Colloid and surface chemistry is a core subject of physical chemistry. Colloids are characterized by their many interesting properties e.g. kinetic or optical as well as by observing their stability over time. Colloidal systems are composed of small particles dispersed in a medium.  The fact that these particles have such small dimensions is the reason that a huge surface or interfacial area is created.  The huge interface associated with colloids is the reason why colloid and surface chemistry are often studied together. 

Colloids and interfaces are present and important in many products and processes, included;