question_answer 13)

               People use a variety of methods to wash clothes. Usually after adding tine soap, they beat the clothes on a stone or-beat them with a paddle, scrub with a brush or the mixture is agitated in  a washing machine. Why is this agitation necessary to get clean clothes?           

Answer:

The purpose of soap or detergent in washing is to reduce friction between oil drops carrying dirt particles and water so that they may mix with each other. All the methods that have been suggested loosen the bonds between the dust or oil particles and fabrics of clothes. The agitation helps in washing the clothes.