what is tyndall effect

The Tyndall effect is the scattering of light by particles in a colloid such as a very fine suspension/Physical_Properties_of_Matter/Solutions_and_Mixtures/Colloid/Tyndall_Effect). It is also known as Tyndall scattering and is similar to Rayleigh scattering, in that the intensity of the longer wavelengths is transmitted more, while the shorter wavelengths are more diffusely reflected via scattering. The Tyndall effect is seen when light-scattering particulate matter is dispersed in an otherwise light-transmitting medium, where the diameter of an individual particle is in the range of roughly 40 to 900 nm, i.e. somewhat below or near the wavelengths of visible light (400–750 nm) . The effect is particularly applicable to colloidal mixtures, and it is used in nephelometers to determine the size and density of particles in aerosols and other colloidal matter. The phenomenon led directly to the invention of the ultramicroscope and turbidimetry. The Tyndall effect is named after the 19th-century physicist John Tyndall, who first studied the phenomenon extensively.