  Detailed investigation of static light scattering $(SLS) $ has been attempted
in this work using dilute water dispersions of homogenous spherical particles,
poly($N$-isopropylacrylamide) microgels and simulated data. When
Rayleigh-Gan-Debye approximation is valid, for large particles, the simple size
information, the static radius $R_{s}$ and distribution $G(R_{s}) $, can be
accurately obtained from SLS. For small particles, the root mean-square radius
of gyration $< R_{g}^{2}>_{Zimm}^{1/2}$ and the molar mass of particles
measured using the Zimm plot are discussed. The results show that the molar
mass measured using the Zimm plot over the average molar mass of particles is a
function of the size distribution. With the assistance of simulated data, the
effects of the reflected light and noises have been investigated in detail.
Measuring the static radius from the SLS data provides one method to avoid the
stringent requirements for the sample quantity and the instrument capability at
small scattering angles.
