This turbidity can be measured by an instrument called a nephelometer. Beginning in the 1970s, Clive Coogan, from the Division of Chemical Physics, developed a new instrument, known as the Fibre Optic Nephelometer that was a significant advance in the measurement of turbidity.
What is the principle behind the working of nephelometer?
The principle of nephelometry and turbidimetry is based on the scattering or absorption of light by solid or colloidal particles suspended in solution. When light is passed through the suspension, part of incident radiant energy is dissipated by absorption, reflection, and reaction while remainder is transmitted.