Exploring the effect of increasing energy on a particulate system is the general approach to method development in laser diffraction. In this manner agglomerates can be distinguished from primary particles. Energy is applied by altering the differential pressure (P) in a dry measurement in the pressure-size titration approach and in the wet systems by application of ultrasound energy in the before, during, and after sonication (BDAS) approach. This seminar will illustrate the methodologies by means of appropriate examples and reference to ISO 13320: 2009