Microscopy: Microscopy techniques, such as optical microscopy, electron microscopy, and atomic force microscopy, can provide direct visualization and measurement of particles. This method allows for the measurement of individual particle sizes and shapes. Sieving: Sieving involves passing the particles through a series of sieves with progressively smaller mesh sizes. The retained particles on each sieve are weighed, and the particle size distribution is determined based on the weight percentages in each sieve. Sedimentation: Sedimentation techniques determine particle size based on the rate at which particles settle in a liquid medium. The most widely used method is the gravitational sedimentation method, where the settling velocity is measured and related to particle size using Stokes' law. Other sedimentation techniques include centrifugal sedimentation and photon correlation spectroscopy. Laser Diffraction: Laser diffraction is a widely used method for particle size analysis. It involves passing a laser beam through a dispersed particle sample and measuring the intensity and angle of the scattered light. Particle size distribution is then calculated based on the diffraction pattern. Dynamic Light Scattering (DLS): DLS, also known as photon correlation spectroscopy, measures the fluctuations in scattered light caused by Brownian motion of particles in a suspension. The analysis of these fluctuations provides information about the size distribution of the particles. Coulter Counter: The Coulter counter method determines particle size by measuring changes in electrical resistance as particles pass through a small orifice. Each particle disrupts the electrical current, and the magnitude of the disruption is related to the particle size. Nanoparticle Tracking Analysis (NTA): NTA is a technique used for sizing and tracking individual nanoparticles in solution. It utilizes a laser beam to illuminate particles, and a camera records their Brownian motion. Particle size is determined by analyzing the recorded particle trajectories. Dynamic Image Analysis: Dynamic image analysis involves capturing images of particles in motion and analyzing them to determine size and shape parameters. This method is particularly useful for irregularly shaped particles.