Colloid is the mixture in which one substance of microscopically dispersed insoluble or soluble particles is suspended throughout another substance. Because of Tyndall effect some colloids are translucent, which is the scattering of light by particles in the colloid. The cytoplasm of living cells is an example of a colloid, containing many types of biomolecular condensate. It covers interface science, including surface chemistry, physical chemistry, and surface tension.