To measure the **bulk density **, a sample of undisturbed soil is taken in the field. The sample cylinder has an exactly defined volume. In the laboratory, the soil is dried and weighted. The weight of the dry soil expressed per volume is the bulk density.

The **real density ** is the density of the soil solids themselves, not including the pores. In order to measure the volume of the solids, the dried soil is filled into a jar of a known volume. To determine the jar volume, we weigh it filled with water at ambient temperature. The difference of the jar weights containing pure water and the soil suspension allows us to calculate the volume of the solids and then the real density of the sampled soil.