The presence of salts influences most physical properties of sea water (density, compressibility, freezing point, temperature of the density maximum) to some degree but does not determine them. Some properties (viscosity, light absorbtion,refractive index) are not significantly affected by salinity. (Particle and dissolved matter do affect light absorption in sea water and this influence is used in most optical applications.) Two properties which are determined by the amount of salt in the sea are conductivity and osmotic pressure.