What is the difference between Static Light Scattering (SLS) and Dynamic Light Scattering (DLS)?

Static light scattering measures the average scattered intensity of a population of particles in solution by integrating the scattered signal over a period of time. This output is then used to determine particle size and if the system is appropriately calibrated, molecular weight of the particles.

Dynamic light scattering monitors the fluctuations of the scattered photons over very short time intervals from the sample. This output is a direct indication of the Brownian movement of the particles and their diffusion characteristics which can then be used to determine particle size.