Colloids. Washing in water

At the end of this activity, students should be able to:
– explain what colloids are
– name the properties that distinguish colloids from other types of mixture (true solutions and suspensions)
– list the types of colloid and give examples of them
– explain what emulsifying agents are and what coagulation involves
– explain how soap and detergents remove dirt
– describe the behaviour of soap and detergents in hard water.