particles larger than d i moved therefore out of reach of the pipette tip and can no longer be sampled. A sample taken with the pipette at given depth z i and time t_{ j }contains the mass fraction with particles d < d_{ i j} . Hence we determine the cumulative mass fraction containing particles not larger than d _{i j} .

Illustration on the measurement of the particle size distribution