Difference From Rayleigh Scattering
Rayleigh scattering is defined by a mathematical formula that requires the light-scattering particles to be far smaller than the wavelength of the light. For a dispersion of particles to qualify for the Rayleigh formula, the particle sizes need to be below roughly 40 nanometres; and the particles may be individual molecules. Colloidal particles are bigger, and are in the rough vicinity of the size of a wavelength of light. It follows from scattering theory that Tyndall scattering (by colloidal particles) is much more intense than Rayleigh scattering. The importance of the size factor for intensity can be seen in the large exponent it has in the mathematical statement of the intensity of Rayleigh scattering. There is no equivalent mathematical statement for Tyndall scattering. But, if the colloid particles are spheroid, Tyndall scattering is mathematically analysable in terms of Mie theory, which admits particle sizes in the rough vicinity of the wavelength of light.
Read more about this topic: Tyndall Effect
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